IPP Annual Report 2007 - Max-Planck-Institut für Plasmaphysik ...
IPP Annual Report 2007 - Max-Planck-Institut für Plasmaphysik ...
IPP Annual Report 2007 - Max-Planck-Institut für Plasmaphysik ...
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<strong>Annual</strong> <strong>Report</strong> <strong>2007</strong><br />
<strong>Max</strong>-<strong>Planck</strong>-<strong>Institut</strong><br />
<strong>für</strong> <strong>Plasmaphysik</strong><br />
EURATOM Association
Simulation of the plasma radiation load onto the plasma vessel of Wendelstein 7-X. The image shows a tangential 3D<br />
view into the plasma vessel across the triangular symmetry plane of the Wendelstein 7-X plasma. The white points represent<br />
the distribution of start points of the photon tracing calculations localized in toroidal direction and around the last<br />
closed magnetic surface. The finite surface elements of the plasma vessel model are colored according to the element<br />
averaged local heat flux.
<strong>Annual</strong> <strong>Report</strong> <strong>2007</strong><br />
The <strong>Max</strong>-<strong>Planck</strong>-<strong>Institut</strong> <strong>für</strong> <strong>Plasmaphysik</strong> is an<br />
institute of the <strong>Max</strong> <strong>Planck</strong> Gesellschaft, part of<br />
the European Fusion Programme (Euratom) and<br />
an associate member of the Helmholtz-<br />
Gemeinschaft Deutscher Forschungszentren.
The year <strong>2007</strong> saw substantial progress in the establishment of the ITER process.<br />
Following the ratification of the ITER Agreement by all the Parties the International<br />
Organisation came officially into being on 24 th October. The first meeting of the ITER<br />
Council took place on 27 th November. A design review by an international panel of fusion<br />
engineers and scientists (see below) resulted in a set of recommendations which are still<br />
under consideration by the ITER Organisation. The preparation of the site in Cadarache<br />
has started with particular care being taken to minimise the environmental impact. The<br />
EU Domestic Agency, “European Joint Undertaking for ITER and the Development of<br />
Fusion Energy”, known as “Fusion for Energy (F4E)”, with its seat in Barcelona, was<br />
established by the Council of the European Union at its meeting in Brussels on on 27 th<br />
March. Didier Gambier, formerly EU Commission, was subsequently appointed its first<br />
Director by the F4E Governing Board and took up his duties on 1 st October.<br />
For Wendelstein 7-X, the large superconducting stellarator under construction at the<br />
Greifswald site of the <strong>Max</strong>-<strong>Planck</strong> <strong>Institut</strong>e for Plasma Physics, the past year has been of<br />
particular importance. The assembly of the first magnet modules was re-started following<br />
a long interruption due to systematic defects in certain non-planar coils and after additional<br />
mechanical reinforcement of the support structure. The assembly plan was completely<br />
revised and a new, much more robust concept developed based on a step-wise<br />
approach towards steady-state operation with fusion-relevant plasmas. This plan results<br />
in the completion of the device in mid-2014 with a temporary divertor and first operation<br />
with short pulses at full power about a year after commissioning. This phase is intended<br />
to demonstrate the main physics aim of this fully optimised stellarator, namely, good<br />
confinement of the α-particles combined with the avoidance of intrinsic plasma currents<br />
which change the topology of the magnetic field. The final, water-cooled divertor for<br />
steady-state operation at full power will follow in a later completion phase. The assembly<br />
is now progressing well. The project team has been reinforced, particularly with engineers.<br />
In order to meet the daily requirements of the device construction, the project<br />
structure has been revised and a new organisational form implemented.<br />
At present, the main focus of the ASDEX Upgrade tokamak programme at the Garching<br />
site is to give physics input to critical elements of the ITER design and to prepare for<br />
ITER operation. In <strong>2007</strong> the main hardware enhancement to ASDEX Upgrade was the<br />
completion of the tungsten programme, allowing for the first time the behaviour of tungsten<br />
as a wall material in a divertor tokamak for ITER-relevant plasma scenarios to be<br />
studied. In order to substantiate the results for an all-tungsten wall, start-up and operation<br />
in <strong>2007</strong> were carried out without any boron coating applied. H-mode discharges<br />
with confinement and stability properties sufficient for the standard operating conditions<br />
envisaged for ITER were achieved. The operational space was found to be restricted by<br />
impurity accumulation for both low heating power at the centre and low density/gas puff<br />
levels. Another restriction is on the use of ICRH with tungsten-coated ICRH limiters,<br />
where impurity ions accelerated in the rectified sheath of the active antennae led to<br />
substantial sputtering and hence influx of tungsten. ECRH heating at the centre of the<br />
plasma continues to be very effective in preventing accumulation.<br />
The scientific goal of plasma theory at the <strong>Max</strong>-<strong>Planck</strong> <strong>Institut</strong>e for Plasma Physics is the<br />
ab initio understanding of all the relevant phenomena associated with magnetically confined<br />
plasmas. Conclusions and predictions can be verified on existing experiments and<br />
applied to the planning for Wendelstein 7-X, ITER and the projected demonstration<br />
reactor DEMO. A main thrust is the development of rigorous gyrofluid and gyrokinetic<br />
models for the direct simulation of plasma turbulence and of the resulting energy and<br />
particle transport. The analysis of large-scale magnetic perturbations has also recently<br />
become a focus of attention, not only due to the future possibility of active feedback-
control but also because of the novel physics arising from the interaction with fast fusionproduced<br />
α-particles. More empirically based, but motivated by an overwhelming practical<br />
need, are the contributions of the <strong>Institut</strong>e to edge and divertor-plasma modelling.<br />
JET was operational for the first three months of the year. The ITER-relevant experiments<br />
to elucidate the effect of the toroidal field ripple were a highlight. A noticeable difference<br />
in confinement, toroidal rotation, ELM frequency and amplitude between JET and JT-60U<br />
in Japan was found in otherwise identical discharges. In the following months JET operation<br />
was interrupted to install the ITER-like ICRH antenna as well as a new pellet injection<br />
system. Parallel to the shutdown, the JET EP2 project has proceeded well and the<br />
2008 campaigns C20-C25 were prepared. The MPI for Plasma Physics has been<br />
involved in many of these activities. In particular, two scientists from the <strong>Institut</strong>e were<br />
appointed to support the management of the JET Task Forces S1 and E.<br />
A major new part of the contribution of the <strong>Institut</strong>e to ITER during <strong>2007</strong> was participation<br />
in the design review. The design review panel was divided into working groups<br />
which were charged with evaluating and prioritising the list of open issues in the ITER<br />
design and with finding appropriate solutions. The MPI for Plasma Physics also contributes<br />
actively to the physics definition of ITER via the International Tokamak Physics<br />
Activity. The expertise of the <strong>Institut</strong>e is in demand for a wide range of activities in<br />
support of ITER, based not only on the results from ASDEX Upgrade but also on knowhow<br />
in the Technology, Theory, Materials and Stellarator Divisions. This work ranges<br />
from studies of plasma scenarios to work on specific heating and diagnostic systems.<br />
Within the project “Plasma-facing Materials and Components” the areas of plasma-wall<br />
interaction studies, material modification under plasma exposure, development of new<br />
plasma-facing materials and their characterisation have been merged to form a field of<br />
competence at the <strong>Institut</strong>e. The work supports the development of fusion devices at the<br />
<strong>Institut</strong>e and also generates basic expertise with regard to plasma-facing components in<br />
ITER and fusion reactors. The activities are strongly embedded in the materials research<br />
community: The MPI for Plasma Physics coordinates the large EU Integrated Project<br />
“ExtreMat” with 37 partners and heads the European Task Force on Plasma-Wall<br />
Interactions.<br />
Following a year of consolidation the Directorate and the Board of Scientific Directors<br />
are confident that the project Wendelstein 7-X is now back on track and that the new<br />
completion date will be kept. Fortunately, the ASDEX Upgrade Team has overcome the<br />
limitations caused by the severely damaged flywheel generator EZ4. The excellent work<br />
of the staff in all Divisions in <strong>2007</strong> has ensured that the <strong>Institut</strong>e will continue to play a<br />
central role in international fusion research.<br />
On behalf of the Directorate and the Board of Scientific Directors I would like to thank<br />
them all for their invaluable contributions.<br />
Scientific Director Alex Bradshaw
Tokamak Research<br />
ASDEX Upgrade . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3<br />
JET Cooperation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .25<br />
Stellarator Research<br />
Wendelstein 7-X . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .29<br />
Laboratory Plasma Devices WEGA and VINETA . . . . . . . . . . . . . .61<br />
ITER<br />
ITER Cooperation Project . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .65<br />
Plasma-wall-interactions and Materials<br />
Plasma-facing Materials and Components . . . . . . . . . . . . . . . . . .71<br />
Plasma Theory<br />
Theoretical Plasma Physics . . . . . . . . . . . . . . . . . . . . . . . . . . . . .81<br />
Supercomputing and other Research Fields<br />
Computer Center Garching . . . . . . . . . . . . . . . . . . . . . . . . . . . . .95<br />
Energy and System Studies . . . . . . . . . . . . . . . . . . . . . . . . . . . . .99<br />
Electron Spectroscopy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .101<br />
Content<br />
University Contributions to <strong>IPP</strong> Programme<br />
Cooperation with Universities . . . . . . . . . . . . . . . . . . . . . . . . . .105<br />
University of Augsburg<br />
Lehrstuhl <strong>für</strong> Experimentelle <strong>Plasmaphysik</strong> . . . . . . . . . . . . . . . .107<br />
University of Bayreuth<br />
Lehrstuhl <strong>für</strong> Experimentalphysik III . . . . . . . . . . . . . . . . . . . . . .109<br />
Humboldt-University of Berlin<br />
Arbeitsgruppe <strong>Plasmaphysik</strong> . . . . . . . . . . . . . . . . . . . . . . . . . . .111<br />
Technical University of Munich<br />
Lehrstuhl <strong>für</strong> Messsystem- und Sensortechnik . . . . . . . . . . . . .113<br />
University of Stuttgart<br />
<strong>Institut</strong> <strong>für</strong> Plasmaforschung (IPF) . . . . . . . . . . . . . . . . . . . . . .115<br />
Publications<br />
Publications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .119<br />
Lectures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .149<br />
Teams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .175<br />
Appendix<br />
How to reach <strong>IPP</strong> in Garching . . . . . . . . . . . . . . . . . . . . . . . . . .178<br />
How to reach Greifswald Branch <strong>Institut</strong>e of <strong>IPP</strong> . . . . . . . . . . . .179<br />
Organisational structure of<br />
<strong>Max</strong>-<strong>Planck</strong>-<strong>Institut</strong> <strong>für</strong> <strong>Plasmaphysik</strong> . . . . . . . . . . . . . . . . . . . .180
Tokamak Research
1 Overview<br />
1.1 Scientific Aims and Operation<br />
The tokamak fusion experiment<br />
ASDEX Upgrade (AUG) is a<br />
medium size divertor tokamak<br />
(major radius R=1.65 m, minor<br />
radius a=0.5 m) with an ITERlike<br />
configuration, high shaping<br />
capability (single null and double-null<br />
divertor, elongation up<br />
to 1.8, triangularity δ up to 0.5)<br />
and a versatile heating system. The design combines the successful<br />
divertor concept with the requirements of a fusion<br />
reactor, in particular the need for an elongated plasma shape<br />
and poloidal magnetic field coils outside the toroidal magnetic<br />
field coils. AUG is close to ITER in its magnetic and<br />
divertor geometry and in particular the relative length of<br />
both divertor legs compared to the plasma dimensions. The<br />
installed heating power of up to 28 MW ensures that the<br />
energy flux through the plasma boundary is equivalent to<br />
that in ITER. The scientific programme gives priority to the<br />
preparation of the design (heating, fuelling, first wall materials),<br />
physics basis and discharge scenarios of ITER and the<br />
exploration of regimes beyond the ITER baseline scenario.<br />
The <strong>2007</strong> programme was co-ordinated by four Task Forces<br />
(TF), which consisted of<br />
– Confinement and performance of the ITER base-line<br />
scenario, the ELMy H-mode, and the advanced scenario<br />
of the “improved H-mode” leading to enhanced performance<br />
and longer inductive pulse lengths by non-inductive<br />
current drive,<br />
– H-mode pedestal physics and ELM mitigation and control,<br />
– Magnetohydrodynamic (MHD) stability, active stabilization<br />
of β limiting instabilities as well as avoidance and<br />
mitigation of disruptions,<br />
– Scrape-off layer and divertor physics with the aim of optimizing<br />
power exhaust and particle control (ash removal)<br />
and optimization of first wall material with emphasis on<br />
tungsten.<br />
The similarity of ASDEX Upgrade to ITER makes it particularly<br />
suited to testing control strategies for shape, plasma<br />
performance and MHD modes. The similarity in cross-section<br />
to other divertor tokamaks as e.g. JET is important in determining<br />
size scalings for core and edge physics. Our programme<br />
largely covers the “High Priority Physics Research<br />
Areas” provided by the ITPA Co-ordinating Committee.<br />
Again, several items have been investigated in joint experiments<br />
at all major tokamaks as proposed by the ITPA<br />
Topical Groups. In summary, the AUG programme in close<br />
collaboration within the EU fusion programme is embedded<br />
in a framework of national (see section 8) and international<br />
collaborations (see section 9).<br />
ASDEX Upgrade<br />
Head: Dr. Otto Gruber<br />
The aim of the ASDEX Upgrade programme is<br />
to prepare the physics base of ITER and DEMO.<br />
The full performance H-mode operation with<br />
unboronized, fully tungsten coated walls achieved<br />
in <strong>2007</strong> is a significant step forward. Progress has<br />
been made in the understanding of ICRH produced<br />
impurities, tungsten wall behaviour and fast<br />
ion losses driven by MHD instabilities. Extensions<br />
of ECRF and installation of active in-vessel<br />
coils for ELM and MHD control are under way.<br />
3<br />
The AUG Programme Committee<br />
(PC) established in 2001<br />
enables the Associations to take<br />
responsibility for our near term<br />
programme. This PC defines the<br />
TFs responsible for the different<br />
elements of our programme, and<br />
approves the experimental programme.<br />
Furthermore, the bodies<br />
that work out the programme<br />
proposals are open to external<br />
participants, and remote participation<br />
in the meetings is used. With this structure, we have<br />
achieved a compromise between the international involvement<br />
and the flexibility that has so far been typical for the<br />
AUG programme. For the <strong>2007</strong> experimental campaign, 60 of<br />
the 178 proposals were from outside <strong>IPP</strong> from 14 EURATOM<br />
Associates, the US and Japan.<br />
The flexible heating systems of AUG consist first of the<br />
neutral beam heating (NBI) with power up to 20 MW. The ion<br />
cyclotron resonance system (ICRF) is capable of routinely<br />
coupling up to 6 MW in ELMing H-mode discharges, but is<br />
restricted with tungsten (W) wall by W sputtering caused by<br />
light impurities accelerated in the RF antenna sheath. The<br />
present electron cyclotron system ECRH-1 was kept available<br />
up to a coupled power of 1.6 MW, and the first new 1 MW<br />
gyrotron working at two frequencies (105 and 140 GHz)<br />
went into operation allowing pure electron heating (ECRH)<br />
and current drive (ECCD). These versatile heating methods<br />
allow the effects of heat, particle and momentum deposition<br />
on energy and particle transport, MHD stability and fast particle<br />
physics to be separated.<br />
Stationary discharges with up to 10 s flat-top allow steady<br />
state investigations not only on the transport and MHD time<br />
scales but also for up to 10 current diffusion times. The fast<br />
integrated control and data acquisition system (CODAC) is<br />
specially adapted to ITER needs with its machine-independent<br />
design, its integrated discharge scenario control and protection<br />
functions and the large number of real-time diagnostics<br />
with integrated data analysis.<br />
The cause of the malfunction leading to serious damage of<br />
the flywheel generator EZ4 (supplies a part of the poloidal<br />
field coils and heating systems) was resolved in 2006. The<br />
repair of the generator runner and flywheel is underway, the<br />
stator must be renewed and completion is scheduled for<br />
October 2008. This accident has given rise to check and to<br />
substantially improve the safety installations of all three<br />
generators. An additional brake for generator EZ2 was constructed<br />
till spring <strong>2007</strong>, followed by an upgrade of the EZ3<br />
brake system at the end of <strong>2007</strong> (section 3.1). The operation<br />
of AUG in <strong>2007</strong> with the remaining generators EZ2 (for the<br />
TF coils) and EZ3 (poloidal field coils and heating systems)<br />
was advanced towards acceptable restrictions by optimized
use of generator power consumption applying lower PF coil<br />
voltages reducing inductive loads and new shape and scenario<br />
evolution accounting better for PF coil interactions. Plasma<br />
currents up to 1 MA at limited triangular plasma shapes,<br />
heating powers up to 7.5 MW and flattop times of more than<br />
5 s were achieved.<br />
In spring <strong>2007</strong> the transition of the AUG vessel to fully<br />
tungsten coated plasma facing surfaces (PFCs) was completed<br />
with the 200 μm W-cladding of the lower outer divertor target<br />
tiles. Careful cleaning of all other tiles was performed to remove<br />
old carbon and boron layers. Accordingly the main emphasis<br />
of the <strong>2007</strong> experimental campaign was on the operation in<br />
an all-metal machine. The proposals were prioritized into W<br />
compatibility of ITER scenarios, extension of the working<br />
space with a metal wall and other ITER related physics<br />
investigations. Plasma operation was accomplished from<br />
April to July and September to October. We conducted 54 long<br />
shifts at high availability with a total of 1150 pulses (technical<br />
tests, diagnostic calibrations and plasma discharges).<br />
1.2 ITER relevant results in <strong>2007</strong><br />
In April <strong>2007</strong> the restart of AUG was done without prior<br />
boronization as the first divertor tokamak operating with a<br />
full tungsten wall. The reduced generator capacity caused<br />
limitations of transformer flux swing, plasma current, plasma<br />
shaping and heating power. In spite of these tough boundary<br />
conditions, a “milestone” pulse was already achieved six<br />
weeks after the first plasma attempt with a full performance<br />
H-mode discharge at β N =2, confinement factor H 98 =1 and a<br />
density of 70 % of the Greenwald density as in previous H-mode<br />
discharges with boronization. No boronizations were performed<br />
throughout the whole campaign. The W concentration<br />
remained at an acceptable level by using central ECRF<br />
at higher heating powers enhancing the turbulent impurity<br />
transport. Obviously the divertor W source has only minor<br />
influence on the plasma W content, which is mainly determined<br />
by the local influx from the low field side limiters<br />
and the central column. The carbon content of a few per<br />
mille did not decrease further, but the net C deposition in the<br />
inner divertor was strongly reduced. This is important for<br />
the tritium co-deposition problem in ITER, as is the whole<br />
W programme for DEMO where the erosion of low-Z material<br />
and the destruction of graphite under neutron bombardment<br />
will be unacceptable (section 2).<br />
The use of ICRF heating is restricted with tungsten walls<br />
by W sputtering caused by accelerated light impurities in<br />
the ICRF antenna near-fields. Therefore the beneficial effect<br />
of ICRH for suppression of W accumulation is offset under<br />
un-boronized conditions. Simulations show an important<br />
influence of the antenna geometry and the resulting box<br />
currents on these electric fields, which will be checked in<br />
2008 after the installation of covering metal corner plates<br />
on one of the antennas.<br />
ASDEX Upgrade<br />
4<br />
During the last years on ASDEX Upgrade the physics base<br />
for ITER operation was significantly extended in both the<br />
foreseen standard H-mode scenario as well as the stationary<br />
improved H-mode (ITER Hybrid) scenario. The progress was<br />
slowed down in <strong>2007</strong> in favour of the tungsten experiments.<br />
Concerning anomalous transport, zonal flows, geodesic acoustic<br />
modes and turbulence k-spectra were investigated by<br />
Doppler reflectometry (section 6.1-6.2). New insights were<br />
gained on the interaction of energetic particles (produced by<br />
ICRH) with TAEs and other modes driven by the fast ions<br />
based on new diagnostics (fast ion loss detectors, SXR, fast<br />
ECE, hopping millimetre-wave reflectometer (from IST),<br />
CO 2 laser) and theoretical tools (section 6.3-6.6). The structures<br />
of ELM produced filaments, pellet ELM triggering,<br />
wall heat loads from ELMs and disruptions, fuel retention in<br />
W surrounding, and disruption mitigation by a fast gas puff<br />
valve close to the plasma have been looked at (section 7).<br />
1.3 Technical Enhancements and Programme in 2008<br />
The restart of AUG is planned for February 2008, again<br />
without boronization and with the main emphasis on reactor<br />
relevant scenarios in an all-metal machine. Assessment of<br />
plasma performance, divertor properties, C retention, erosion,<br />
hydrogen and noble gas balance and operation without intrinsic<br />
C radiation are the main themes. Improved H-modes<br />
at low ITER-like collisionality (may need the revival of<br />
boronizations) and at high densities will be possible with the<br />
increased power from EZ3 extending our operational window.<br />
At the start of the new campaign the EZ3 generator current<br />
will be enhanced providing an increase from 144 MVA to<br />
175 MVA. With the EZ4 flywheel back in operation in<br />
October 2008 and with the experience gained last year the<br />
AUG operation will be boosted into shaped plasma operation<br />
with up to 1.6 MA and more than 20 MW heating power<br />
at pulse lengths lasting for 10 s. This is supported by reliable<br />
tokamak operation including NTM stabilization, ELM and<br />
disruption mitigation. For the 2008 AUG campaign 171 experimental<br />
proposals have been submitted by 84 scientists,<br />
with more than 50 % from outside <strong>IPP</strong> and including 44 ITPA<br />
joint experiments. A prioritized programme was approved by<br />
the AUG PC and will be conducted by new TF leaders including<br />
one from the UKAEA.<br />
In order to achieve AUG´s programmatic goals and to maintain<br />
a leading position parallel to the ITER construction, it is<br />
necessary to continuously upgrade the AUG diagnostic and<br />
technical systems (section 4). The successful H-mode operation<br />
with an all-tungsten wall has set a milestone. The preparations<br />
of the next major hardware extensions are well<br />
underway with support from other EU Associations. Fast ion<br />
loss detectors for the poloidal distribution of fast ions, CTS<br />
(from RisØ) and beam fluctuation measurements (from HAS)<br />
are the next new diagnostics. The tube geometry of the<br />
blower gun extending the pellet ELM-triggering capability
to frequencies of 140 Hz was optimized. Our ECRF system<br />
is presently being upgraded in power (4 MW provided by<br />
4 gyrotrons), pulse length (10 s) and large deposition variability<br />
(tuneable frequency 105-140 GHz, toroidally and real-time<br />
poloidally steerable mirrors). The first 2-frequency gyrotron<br />
has demonstrated reliable long-pulse operation and substantially<br />
contributed to our results. Central heating, suppression<br />
of NTMs and diagnostic support are the main aims.<br />
The installation of a very flexible and powerful system (toroidal<br />
mode number n≤4) of 24 active in-vessel coils will allow<br />
ELM suppression, tearing mode and rotation control (e.g.<br />
locked mode avoidance). The first 16 coils should be installed<br />
in 2009/10. In connection with a conducting shell structure<br />
they will open up the road for resistive wall mode stabilization.<br />
In the mid term range we will focus even more on advanced<br />
tokamak operation. Reliable creation and sustainment of<br />
optimal current and shear profiles requires an additional offaxis<br />
current drive method such as LHCD with about 4 MW<br />
installed power at AUG. First studies compromising accessibility<br />
and current drive efficiency reveal a driven current<br />
of up to 0.4 MA and the possibility of fully non-inductive<br />
CD at I p =1 MA.<br />
2 Operation with complete W covered first wall<br />
2.1 Preparation of an all-W device<br />
The area of W plasma facing components (PFC) has been<br />
continuously increased since 1999. As the last step to a complete<br />
W coverage of the PFCs, the strike point area of the<br />
lower divertor, the horizontal frames of the ICRF antennae<br />
and all protection tiles for diagnostics were exchanged with<br />
Figure 1 a): View into the outer divertor. The strike point tiles are coated<br />
with a 200 μm VPS W layer, the baffle tiles with a 4 μm PVD W layer. The<br />
Langmuir probes are manufactured from bulk W. b): ICRH antenna with<br />
W-coated protection limiter and striped long-term marker probes (Al, Ni,<br />
Mo and W coatings).<br />
ASDEX Upgrade<br />
5<br />
W-coated tiles. At the strike point position of the outer<br />
divertor W VPS (vacuum plasma spray, 200 μm) coatings<br />
were used in order to ensure an erosion lifetime of several<br />
campaigns. The inner strike point area, as well as the tiles installed<br />
in the main chamber, has been W PVD (physical vapour<br />
deposition) coated with a nominal thickness of 4 μm, similar<br />
to other main chamber PFCs coated in earlier campaigns.<br />
Figure 1 shows photos of newly W-coated areas. In the left<br />
upper part the strike point and the baffle of the outer lower<br />
divertor can be seen, which are equipped with flush mounted<br />
Langmuir probes implemented with W bulk material. The<br />
right picture shows an ICRH frame. The new W-coated limiter<br />
tiles (top and bottom of the frame) are clearly distinguishable<br />
by their brighter appearance. The two striped tiles at the left<br />
and the right side of the limiter frame are long-term marker<br />
probes with Al, Ni, Mo and W coatings.<br />
In order to further minimize the carbon content of the surfaces,<br />
as well as to demonstrate operation with bare W surfaces,<br />
the major part of the previously W-coated tiles were<br />
removed and cleaned mechanically as well as in an ultrasonic<br />
bath. The efficiency of the cleaning was investigated with a<br />
scanning electron microscope. The dominant species in the<br />
(un-cleaned) surface layer were boron, carbon and oxygen in<br />
line with earlier Rutherford back-scattering, nuclear reaction<br />
analysis and secondary ion mass spectroscopy analyses. In<br />
contrast, W is clearly dominating the surface composition<br />
on a cleaned W tile with some contribution of C and minor<br />
amounts of B and O in grooves, holes and arc tracks.<br />
2.2 Start-up with un-boronized W-PFCs<br />
Boronizations were regularly performed to access and to<br />
explore a large operational working space. Each boronization<br />
strongly suppresses the contents of medium-Z impurities<br />
and W (1-2 orders of magnitude).<br />
The reduction of W influxes and the temporal evolution of<br />
the boron coverage are especially evident in ICRH dominated<br />
discharges. The effect of boronization at the ICRF limiters is<br />
only very transient and equilibrium is already reached after<br />
20 discharges. Other areas show longer time constants for<br />
recovering the full W influx but, judging from W influx and W<br />
concentration measurements, a global equilibrium is reached<br />
after about 100 discharges, being less than the typical separation<br />
in-between boronizations of about 200 discharges.<br />
The observed time constants for B erosion and W recovery<br />
are also consistent with estimates on B erosion based on<br />
measured deuterium fluxes and B layer thicknesses. However,<br />
in order to verify these estimations and to allow for<br />
undisturbed D retention studies in W it was decided to startup<br />
without boronization.<br />
After pump-down, the machine was baked at 150 °C for 10<br />
days, which is twice the duration of the usual procedure. In<br />
order to further reduce the absorbed water and nitrogen<br />
from the surfaces, several overnight glows in He (partly with
an admixture of 10 % D 2 ) were performed. The start-up<br />
procedure was slower than usual, because of the technical<br />
constraints (due to the missing fly-wheel generator EZ4)<br />
and a less reliable plasma breakdown and current ramp-up<br />
phase compared to boronized conditions. However, after<br />
about 20 plasma discharges the current flat-top could be<br />
reached and it took only about 5 more discharges to obtain<br />
the first H-modes.<br />
He Conc. (Div) (%)<br />
H98<br />
6<br />
4<br />
2<br />
0<br />
1.2<br />
0.8<br />
0.4<br />
0.0<br />
21700 21800<br />
shot<br />
21900<br />
Figure 2: Temporal evolution of the divertor He/D influx ratio (top) and the<br />
ITER H factor H98 (bottom) in I =0.8 MA, P =7.5 MW discharges. The<br />
p NBI<br />
vertical dashed line denotes the discharge from which on He-glow was no<br />
longer performed.<br />
Figure 2 shows the temporal evolution of the divertor He concentration,<br />
and the ITER H factor H98 during I p =0.8 MA,<br />
P NBI =7.5 MW discharges, starting with # 21700 (the re-commissioning<br />
started around # 21600, but mostly technical trials<br />
were performed and only about 100 s of plasma operation<br />
were accomplished in this initial phase). Although the H<br />
concentration was already quite low (~10 %) and the total<br />
radiation was in the range of 50 %, the confinement remained<br />
at H factors between 0.6-0.8. In parallel, an increasing amount<br />
of He was observed in the plasma discharges, obviously<br />
due to the He overnight glows and the inter-shot He glow<br />
discharges (5 min. duration). Since it is known from experiments<br />
and code calculations that He is de-enriched in the<br />
divertor by a factor of 0.25-0.35, the He concentrations in<br />
the main plasma could have reached values up to 20 %,<br />
consistent with exploratory CXRS measurements. The storage<br />
in and the strong release of He from W surfaces was already<br />
ASDEX Upgrade<br />
6<br />
known from the previous campaign and from accompanying<br />
laboratory experiments, but no strong influence on the confinement<br />
was expected. However, after omitting He glow<br />
completely and performing 3 minutes of D 2 glow only after<br />
disruptions, the He concentrations decreased rather quickly<br />
and, concomitantly, the confinement increased (figure 2,<br />
bottom). Edge density and temperature measurements suggested<br />
that a weak edge transport barrier was at least partly<br />
responsible for the lower confinement with high He content.<br />
Additionally, after the initial conditioning phase it was<br />
found, that inter-shot glow discharges are much less important<br />
for plasma ramp-up and density control, than they have<br />
been with graphite PFCs.<br />
Astonishingly, similar levels of oxygen as in previous campaigns<br />
have been achieved after the initial conditioning<br />
phase with the full W wall without boronization. Post<br />
mortem analysis of the PFCs revealed very low C deposition<br />
at remote areas in the divertor (see MF section), which<br />
reflects the strongly reduced primary C sources. However,<br />
neither C influx measurements at the central column nor<br />
CXR spectroscopy show this strong reduction yet. Typical<br />
values are several 10 20 /s for the gross C-influx and 0.3 % for<br />
the edge C concentration. The reason for the persisting (low)<br />
C influx and content is not yet completely understood, but in<br />
principle it can be explained by the remaining small C<br />
sources and the observed strong C recycling. Therefore, all<br />
PFC has been thoroughly cleaned to start the 2008 campaign<br />
with pure W surfaces.<br />
2.3 Tungsten Influxes<br />
Special emphasis is given to the determination of the tungsten<br />
influx in order to elucidate the details of the erosion processes<br />
and to assign them to specific plasma scenarios. Figure 3<br />
shows the temporal evolution of the W influx at the low<br />
field side limiters, the central column and in the divertor in<br />
an I p =0.8 MA, n e ~7.5⋅10 19 /m³ discharge with continuous<br />
NBI and ECRH as well as alternately switched ICRH.<br />
Simultaneously, the outer radius of the plasma was varied.<br />
The W fluxes from the divertor and the central column (HS)<br />
presented in the bottom part of the figure were calculated<br />
assuming toroidal symmetries. The W influx at the low field<br />
side (LFS) ICRH limiter (W L34 ) increases immediately by<br />
almost one order of magnitude as soon as the corresponding<br />
antenna is powered and it increases generally for larger plasma<br />
radii leading to a smaller gap between separatrix and LFS<br />
limiters. From the temporal behaviour of c W it can be concluded<br />
that the divertor W source, although it is the largest<br />
one compared to the sources from the other areas has only a<br />
minor impact on the W contamination in the plasma. This is<br />
in line with earlier investigations comparing discharges with<br />
the upper W divertor with ones using the lower graphite<br />
divertor and dedicated experiments with W injections at the<br />
mid-plane and in the divertor.
P heat/rad (MW)<br />
W mhd (MJ)<br />
Γ (W-atoms/s)<br />
6 PNI<br />
4<br />
2<br />
0.6<br />
0.4<br />
0.2<br />
c w 10<br />
-4<br />
10 -5<br />
10 -6<br />
10 19<br />
10 18<br />
Prad<br />
PICRH34<br />
Wmhd<br />
WODIV<br />
WL34<br />
PECRH<br />
PICRH12<br />
WHS<br />
# 22247<br />
Rout (req.)<br />
Rout (meas.)<br />
2.0 2.5 3.0 4.0 4.5 5.0<br />
Time (s)<br />
The W influx from the divertor is monitored with high spatial<br />
and temporal resolution allowing ELM resolved measurements.<br />
For high density, low temperature divertor conditions most<br />
of the W erosion fluency (>70 %) is observed during the<br />
ELMs, whereas this fraction drops to about 50 % at higher<br />
divertor temperatures. The deduced sputtering yields show,<br />
that similar to the main chamber the W erosion is dominated<br />
strongly by low-Z impurities.<br />
ASDEX Upgrade<br />
2.18<br />
2.16<br />
2.14<br />
Figure 3: Temporal evolution of edge W concentration (c ) and W influxes<br />
W<br />
(Γ) in a discharge with steady state NBI and ECRH and pulsed operation of<br />
the ICRF antenna pairs 1,2 (P ) and 3,4 (P ) and a scan of the<br />
ICRH12 ICRH34<br />
outer plasma radius (R ) out<br />
W conc. @ 1 keV<br />
10 -3<br />
10 -4<br />
10 -5<br />
med. gas, low ECRH<br />
high gas<br />
low gas<br />
medium gas<br />
10<br />
2.0 2.2 2.4 2.6<br />
time / s<br />
-6<br />
rad. peak. / rel. u.<br />
20<br />
10<br />
med. gas, low ECRH<br />
low gas<br />
medium gas<br />
high gas<br />
0.5<br />
0<br />
2.0 2.2 2.4<br />
0<br />
2.6<br />
time / s<br />
Figure 4: Evolution of tungsten (edge) concentrations, radiation peaking<br />
and stored energy (Wmhd) for discharges with different gas puff levels or<br />
different central ECRH<br />
1<br />
R out (m)<br />
Wmhd / MJ<br />
7<br />
2.4 H-mode operation space<br />
The complete coverage of the first wall with tungsten<br />
caused a reduction of the H-mode operation space in terms<br />
of minimum required values of gas puffing and central heating.<br />
To avoid central tungsten accumulation, higher central<br />
ECRH power was required to allow for a reduction of the<br />
gas puff during H-modes. Figure 4 shows time traces of four<br />
1 MA discharges with different levels of gas puffing and<br />
central ECRH (H98=1 at t=2 s). The cases with reduced<br />
ECRH power or too low gas puff exhibit central radiation<br />
peaking, followed by central tungsten accumulation and a<br />
loss of good H-mode confinement. The accumulation of<br />
tungsten is supposed to be a complicated interplay of neoclassical<br />
inward drift, density peaking and central radiation<br />
losses. Probably due to the reduced heat flux causing reduced<br />
anomalous transport, the increase of central radiation due to<br />
tungsten supports electron density profile peaking, as shown<br />
in figure 5. The density profile peaking in turn drives the<br />
neoclassical accumulation of tungsten in the centre.<br />
n e /m -3<br />
1.5·10 20<br />
1.0·10 20<br />
0.5·10 20<br />
low gas<br />
high/med. gas<br />
med. gas, low ECRH<br />
t=2.5 - 2.55 s<br />
0<br />
0 0.2 0.4 0.6 0.8 1<br />
ρ<br />
pol<br />
Figure 5: Density profiles corresponding to the discharges presented in<br />
Figure 4<br />
2.5 Operation of ICRH<br />
In previous campaigns the ICRH was a routine tool to control<br />
the central W accumulation, because of its high flexibility<br />
for operation at different Bt (2.0 T-2.7 T), but operation of<br />
the ICRF antennas in the full tungsten machine appeared to<br />
be difficult without boronization due to W release from the<br />
PFCs. The quite high levels of low-Z impurities can be considered<br />
as most unfavourable conditions for ICRF operation.<br />
The values of the effective sputtering yields during ICRF<br />
heating can be reduced significantly only in the discharges<br />
with high gas puff rates and large clearance between the<br />
plasma and the first wall. These conditions correspond to<br />
low plasma temperature at the edge. By using ICRF heating<br />
only, type III ELMy H-mode is achieved with radiated
power in the range of 80-90 % of ICRF power. Measurements<br />
of W fluxes indicate antenna limiters as dominant<br />
sources of sputtered W during ICRF. This stresses the role of<br />
antenna near-fields in the W sputtering via rectified sheath<br />
potential. Simulations of the near-fields in a vacuum with<br />
fine geometrical details with the HFSS (High Frequency<br />
Structure Simulator) code are in progress. The simulations<br />
show an important role of the parasitic antenna box currents<br />
on the voltages along magnetic field lines. The contribution<br />
to the voltages shows strong dependence on the antenna limiter<br />
geometry which might require optimization. The role of the<br />
box currents is to be checked in experiments in 2008 after the<br />
installation of covering corners on one of the antennas.<br />
3 Technical Systems<br />
In <strong>2007</strong>, for the first time, experiments in a tokamak with a<br />
full tungsten first wall were performed.<br />
The experiment was in operation for 59 days (including 7 technical<br />
shot days) performing 1104 shots in total with 476 shots<br />
useful for the physics programme, which focussed on the<br />
investigation of plasma-tungsten interaction without boronization<br />
of the first wall. Vessel conditioning was performed by<br />
extended backing and glow discharge cleaning. There was no<br />
unscheduled opening in <strong>2007</strong>. Nitrogen venting necessary to<br />
calibrate the Thomson scattering diagnostic was used for a<br />
minor readjustment of the divertor manipulator. The shutdown<br />
periods in winter 2006/07 and autumn <strong>2007</strong> were used for diagnostic<br />
improvements and upgrades, in particular bolometer,<br />
pressure gauges and the relocation of the killer gas valve.<br />
Inspection of the in-vessel components during the scheduled<br />
opening in autumn <strong>2007</strong> revealed an excellent state of the first<br />
wall components. The strike line targets were undamaged.<br />
Small amounts of damage were observed at the outer corners<br />
of the roof baffle. Significant arc tracks were found at the transition<br />
and retention module of the inner divertor. The carbon<br />
deposition on first wall components was below a monolayer.<br />
In preparation for the 2008 campaign, the first wall was cleaned<br />
with wet wiping cloths to remove carbon and boron layers.<br />
3.1 Flywheel generators and power supplies in <strong>2007</strong><br />
For ASDEX Upgrade, flywheel generator EZ2 (167 MVA,<br />
1450 MJ stored energy) supplies the toroidal field coils,<br />
while generators EZ3 (144 MVA, 500 MJ stored energy) and<br />
EZ4 (220 MVA, 650 MJ stored energy) supply the poloidal<br />
field coils and additional heating systems. Due to an incident<br />
with EZ4, this generator is under repair until the second half<br />
of 2008. A special working group for “the safe operation of the<br />
generators at <strong>IPP</strong>”, with specialists from energy supply and<br />
tokamak operation, now co-ordinates the upgrades required to<br />
ensure safe operation of EZ2, EZ3, including the infrastructure,<br />
and to oversee the repairs of EZ4. One example is the installation<br />
of additional independent brakes for EZ2 and EZ3.<br />
ASDEX Upgrade<br />
8<br />
With EZ3 alone, a naïve transfer of all PF and additional<br />
heating circuits which previously connected EZ4 to the<br />
existing connections of EZ3 is not viable, as this would limit<br />
operation to 0.5 MA in H-mode. A critical analysis of the<br />
thyristors used for the poloidal field coils, led to a proposal<br />
to significantly reduce the voltage available to ensure the<br />
best possible use of the thyristors within the limits of EZ3.<br />
Previously, the poloidal field coils were optimised individually<br />
for fast response. With the new configuration, an<br />
acceptable (slower) response to the overall PF set was maintained,<br />
which was tested in July 2006, including the protection<br />
of the generator and power supplies. Successful plasma<br />
operation was obtained with these new settings, starting at<br />
the end of April <strong>2007</strong>. The plasma control systems were<br />
optimized to include the new time constants of the power<br />
supplies. More importantly, all plasma start-up and rampdown<br />
scenarios were modified and unified, to cope with the<br />
severely reduced voltages available for the PF coils.<br />
Figure 6: An example of the power saving with the new power supply configuration<br />
to EZ3. Figure (a) Power requirements for EZ3 without changes<br />
to the thyristor settings, compared to an actual discharge from <strong>2007</strong>.<br />
Figure (b) at the same input power and plasma current.<br />
An example of the power saving with the new power supply<br />
configuration to EZ3 is given in figure 6. Figure 6a shows<br />
the power requirements (filled area in magenta, representing<br />
the sum of EZ3 and EZ4 currents) of a pulse in 2006, prior<br />
to the changes to the thyristor settings (exceeding the limits<br />
for EZ3 alone, already during the pre-charge phase, t10 s can be<br />
achieved. H-modes at 0.8 MA with up to 12 MW additional<br />
heating and H-modes at 1 MA with up to 8.5 MW were possible<br />
in <strong>2007</strong> to investigate the full tungsten wall at ASDEX<br />
Upgrade. Implementation of the physics programme was<br />
however more tedious compared to previous years due to<br />
operation close to the power limits of the EZ3 generator.
3.2 Torus Pumping and Gas Inlet System<br />
To improve the operational reliability, an additional water<br />
cooling pumping system for the torus pumping system was<br />
installed. The type of turbo molecular pump that is currently<br />
in use is no longer supported and so two different types of<br />
pumps were investigated for their suitability as replacements.<br />
Laboratory tests and in-situ operation of both types<br />
during the 2006/07 campaign led to a decision. The contract<br />
for the delivery of 14 pumps (Pfeiffer TPU 2301 PN) was<br />
closed and the first five pumps have already been delivered<br />
and were installed during the shutdown. Due to the modular<br />
design of the control and hardware system it was possible to<br />
replace the pumps and integrate them into the PLC system<br />
without major changes. The gas matrix system for supplying<br />
the discharge gas valves of the Gas Inlet System was commissioned<br />
at the beginning of <strong>2007</strong> and was routinely operated<br />
during the campaign. During glow discharge cleaning GDC<br />
the pressure in the vessel is now feed back controlled. To<br />
reduce the amount of Helium in AUG the gas species usually<br />
used for GDC has been changed from Helium to Deuterium.<br />
Because of the in vessel cryopump with its high pumping<br />
speed for D 2 , the implementation of a new aligned operation<br />
procedure was necessary. For safety reasons this procedure<br />
is automated with a PLC system to ensure that the amount of<br />
Deuterium is always below the allowed threshold.<br />
A new type of electrode for glow discharge, originally<br />
developed for W7-X, was tested in preparation for installation<br />
in AUG. The original anode material was changed from<br />
carbon to tungsten-coated carbon in accordance with the full<br />
tungsten wall. The modified anode was installed in addition<br />
to the existing four anodes. Tests should prove the applicability<br />
of the principle. The new design with a much smaller<br />
footprint compared to the currently used electrodes would<br />
be of great advantage, especially in terms of the planned invessel<br />
coils and conducting wall.<br />
3.3 Data acquisition and computer infrastructure<br />
A high definition video conference system (LifeSize Room<br />
Sony HD together with a KEM 970 based audio system) has<br />
been put into operation in the ASDEX Upgrade control room<br />
to provide the infrastructure for remote experimental participation.<br />
This technology not only enables European and non-<br />
European Associations to fully participate in local experiment<br />
sessions but also allows AUG to participate in other<br />
experiments worldwide. Figure 7 shows an experiment session<br />
between Garching and JT60U in Naka, Japan. It demonstrates<br />
that the feeling between the parties of being present<br />
and involved with each other has definitely improved. In fact<br />
HD video conferencing implements a new quality in working<br />
together over long distances and considerably improves<br />
the co-operative creativity of participating scientists.<br />
For real time data acquisition purposes a new serial I/O card<br />
has been developed which will allow a broad variety of<br />
ASDEX Upgrade<br />
9<br />
external devices to be directly coupled to computer cPCI and<br />
cPCIe busses. This card is part of a hard- and software concept<br />
which has been defined to support RT DAQ and subsequent<br />
RT Analysis and to deliver diagnostic results into the<br />
AUG Control system for advanced plasma control scenarios<br />
like the MHD identification and stabilization initiative.<br />
Figure 7: Video conferencing (AUG/JT60-U) during an experiment session<br />
3.4 Neutral beam heating<br />
During the <strong>2007</strong> campaign neutral beam injection (NBI)<br />
was provided for 503 out of the 563 discharges classified as<br />
“useful”, underlining the NBI’s role as a workhorse among<br />
the heating systems. Operation of the NBI system was mainly<br />
restricted by the power limitations due to the absence of the<br />
EZ4 flywheel generator in this campaign. Of the 20 MW<br />
installed heating power, supplied by two injectors with four<br />
ion sources each, only up to 10 MW were injected. Additionally,<br />
being not fully conditioned, one of the sources of<br />
the first injector was not operable.<br />
Overall, the systems worked reliably with only the loss of<br />
one RF generator in September. A coil had overheated<br />
because a defective component had led to a permanent<br />
power output of the RF system. The secondary damage<br />
caused by the incident included a shortcut in the 110 m long<br />
RF wire between the generator and ion source and a thermal<br />
deformation of the source’s RF transformer. Repairs were<br />
begun immediately and operation of the respective source<br />
was resumed on the 27 th of September. As a consequence for
the future, a new safety interlock was introduced which<br />
switches off the RF system in case of an unrequested power<br />
output. Whenever the limited time between shots allowed,<br />
conditioning of source no. 2 was continued. This source had<br />
been installed close to the end of the previous campaign as a<br />
replacement for a source which had suffered a water leak.<br />
At the beginning of the <strong>2007</strong> campaign, the source’s extraction<br />
grid system was in a completely unconditioned state.<br />
After about 1300 conditioning shots at the end of the campaign<br />
the source could be operated more or less reliably at<br />
40 kV, where 60 kV is the standard operation voltage of this<br />
injector. Conditioning is expected to be finished during the<br />
2008 campaign.<br />
In the following two months shutdown phase maintenance<br />
of both injectors could be finished in due time for the start of<br />
the next campaign despite an extensive list of tasks. Among<br />
them, all eight titanium evaporator pumps were overhauled.<br />
Traces of melting were discovered on bellows of the cooling<br />
connections to the ion dumps of the second injector. The<br />
bellows were replaced and protection shields installed.<br />
3.5 Ion Cyclotron heating<br />
The ICRF system was ready when ASDEX Upgrade restarted<br />
operation. Now all antennas are equipped with W-coated<br />
limiters. One antenna has an optically closed Faraday<br />
screen, to investigate the influence of shielding the antenna<br />
from plasma, possibly expelled by ELMs into the antenna,<br />
on its voltage standoff capability. One antenna has also been<br />
fitted with the option to locally inject gas and with diagnostics<br />
to measure currents drawn by some limiters. Whereas<br />
experimentation with ICRF has become more difficult, a way<br />
was found to still use ICRF efficiently to heat high density<br />
discharges centrally: a large plasma-antenna distance is beneficial,<br />
together with a high gas puff rate. In terms of plasma<br />
and impurity behaviour, there is no difference between<br />
standard gas puff and local gas puff near the antenna. The<br />
latter however has the advantage that it increases the antenna<br />
coupling resistance, which is low at a large antennaplasma<br />
distance.<br />
One of the power tetrodes failed during operation, increasing<br />
the need to find a solution for the unavailability of replacement<br />
tetrodes. While this tetrode is being refurbished, the<br />
ICRF systems have to operate without any spare tetrode.<br />
The failure of another tetrode would result in a reduction of<br />
the available power by half. The option to modify the generators<br />
to be able to use commercially available tetrodes is<br />
being investigated.<br />
During the AUG vessel opening at the end of the year, diagonal<br />
plates covering the uncompensated top and bottom<br />
parts of the antenna straps have been installed. Calculations<br />
show that the dominant contributions to the electric fields are<br />
due to currents in the antenna box. Consequently, this installation<br />
should not lead to a substantial change in impurity<br />
ASDEX Upgrade<br />
10<br />
production, as long as the fields due to the antenna box<br />
remain the major contribution. Our modelling also shows<br />
that those dominant fields can be reduced, by placing the<br />
antenna in a wall and by having 4 straps with the proper<br />
phasing, rather than 2. A new vacuum chamber, where such<br />
a 4-strap antenna can be tested, was ordered for the new test<br />
facility located in the L7 hall. The contract for the automatic<br />
matching was cancelled as it became clear that the company<br />
that had been working on it since 2000 could not fulfil its<br />
obligations. Alternative options are being investigated. A<br />
complete overhaul of the compressor system providing pressurized<br />
air for the transmission lines is ongoing. It will allow<br />
for faster refilling of those lines and easier maintenance.<br />
3.6 Electron Cyclotron Resonance Heating<br />
In <strong>2007</strong> both ECRH systems were routinely requested for a<br />
large number of ASDEX Upgrade pulses. The main drive<br />
for the use of ECRH was the prevention of central accumulation<br />
of tungsten (see section 2). The old system was back<br />
to full power (i.e. 1.6 MW, 2 s or 0.8 MW, 4 s) after a gyrotron<br />
broken in 2004 was replaced in the last shutdown by a<br />
similar tube, formerly used at W7-AS.<br />
In February <strong>2007</strong> the new 2-frequency gyrotron Odissey-2<br />
was commissioned. The achieved maximum output power<br />
was 910 kW at 140 GHz and 650 kW at 105 GHz, both for<br />
10 s. Using the new gyrotron, the new stainless-steel highpower<br />
long-pulse load from GYCOM has been conditioned<br />
rapidly and has operated very reliably since then. With<br />
140 GHz the gyrotron was used routinely for heating (700 kW,<br />
limited by arcing in torus-side mirror box, for 5 s, limited by<br />
plasma duration). With 105 GHz, first experiments for collective<br />
Thomson Scattering were performed with the new<br />
RisØ-System which receives its signal through the transmission<br />
line of unit 2. The extension of the new ECRH-2 system<br />
with three 4-frequency gyrotrons 105-140 GHz/4×1 MW/10 sec<br />
is ongoing. First short-pulse tests of the modified gyrotron<br />
Odissey-1, which has been equipped with a BN-Brewster<br />
window, were performed at GYCOM up to 1 MW/0.8 MW<br />
at 140 GHz/other frequencies. No arcing on the air-side was<br />
observed, proving the viability of the concept. Actually the<br />
BN-window has been replaced by a diamond window. Final<br />
factory tests are expected soon. For details on the future<br />
planning for the new system see section 4.<br />
4 AUG enhancements<br />
Continuous progress in tokamak research needs hardware<br />
upgrades that enhance the machine’s capabilities into new<br />
directions, according to recent theoretical and experimental<br />
findings. In line with its mission to prepare for ITER,<br />
ASDEX Upgrade is presently being equipped with new<br />
tools that will enable active control of MHD modes both in<br />
the plasma core (sawteeth, NTMs) as well as in the edge
(ELMs, RWMs). In the first area, the upgrade of the ECRH<br />
system from 2 MW to 6 MW at 140 GHz, including multifrequency<br />
capability in the new system, is underway EU<br />
preferential support activity, see also last year’s report). This<br />
system will also allow global profile shaping. Below, we<br />
report on this year’s developments aimed at preparing feedback<br />
controlled deposition using the fast movable mirrors<br />
installed during the upgrade.<br />
In the second area, phase I EU preferential support has been<br />
awarded to stepwise enhance the machine’s capabilities<br />
adding in-vessel coils that can produce helical fields. While<br />
a first step is aimed at ELM control with static perturbation<br />
fields, the later steps include rotating perturbation fields for<br />
interaction with tearing modes and, after the installation of<br />
passive conducting structures close to the plasma, also with RWMs.<br />
The enhancements will become available in a stepwise manner<br />
from 2008 to 2011, allowing new experimental possibilities<br />
in the following years up to ~2015. In addition to the two<br />
enhancements described here, a continuous refinement of<br />
diagnostics is taking place. Furthermore, a conceptual design<br />
has been started together with CEA to explore possibilities<br />
for LHCD on ASDEX Upgrade, which would allow substantial<br />
current profile control together with testing of technological<br />
concepts such as a PAM launcher under ITER relevant<br />
edge conditions.<br />
4.1 ECRH extension and real time MHD control<br />
The ECRH system on ASDEX Upgrade is being extended by<br />
four 1 MW, 10 s multi-frequency units (see section 3.6) in<br />
cooperation with IAP Nishny Novgorod, IPF Stuttgart and<br />
FZ Karlsruhe. New launchers allow fast poloidal steering<br />
during discharges to vary the location of heating and current<br />
drive. One of the main goals of the new system is real-time<br />
control of MHD modes. For this purpose real-time control<br />
of the mirror drivers has to be developed which will allow<br />
the power to be deposited on the respective resonant flux<br />
surfaces, mainly for (2,1)-, (3,2)-NTMs and sawteeth. For<br />
this purpose, new data-acquisition systems for several diagnostics<br />
have been set up and a new structure for real-time<br />
data processing is being developed according to the foreseen<br />
control scheme.<br />
The presence and type of mode is determined by fast magnetic<br />
signal analysis.<br />
The relevant magnetic flux surface is found either by using<br />
fast ECE data or real-time equilibrium reconstruction. Both<br />
tracks are followed: a real-time-capable 60-channel 2-MHz<br />
ECE data acquisition system has been set up. Real-time correlation<br />
analysis of channels including the mode signal from the<br />
fast magnetics is planned. Real-time magnetic diagnostics,<br />
acquiring 75 channels of magnetic probe, flux loop and coil<br />
current data at 10 kHz are in operation. Reconstruction of the<br />
magnetic geometry using function parameterization (FPP)<br />
with a cycle time of 1.1 ms for 20 principal components has<br />
ASDEX Upgrade<br />
11<br />
been achieved. The next step is to include local current profile<br />
information, derived from the MSE diagnostic, recently<br />
upgraded for real-time performance. The output of the ECEand<br />
the FPP analysis will be combined using a Bayesian filter<br />
to get the best guess for the mode location, developed in collaboration<br />
with IPF/Politecnico Milano. In order to deposit<br />
the power onto the identified flux surface, an algorithm is<br />
under development using look-up-tables based on off-line<br />
ECRH beam tracing. The ECRH deposition position can be<br />
controlled independently by modulating the ECRH and<br />
detecting the correlated temperature modulation using ECE<br />
(see figure 8). It is planned to test all components in an open<br />
loop in 2008 and to achieve feedback control in 2009 in line<br />
with the completion of the ECRH system: the second gyrotron<br />
unit is expected to operate in the first half of 2008;<br />
units 3 and 4 will follow in autumn 2008 and spring 2009.<br />
Figure 8: MHD real time control scheme using ECRH<br />
4.2 MHD control with Active Coils and Conducting Wall<br />
The extension of ASDEX Upgrade with in-vessel coils and<br />
conducting wall is being made in several stages, first with<br />
16 coils (stage 1), 8 additional fast midplane coils (stage 2),<br />
12 AC amplifiers (stage 3), conducting wall elements and<br />
active feedback control for resistive wall mode (RWM) stabilization<br />
(stage 4) and, optionally, 12 additional AC amplifiers<br />
for fully individual coil supplies. This extension is<br />
being carried out in collaboration with RFX Padova, KTH<br />
Stockholm and FZ Jülich.<br />
Stationary n=3 and n=2 fields have been found to mitigate/suppress<br />
ELM instabilities. However, the physics of the<br />
effect is unknown to date. The planned coil set is thus designed<br />
for a highly flexible field configuration, e.g. to test<br />
the importance of a resonance between the error field and<br />
rational surfaces in the pedestal region. The toroidal mode<br />
number can be chosen up to n=4, reducing significantly the<br />
parasitic core island size and risk of NTM seeding compared<br />
to n=3. The vacuum field line excursion is reduced from up<br />
to 7 mm for n=3 to 2 mm for n=4 perturbations while maintaining<br />
the same level of ergodisation (Chirikov parameter<br />
σ=3) in the pedestal region (figure 9).
Field line excursion [cm]<br />
1<br />
0.75<br />
0.5<br />
0.25<br />
0<br />
0.2<br />
n=3<br />
n=4<br />
|q|=3/2<br />
0.3<br />
|q|=5/3<br />
0.4<br />
|q|=2<br />
In stages 1 and 2, n=2 and n=4 configurations (each with<br />
four different parity options) are used with a single DC power<br />
supply. In stage 3, 12 AC power amplifiers allow rotating<br />
fields and continuous variation of the poloidal phase. Fast<br />
rotating fields can prevent NTMs from locking to the vessel<br />
wall to delay or avoid disruptions. It is also possible to study<br />
the interaction of modes with the rotating error field, for<br />
example to synchronise the island position with ECCD stabilization<br />
in the O-point. The conducting wall elements in<br />
stage 4 will permit eddy currents to slow down the RWM<br />
growth rate sufficiently for active control. The design work<br />
is supported by 3D stability calculations using the STAR-<br />
WALL code.<br />
The technical design of stage 1 components has been completed.<br />
The upper and lower coils (“B”-coils, see figure 9)<br />
are mounted on the PSL. The winding is embedded in an<br />
epoxy resin and enclosed in a welded thin metal casing for<br />
complete isolation from the plasma. Joule heating by eddy<br />
currents in the casing limits the pulse duration to ~500 Hz at<br />
10 seconds and full rated coil current. For minimum interruption<br />
of ASDEX Upgrade operation, it is planned to install<br />
the B-coils in two successive maintenance periods, in<br />
2009 and 2010. Plasma compatibility tests for an insulating<br />
coil casing for the fast midplane coils are ongoing.<br />
5 Integrated data analysis<br />
|q|=9/4<br />
|q|=2<br />
|q|=7/3<br />
|q|=8/3<br />
|q|=3<br />
|q|=11/4<br />
|q|=5/2<br />
|q|=4<br />
|q|=4<br />
0.5 0.6 0.7 0.8 0.9<br />
normalised poloidal flux<br />
Figure 9: Saddle coils (insert) and field line excursion for n=3 and n=4<br />
The concept of probabilistic data evaluation relies on both a<br />
forward model linking the physical quantities of interest to<br />
the measured data and a statistical model for the measurement<br />
uncertainties and systematic and statistical uncertainties<br />
of model and calibration parameters. The statistical<br />
model provides a measure to prevent over-interpretation by<br />
distinguishing data structures which are due to significant<br />
physical information from structures which are due to statistical<br />
fluctuations (noise) or systematic effects. Physical<br />
ASDEX Upgrade<br />
1.0<br />
12<br />
conditions and prior knowledge about parameters can be<br />
easily applied within a probabilistic approach. The probabilistic<br />
method allows data from single diagnostics to be<br />
consistently and most reliably analysed. Additionally, it is<br />
useful for validation and combination of sets of diagnostics<br />
in a transparent and standardized way. The Integrated Data<br />
Analysis (IDA) approach provides a full probabilistic<br />
model including physical and statistical models of an integrated<br />
set of different diagnostics. The goal of IDA is to<br />
combine data from heterogeneous and complementary<br />
diagnostics to consider all dependencies within and between<br />
diagnostics for obtaining validated and most reliable<br />
results. IDA was applied to i) the determination of the radial<br />
electric field from passive He II emission and ii) the reconstruction<br />
of electron density profiles from Lithium beam<br />
emission spectroscopy in the plasma edge region and from a<br />
combined analysis of Lithium beam and DCN interferometry<br />
data for full density profiles.<br />
5.1 Radial electric field from passive He II emission<br />
This newly developed method is based on passive spectroscopy<br />
of the He II (4→3) transition at 468.57 nm. The optical<br />
head used for these measurements is part of the Lithium beam<br />
diagnostic. Its lines of sight are situated nearly poloidally.<br />
Fibre optics guide the collected light to two Czerny Turner<br />
spectrometers equipped with fast frame transfer CCDs, which<br />
record data from 18 lines of sight with a frame rate of 4 ms.<br />
Figure 10: Analysis of the influence of a wavelength shift on the determined<br />
electric field<br />
In the forward model the spectrally resolved emitted light<br />
along these lines of sight is calculated, taking into account<br />
the relevant atomic processes as well as the various forces<br />
acting on the emitting particles which lead to the diamagnetic<br />
drift and the E×B drift. The projection of the parallel velocity<br />
onto the lines of sight is included. The forward model<br />
relies on the measured profiles of electron density, electron<br />
temperature and the photoemission coefficients which were<br />
determined using the ADAS package. The profiles of He +
density and He + temperature as well as the unknown E r profile<br />
are described with spline parameterizations. The spline<br />
knots are varied until a best fit of the modelled profiles with<br />
the measured profiles within their uncertainties is achieved.<br />
A careful analysis of the influence of all the different input<br />
parameters has been carried out.<br />
Figure 10 shows the reconstruction of E r for different wavelength<br />
calibrations of a weak H-mode just after the L/H transition<br />
(#21181, t=5 s). While the gradient of the E r profile in<br />
the pedestal region as well as the position of the minimum is<br />
unaffected, the magnitude of the E r dip varies strongly with<br />
the wavelength shift.<br />
5.2 Integrated Lithium beam and interferometry data analysis<br />
Electron density profile determination from the lithium<br />
beam (LIB) diagnostic is based on the observation of Li I<br />
radiation at 670.8 nm from neutral lithium atoms injected<br />
with an energy of 15-80 keV into the plasma. The newly developed<br />
probabilistic data analysis tool for the LIB diagnostic<br />
is based on a probabilistic description of the measured spatial<br />
line emission profiles and a forward model (collisionalradiative)<br />
of the simulation of the data for a given density<br />
profile. Since only forward modelling is involved no direct<br />
inversion of the noisy data is necessary. The probabilistic<br />
method has several advantages compared to the conventional<br />
ill-conditioned inversion technique. It is not necessary to measure<br />
the whole emission profile, to fulfil an inner boundary<br />
condition or to provide additional experimental information,<br />
to pre-smooth or bin the data temporally. The cumbersome<br />
numerical problems with the absolute calibration factor are<br />
resolved. The new technique is numerically stable. Consistent<br />
profile uncertainties are provided reflecting all error<br />
sources encountered.<br />
ρ pol<br />
ρ pol<br />
Figure 11: Comparison of the density profiles (#20160) obtained with the<br />
new analysis tool (blue), the classical <strong>IPP</strong> algorithm (green) and the edge<br />
Thomson scattering diagnostics (red). Left: series of density profiles (3.7s-3.9s)<br />
Right: profile and estimation uncertainties for a single time frame with a<br />
temporal resolution of 1 ms.<br />
Figure 11 depicts density profiles of an H-mode discharge<br />
with medium electron density. The pedestal is well resolved<br />
ASDEX Upgrade<br />
13<br />
for the edge Thomson system and the new LIB analysis tool<br />
whereas the old tool does not provide values at the pedestal<br />
top. The reliability of the profile for the medium density<br />
regime is large for ρ pol >0.93. The error bars become large<br />
for ρ pol
as r/a≈0.75, depending on the q profile (i.e. collisionless<br />
Landau damping), with a frequency scale G→√2 consistent<br />
with theory. As the GAM disappears in the core it is<br />
replaced by an enhanced level of background E r fluctuations<br />
– i.e. random shearing. Random fluctuations are also notably<br />
higher in elongated diverted plasmas. Radially the GAM<br />
frequency is not a smooth function but displays a series of<br />
plateaus a few cm wide coinciding with peaks in the GAM<br />
amplitude, suggesting several zonal flow layers. At the plateau<br />
edges the GAM spectral peak splits into two frequency<br />
branches (see figure 13).<br />
Frequency (kHz)<br />
GAM intensity (arb)<br />
25<br />
20<br />
15<br />
10<br />
5<br />
0.3<br />
0.2<br />
0.1<br />
#20787 Ohmic<br />
κ=1.12 q 95 =3.5<br />
ρ = 0.78<br />
f D rms<br />
-2 ρ = 0.95<br />
-3<br />
-4<br />
plateau<br />
1kHz 100<br />
-1<br />
ω = 4πcs/R [(1+κ) −ε]<br />
peak<br />
spliting<br />
ω = √2cs/R<br />
ρ = 0.99<br />
peak x100<br />
0<br />
0.7 0.8 0.9<br />
Radius ρpol 1.0 1.1<br />
Figure 13: GAM frequency and amplitude radial profile for circular limiter<br />
shot #20787<br />
6.2 Turbulence k-spectra<br />
Doppler reflectometry is a diagnostic technique that combines<br />
the positive aspects of scattering and reflectometry<br />
techniques. By tilting the antenna, a specific fluctuation<br />
wavenumber is selected according to the Bragg scattering condition,<br />
k~2k 0 sinθ. Hence a radially localized measurement<br />
of the turbulence wavenumber spectrum can be measured by<br />
scanning the tilt angle θ. A significant upgrade to the<br />
Doppler reflectometry system is a new channel, which has<br />
been commissioned recently. It consists of a steerable antenna<br />
and a W-band reflectometer to extend the radial coverage<br />
into the core. The new antenna configuration allows for<br />
dynamic wavenumber selection up to 25 cm -1 . Using the<br />
new system, turbulence wavenumber spectra were measured<br />
at various radial positions for L-mode and H-mode discharges.<br />
The k-spectra follow power laws k -α with a clear<br />
transition of the spectral index α at kρ s ~1-2 (see figure 14),<br />
which is consistent with measurements reported from Tore<br />
ASDEX Upgrade<br />
14<br />
Supra. Furthermore, a change in the k-spectra is found when<br />
applying electron cyclotron heating compared to pure NBI<br />
heating, indicating a possible change in the underlying turbulence<br />
properties. However, the data is still subject to<br />
ongoing analysis, especially concerning the values of the<br />
spectral indexes.<br />
~ 2 2<br />
|n(k)| /n [a.u.]<br />
1.0<br />
0.1<br />
0.01<br />
0.001<br />
k -2.2<br />
k -7.1<br />
0.0001<br />
0.3 1<br />
k ρs<br />
5<br />
Figure 14: k-spectrum of the density fluctuations |n(k)| 2 normalized to the<br />
squared density as a function of kρ (logarithmic scales) for an H-mode dis-<br />
s<br />
charge (NBI only) at a radial position of ρ ≈0.96 pol<br />
6.3 Rotation frequencies of MHD modes<br />
Plasma rotation plays an important role in understanding<br />
and controlling MHD activity in fusion devices. However, it<br />
is still debatable which physics mechanisms determine the<br />
rotation frequency f 0 of MHD modes in the plasma rest<br />
frame. To this purpose, various assumptions for f 0 were tested<br />
for NTM and TAE modes. The assumptions for f 0 take the<br />
form of different combinations of frequencies derived from<br />
toroidal velocity, poloidal velocity, electron diamagnetic<br />
velocity and E×B velocity.<br />
In the calculation of f 0 , the toroidal rotation is measured by<br />
CXRS, the poloidal rotation is assumed to be neoclassical<br />
(and is calculated by the NEOART code), the diamagnetic<br />
velocity is computed from the electron density and temperature<br />
profiles and the E×B velocity is measured by Doppler<br />
reflectometry, assuming that the phase velocity of the turbulence<br />
is small. For TAEs the frequency f 0 was compared<br />
with theoretical predictions. The rest frame frequencies during<br />
an NTM were found to be small and the rotation to be in the<br />
ion diamagnetic direction when considering only toroidal<br />
and poloidal fluid velocities. However, with the inclusion of<br />
the diamagnetic velocity f 0 decreased to about 0 kHz, indicating<br />
that NTMs have no intrinsic rotation. In the case of<br />
TAE modes, comparison with prediction from theory indicates<br />
that the diamagnetic velocity is not negligible and should<br />
be included in the calculation of the rotation frequency f 0 .
6.4 TAE structure through high resolution SXR<br />
The internal structure of Toroidal Alfvén Eigenmodes was<br />
studied through a new multichord SXR diagnostic with high<br />
resolution. A total of 32 lines of sight span a full poloidal<br />
cross-section, with 2 MHz sampling rate and 0.5 MHz bandwidth.<br />
A detailed knowledge of the TAE internal structure is<br />
crucial to benchmark the existing theories and make reliable<br />
predictions for future experiments. TAEs with toroidal mode<br />
numbers from n=3 to 7 were excited through ICRH. The<br />
SXR measurements show that these modes peak at midradius<br />
and have displacement values in the range 0.1-1 mm, as<br />
can be seen in figure 15 for the n=4 TAE. A good agreement<br />
with predictions of two linear stability codes, the resistive<br />
MHD code CASTOR and the gyrokinetic code LIGKA, is<br />
found, as shown in figure 15. In particular, the radial position<br />
and width of the TAE dominant peak are well reproduced.<br />
A test of the diagnostic sensitivity to changes in the<br />
shape of the TAE eigenfunction was made by simulating the<br />
SXR measurements with the MHD-Interpretation Code in<br />
the real geometry.<br />
Figure 15: (a) Radial eigenfunction of the n=4 TAE in discharge #21067 from<br />
SXR measurements and (b) as predicted by CASTOR and LIGKA simulations<br />
6.5 Fluctuation coherence analysis<br />
The dual-channel fast frequency hopping millimetre-wave<br />
reflectometer is capable of measuring density fluctuations<br />
from the plasma edge to core, allowing the radial eigenfunction<br />
of n=4 TAE to be obtained using phase perturbation and<br />
coherence data analysis techniques. The phase perturbation<br />
analysis indicates the δn e /n e amplitude whereas the<br />
coherence technique gives the relative strength between different<br />
peaks as well as the sign of the radial eigenfunction as<br />
shown in figure 16. The two techniques reveal similar results,<br />
and in particular the radial structure of n=4 TAE is found<br />
to be in good agreement with numerical predictions from<br />
linear gyrokinetic (LIGKA) and resistive MHD (CASTOR)<br />
ASDEX Upgrade<br />
15<br />
simulations. Modes with upward frequency sweeping at<br />
ρ pol ≈0.2-0.4 (+/-0.05) are observed in the early phase of<br />
some discharges with ICRH power ramp-up and are identified<br />
as possible Alfvén Cascades.<br />
Coherence γ<br />
Cross phase θ 0 (rad)<br />
1<br />
0.9<br />
0.8<br />
0.7<br />
0.6<br />
0.5<br />
0.4<br />
0.3<br />
0.2<br />
0.1<br />
0<br />
3<br />
2<br />
1<br />
0<br />
-1<br />
-2<br />
a)<br />
b)<br />
n=5<br />
n=4<br />
-3<br />
0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1<br />
Normalized radius ρpol Figure 16: Coherence analysis: (a) Coherence profile for n=4 and n=5<br />
TAE modes, (b) Cross-phase profile for n=4 TAE mode for shot #21007<br />
6.6 Collective Thomson Scattering<br />
The collective Thomson scattering (CTS) diagnostic uses<br />
mm-waves generated by the newly installed 1 MW dual<br />
frequency gyrotron as probing radiation at 105 GHz.<br />
Figure 17: First back scattered radiation results<br />
1.1
It measures back-scattered radiation using the other ECRH<br />
antenna and transmission line located in the same port. This<br />
information will be used to infer the 1-D velocity distribution<br />
of the confined fast ions.<br />
The figure 17 above shows the first scattered radiation results,<br />
an important milestone for the diagnostic. The centre most<br />
channels are plotted as a function of time during a plasma<br />
discharge where the receiver antenna is swept twice across<br />
the gyrotron beam. The vertical lines are the time points<br />
where the receiver antenna position is expected to have<br />
maximum overlap. The commissioning is in its final stages<br />
and physics exploitation is expected in the 2008 campaign.<br />
6.7 Radial acceleration of solid hydrogen pellets<br />
Fuelling pellets, injected into the plasma from the magnetic<br />
high field side (HFS), undergo a strong radial acceleration<br />
towards the magnetic low field side (LFS), as observed by a<br />
fast framing camera system. The camera images allow for the<br />
study of the pellet velocity through the whole pellet trajectory<br />
inside the separatrix, revealing a monotonic increase of the<br />
acceleration as the pellet penetrates deeper into the plasma.<br />
The cause of this radial acceleration is thought to originate<br />
from a rocket-effect by the asymmetric ablation of the pellet<br />
surface. The ablation asymmetry is the result of the grad B<br />
drift of the pellet cloud, which is then shifted relative to the<br />
pellet. As the pellet cloud provides shelter for the pellet from<br />
hot plasma electrons, the shift of the cloud towards the LFS<br />
will result in a higher heat flux (i.e. a higher ablation rate) at<br />
the HFS of the pellet, thus there will be a net reaction force on<br />
the pellet caused by the impulse of the leaving particles.<br />
Simulations, based on the simple but yet most powerful pellet<br />
ablation model, the NGS (Neutral Gas Shielding), were performed<br />
to estimate the ablation asymmetry. It was assumed<br />
that the total ablation rate is given by the NGS model, but a<br />
small fraction (ε) of it is asymmetrically produced on the<br />
pellet’s HFS. The corresponding net radial force on the pellet<br />
and hence acceleration is taken into account in the simulation,<br />
resulting in curved pellet trajectories similar to the measurements.<br />
Simulations were performed with pellet and injection<br />
geometry settings identical to those in the measurements.<br />
The asymmetry parameter (ε) was tuned until the simulated<br />
pellet trajectory fitted the measured one separately for each<br />
pellet event, and the corresponding value of ε was considered<br />
as the output of the simulation. Up to now 16 pellet events have<br />
been studied and asymmetry values fell in the range of 3-9 %.<br />
6.8 New stochastic model for the sawtooth crash<br />
The sawtooth oscillation is one of the fundamental instabilities<br />
observed in tokamaks. Still no definitive explanation for<br />
the crash process exists. Incomplete sawtooth reconnection<br />
is often observed. It is associated with an internal m/n=1/1<br />
kink mode which does not vanish after the crash phase (as<br />
would be the case for complete reconnection).<br />
ASDEX Upgrade<br />
16<br />
It was shown that these sawteeth cannot be fully described<br />
by a pure m/n=1/1 mode and that higher harmonics play an<br />
important role during the sawtooth crash phase. We demonstrated<br />
that stochastization appears due to the excitation of<br />
low-order resonances which are present in the corresponding<br />
q-profiles inside the q=1 surface which reflects the key<br />
role of the central q(0)-value. Depending on this value two<br />
completely different situations are possible for one and the<br />
same mode perturbations: (i) the resonant surfaces are present<br />
in the q-profile leading to stochasticity and sawtooth crash<br />
(q(0)=0.7±0.1); (ii) the resonant surfaces are not present,<br />
which means no stochasticity in the system and no crash<br />
event (q(0)=0.9±0.05). Accordingly the central safety factor<br />
value is always less than unity in the case of a non-complete<br />
sawtooth reconnection. Our investigations show that the stochastic<br />
model agrees well with the experimental observations<br />
and can be proposed as a promising candidate for an<br />
explanation of the sawtooth reconnection.<br />
6.9 Extrapolation of AUG H-mode discharges to ITER<br />
Scaling laws predict ITER’s confinement and fusion performance<br />
in H-mode. Besides the well established IPB98(y,2)<br />
law, others have been proposed with a weaker β dependence,<br />
such as Cordey’s (2005) and the GyroBohm scaling laws<br />
(see figure 18).<br />
Q/(Q+5)<br />
1<br />
0.1<br />
0.05<br />
IPB98(y,2) Cordey05<br />
0.1 1<br />
3.23 -1.23 -3.10<br />
35.5 H β q<br />
98 N 95<br />
ES GB<br />
ITER ITER<br />
ITER<br />
0.1 1 0.1 1<br />
1.82 0.18 -2.20<br />
6.07 H Cor β N q 95<br />
2.22 -0.22 -2.71<br />
22.8 H EGB β N q95<br />
Figure 18: 0D figure of merit of Q/(Q+5) assuming a constant Greenwald<br />
fraction for the different scaling laws, versus Q/(Q+5) predicted with the 1D<br />
ASTRA simulations. IPB98(y,2) (red), Cordey 05 (green), GyroBohm (blue)<br />
Theory based dimensionless models also predict the ITER<br />
performance. However, even those based on the same instabilities<br />
yield different core predictions. Moreover they are<br />
strongly sensitive to the pedestal density and temperatures,<br />
which are predicted with large uncertainties. In this work<br />
we extrapolate AUG discharges to ITER, using the information<br />
contained in the scaling laws with additional input<br />
from present experiments, in particular the profile shapes,<br />
the H factors, the thermal normalised pressure β N,th and q 95 .<br />
A profile database of 92 well diagnosed H-mode discharges<br />
has been selected, including only stationary time intervals.<br />
The scaled profiles have then been used for ASTRA simulations<br />
with ITER geometry, in order to predict the P fus and P rad ,<br />
as well as P aux needed to obtain the target β N,th at the given<br />
H-factor. The effect of varying the tungsten concentrations<br />
is also investigated here. Dimensionless figures of merit are
validated against the present database, showing that the<br />
profile shape does not dramatically affect the performance;<br />
however, care is required in the choice of the correct figure<br />
of merit, which is strictly related to the assumptions made.<br />
7 Edge and Divertor<br />
7.1 Large and Small Scale Fluctuations<br />
Recently, large scale fluctuations of electron density and<br />
temperature were found at the pedestal in-between ELMs.<br />
They were investigated in detail with edge Thomson scattering.<br />
The fluctuation amplitudes were analysed, varying the density,<br />
heating power, magnetic field, plasma current and shape. It<br />
was found that the relative amplitudes of the inter-ELM<br />
fluctuations increase mainly with increasing line density.<br />
When approaching the Greenwald density (n GW ) at the plasma<br />
edge the mean relative amplitude of the electron density<br />
fluctuations is at about 30 %. The small scale fluctuations of<br />
the electrons in the pedestal were investigated indirectly by<br />
measuring the parameter η e =L ne /L Te with L ne and L Te as the<br />
gradient lengths of the 1D profiles of electron density and<br />
temperature. So far, values for η e around 2 have been found.<br />
By analysing a larger number of plasma discharges with different<br />
discharge parameters it was found that η e increases<br />
for larger elongation (κ), which is expected theoretically:<br />
At κ≈1.35 η e is around 1.2 and rises up to η e ≈2 at κ≈1.8.<br />
The variation of η e with other plasma parameters will be further<br />
investigated experimentally and compared to the results<br />
of theoretical simulations of actual plasma discharges.<br />
7.2 Radial velocity of filaments<br />
Filaments are coherent substructures that form e.g. during<br />
an ELM crash and propagate through the scrape-off layer<br />
towards the vacuum chamber walls, leading to a localized<br />
energy deposition. Various models have been proposed for<br />
their radial propagation. The models differ with respect to<br />
the damping mechanisms and lead to opposed predictions<br />
on the scaling of the radial propagation velocity with the filament<br />
size, i.e. whether bigger or smaller filaments move<br />
faster. The radial and poloidal/toroidal motion of filaments<br />
has been studied with a recently installed filament probe.<br />
The analysis reveals that bigger filaments move faster, with<br />
radial velocities being in the range of a few km/s. This clearly<br />
excludes the sheath damping model, but agrees quite well<br />
with the polarization current model. This finding is important,<br />
as bigger filaments carry a higher energy content, and –<br />
if they move faster and thus have less time to lose their energy<br />
by parallel transport – deposit more heat on the plasma facing<br />
components. Toroidal rotation velocities have been found to<br />
be in the range of up to the pedestal rotation velocity, indicating<br />
that the filaments start with a rotation equal to the<br />
plasma edge and then slow down on their way out. Furthermore,<br />
the filaments broaden with time due to diffusion, and<br />
ASDEX Upgrade<br />
17<br />
lose particles parallel to the field lines with a rate similar to<br />
a free flow of particles. An extrapolation shows that they are<br />
formed with densities close to separatrix densities, indicating<br />
their origin close to the separatrix.<br />
7.3 Pellet ELM triggering<br />
In order to get a deeper insight into the process of ELM triggering<br />
by pellets, pellet injection was analysed in Ohmic,<br />
L-mode and type-III ELMy H-mode discharges, as well as<br />
in ELM-free phases, type-I ELMs in radiative edge scenarios<br />
and the quiescent H-mode regime. In hot edge type-I plasmas<br />
both spontaneous and triggered ELMs are found to evolve<br />
fastest. Reducing the power flux crossing the separatrix,<br />
results in a slowing down of spontaneous ELM growth but<br />
keeps fast rising triggered ELMs.<br />
10 -3<br />
10 -4<br />
10<br />
3<br />
-5<br />
ELM growths time (s)<br />
4<br />
Spontaneous<br />
Pellet triggered<br />
Pedestal top η (10 -8 Ωm)<br />
5 6<br />
Figure 19: ELM growth times versus pedestal top resistivity (parallel<br />
Spitzer). The data comprise hot edge type-I, radiative type-I and type-III<br />
ensembles (left to right), all discharges are at I = 1 MA.<br />
P<br />
This strong effect is shown in figure 19, adopting the increasing<br />
pedestal top resistivity as a measure for the edge<br />
cooling caused by the power flux reduction. The pellet imposed<br />
perturbation is obviously always strong enough to trigger an<br />
ELM in case conditions in the edge barrier regions are prone<br />
to instability growth. The magnitude of the perturbation is<br />
even strong enough to push the triggered mode into the<br />
regime of nonlinear explosive growth. As the triggering of<br />
the pellet-induced ELM happens rather independently of the<br />
phase of the natural ELM cycle in which the pellet hits the<br />
plasma, it is improbable that this corresponds exactly to the<br />
instant where the plasma becomes linearly unstable. Rather,<br />
it has to be concluded that the edge plasma must be in a nonlinearly<br />
unstable situation over almost the entire ELMcycle,<br />
and that the finite-amplitude perturbation due to the<br />
pellet suffices to excite further growth.<br />
An interesting observation is that the quiescent H-mode<br />
shows stability against the pellet perturbation, indicating<br />
that in this case some transport enhancement in the pedestal<br />
region (presumably due to the observed edge harmonic<br />
=
oscillations) keeps the profiles in a stable regime. Pellet<br />
injection into ohmic plasmas showed a directly pellet driven<br />
MHD perturbation exceeding by far that one present at the<br />
visible ELM onset thought to be in the order required for<br />
ELM triggering. No correlation was found between the<br />
MHD perturbations with pellet particle ablation or deposition<br />
rate, indicating an already saturated driving mechanism.<br />
Lower local plasma energies result however in a reduction<br />
of the MHD excitation attainable by the pellet perturbation.<br />
The correlation between pellet MHD drive and plasma<br />
parameters are now under investigation.<br />
7.4 Parallel plasma flow and radial E-field in the SOL<br />
The fast reciprocating probe located 30 cm above the torus<br />
midplane was used to investigate the SOL from the limiters<br />
up to the separatrix. It was equipped with swept Langmuir<br />
probes facing in co- and counter-current direction. This<br />
allowed the floating potential (V fl ), the electron density (n e )<br />
and temperature (T e ) and the Mach number (M) of the parallel<br />
plasma flow to be measured all at once. Also the plasma<br />
potential V pl =V fl +3.1T e and the radial electric field E r =-∇ r V pl<br />
could be deduced. In a series of ohmic discharges the density<br />
was varied covering a Greenwald density fraction of<br />
f GW =0.21-0.49 with I p =1 MA and B t =-2 T. The outer divertor<br />
was fully attached at f GW =0.21 and fully detached at<br />
f GW =0.49. On both sides of the probe head the same T e was<br />
found, but compared to values from Thomson scattering<br />
(TS) T e was considerably lower for ΔR=R-R sep 1 cm). When the outer<br />
divertor was (partially) detached M≤0.6 was found at the<br />
separatrix decreasing to M≈0.2 at ΔR≈0.5 cm and rising<br />
again further outward (M≤0.4). Close to the separatrix the<br />
Pfirsch-Schüter and “return flow” can cause the observed<br />
flows but for ΔR>0.5 cm there has to be another contribution<br />
like e.g. a transport related flow. Flow and divertor<br />
detachment are possibly related.<br />
7.5 Impurity flux in SOL<br />
Ion fluxes in the SOL were measured by exposure of collector<br />
probes with the midplane manipulator system and subsequent<br />
quantification of deposited deuterium and impurity<br />
elements by ex-situ ion beam analysis. Discharge-resolved<br />
and even time-resolved measurements within one discharge<br />
can be carried out employing rotating cylindrical samples<br />
inside a shield with a 6 mm wide slit aperture extending<br />
88 mm in a radial direction. Increased impurity fluxes are<br />
observed during the low density current ramp-up phase as well<br />
as in plasma configurations with a small separatrix-sample<br />
distance and increased ion cyclotron resonance heating<br />
ASDEX Upgrade<br />
18<br />
(ICRH) power. The increase of the impurity flux in the first<br />
two cases is attributed to an increased wall flux and correspondingly<br />
higher sputtering flux. In the latter case the interaction<br />
of the ICRH antenna with the plasma is expected to<br />
create a local impurity source increasing with heating power.<br />
In recent experimental campaigns, apart from the dominant<br />
first wall element tungsten, the main impurities were calcium<br />
(from ceramic isolation) and steel constituents (Fe, Ni) from<br />
the vacuum vessel. The derived concentrations of c Fe ≈10 -3<br />
and c W ≈10 -5 at the plasma edge are in good agreement with<br />
spectroscopic measurements. In order to quantify the edge<br />
carbon flux with a full tungsten wall configuration a full<br />
metallic probe head (TZM shield, Al cylinder) has been constructed.<br />
A typical residual carbon deposition rate of a few<br />
10 21 m -2 / discharge was detected and no significant temporal<br />
evolution of the carbon flux throughout the <strong>2007</strong> campaign<br />
could be observed similar to spectroscopic investigations<br />
(see Chapter 2).<br />
7.6 Analysis of divertor profiles<br />
Dedicated discharges with strike point sweeps allowed power<br />
load profiles derived from Langmuir probes to be compared,<br />
assuming P LP =(7 k B T e +E rec )Γ i, and IR thermography.<br />
Figure 20 shows profiles of electron temperature, density<br />
and power fluxes along the outer target for the inter-ELM<br />
phase of a medium and a high density H-mode discharge.<br />
Coherent averaging over about 100 ELM cylces was used to<br />
reduce the statistical uncertainties. While the T e profiles<br />
along the target are flat, the density profiles are peaked close<br />
to the separatrix. For the high density H-mode the profiles<br />
indicate partial detachment around the strike point. The target<br />
profiles (T e , n e , j sat , P IR ) are very similar comparing discharges<br />
with carbon (divertor IIb) and tungsten (divertor<br />
IIc) target plates. The electron power width obtained from<br />
the Langmuir probes using a sheath transmission factor of 8 is<br />
a factor 2 shorter than the one obtained from thermography.<br />
Both widths increase with density, compatible to the trend<br />
seen for the electron temperature decay length as obtained<br />
from Thomson scattering measurements. One exponential<br />
decay length is sufficient to fit the power decay for these<br />
medium/high density conditions. While the power widths<br />
obtained from the probes are a factor 2-3 larger than the<br />
expectation 2/7·λ Te midplane , the thermographic widths are<br />
clearly out of range, suggesting dominant effects of fast ion<br />
impact and/or radiation.<br />
During ELMs, similar power loads are observed at the outer<br />
target from Langmuir probe and thermography analysis for<br />
both divertors IIb and IIc. The large deposited ELM energies<br />
observed with thermography at the inner target have<br />
shifted upward, away from the strike zone from divertor<br />
IIb to IIc. A corresponding redistribution of the target currents<br />
indicates that in fact the impact region of fast ions<br />
has shifted upward.
T e [eV]<br />
2<br />
par. heatflux [W/m ]<br />
30<br />
20<br />
10<br />
21333<br />
21301<br />
-3<br />
n e [m ]<br />
1•10<br />
20<br />
8•10<br />
19<br />
6•10<br />
19<br />
4•10<br />
19<br />
2•10<br />
19<br />
0<br />
0<br />
-0.05 0.00 0.05 0.10 0.15<br />
-0.05 0.00 0.05 0.10 0.15<br />
ds sep (div) [m]<br />
ds sep (div) [m]<br />
10 8<br />
|| power fluxes, mapping to omp<br />
IR<br />
λ= 7.2 mm<br />
10<br />
-5 0 5 10<br />
dR (omp) [mm]<br />
6<br />
10 7<br />
LP<br />
λ= 3.3 mm<br />
10<br />
dR (omp) [mm]<br />
6<br />
10 7<br />
LP<br />
λ= 7 mm<br />
-5 0 5 10<br />
sep<br />
sep<br />
Figure 20: Top: Electron temperature and density profiles along the outer<br />
target for a high density and a medium density H-mode discharge. Bottom:<br />
Parallel heatflux at the outer target mapped to the outer midplane (omp)<br />
from IR thermography (dashed line) and Langmuir probes (solid line) for<br />
the medium density (left) and the high density (right) discharge. The<br />
straight dashed lines indicate the decay length fits. Spatial co-ordinate<br />
dR is the distance to the separatrix in the omp at the vertical position of<br />
sep<br />
the magnetic axis.<br />
7.7 ELM divertor heat loads<br />
A detailed experimental analysis of the temporal evolution<br />
of the power deposition on the inner/outer target plates with<br />
both field directions was performed, focusing on the deposition<br />
time scales of ELMs. It was fitted with an analytical<br />
formula, which describes the arrival of energy at the divertor<br />
target plates due to a <strong>Max</strong>wellian distribution of collisionless<br />
particles. The ELM power deposition on the divertor<br />
target plates can be well described with this simple expression.<br />
Although the asymmetry of the deposited energy as<br />
well as the maximum power deposition values P in and P out<br />
strictly change with the field direction, the temporal evolution<br />
does not show any significant differences between<br />
cases with normal and reversed field. The ELM instability<br />
time τ ELM , is found to be
the peak ion flux by more than one order of magnitude. At<br />
high density the outer target peak ion flux is by a factor of<br />
2 to 3 larger than experimentally observed while for low<br />
density the agreement is satisfying with respect to the peak<br />
fluxes. Stimulated by measurements from a recently installed<br />
pressure gauge in the outer divertor tile, the model<br />
of the neutral conductance below the divertor target plates<br />
and dome has been changed. This led to an increased asymmetry<br />
of the ion flux in the simulations, closer to the experimental<br />
observations.<br />
7.9 Gas balance measurements<br />
Tritium retention due to co-deposition with carbon is a safety<br />
issue for ITER. As ASDEX Upgrade is now operating with a<br />
tungsten first wall, long term fuel retention should be significantly<br />
reduced. As a first step, gas balance measurements<br />
with a carbon dominated first wall have been evaluated to<br />
get a reference value. To reach ITER relevant divertor conditions,<br />
a high gas flow rate (3⋅10 22 at D/s) is used in the discharges<br />
under consideration. Here, 10-20 % of the gas input<br />
is retained during the discharge. Most of this inventory is<br />
released by outgassing in between discharges or during glow<br />
discharge cleaning. This value agrees within the measurement<br />
error with the amount of D found in deposition layers<br />
by post mortem analysis. To extrapolate towards longer discharge<br />
durations, the temporal evolution of the gas balance<br />
during a discharge has to be investigated. During the plasma<br />
build up ≈75 % of the puffed gas is retained, whereas for<br />
high density flat top phases wall saturation is reached with<br />
2⋅10 22 retained D-atoms. After the wall is saturated, all<br />
puffed gas is pumped away within the error bar.<br />
Phase N puffed N pumped N plasma Balance<br />
Limiter 15.0 0.9 3.7 30 %<br />
Ramp-up 47.0 5.1 6.9 20 %<br />
Low density 460 290 8.9 65 %<br />
Saturation 610 590 7.6 96 %<br />
Shot 1150 984 86 %<br />
Table 1: Number of puffed (Npuffed ) and pumped (Npumped ) particles, as well as<br />
particles contained in the plasma (N ) for consecutive discharge phases<br />
plasma<br />
of #20447. The balance denotes the fraction of (Npumped +Nplasma )/ Npuffed .<br />
Table 1 summarizes the results for a typical standard H-mode<br />
discharge (#20447). N gives the number of particles (in 10 20<br />
atoms), which are puffed, pumped and which are in the plasma<br />
during the specific discharge phase. The balance denotes<br />
the fraction of (N pumped +N plasma )/ N puffed .<br />
ASDEX Upgrade<br />
20<br />
7.10 Disruptions mitigation with a new fast valve<br />
A new valve for disruptions mitigation was commissioned<br />
in the <strong>2007</strong> campaign. It is designed as an in-vessel valve<br />
and satisfies very demanding functional requirements. It has<br />
a short opening time (of the order of 1 ms), a large orifice<br />
(14 mm of diameter) and negligible leakage (
The results from the two devices show similarities which<br />
support the concept of dimensional similarity. Of special<br />
interest are the plasma dynamics in the vicinity of the separatrix<br />
where an abrupt change of the phase velocity direction<br />
is observed. It switches from the electron-diamagnetic drift<br />
direction in the core to the ion-diamagnetic drift direction in<br />
the SOL. The direction of propagation is consistent with the<br />
E×B-drift direction deduced from floating-potential measurements<br />
(see figure 22). Across the entire radial sweep a<br />
potential-density cross phase close to zero was measured,<br />
which is consistent with drift-wave turbulence.<br />
v θ (km/s)<br />
10<br />
5<br />
0<br />
-5<br />
A<br />
magnetic field<br />
A<br />
A<br />
radial electric<br />
fields<br />
vExB A<br />
A<br />
DSOL LSOL<br />
-10<br />
0 10 20 30 40 50<br />
distance to nominal separatrix (mm)<br />
Figure 22: Measured poloidal phase velocities show a reversal as consistent<br />
with the E×B drift<br />
8.2 Doppler reflectometry simulations<br />
In collaboration with the AUG team, the experimental<br />
Doppler reflectometry investigations on AUG have been<br />
accompanied by fullwave simulations at IPF. The code<br />
“IPF-FD3D” is a finite difference time domain code that<br />
solves <strong>Max</strong>well’s equations and the electron equations of<br />
motion in cold plasma. The two-dimensional version of the<br />
code is used to investigate the scattering efficiency of the<br />
Doppler reflectometer at different angles of incidence in the<br />
presence of plasma density fluctuations. In <strong>2007</strong>, the incorporation<br />
of measured discharge parameters and profiles into<br />
the code was accomplished and the main work of simulating<br />
actual measurements taken by the reflectometer was started.<br />
In addition, investigation of the scattering efficiency has<br />
been done in slab geometry with linear density profiles, and<br />
simulations with AUG profiles have been started. For slab<br />
geometry in O-mode, it was found that the scattering efficiency<br />
decreases with increasing angle θ between incident<br />
beam and density gradient. At density fluctuation levels<br />
above 2 %, it was found that the returned power at small θ<br />
was also significantly reduced, due to the appearance of<br />
higher scattering orders. In an effort to concentrate the<br />
European reflectometry code development, the European<br />
Reflectometer Code Consortium (ERCC) was founded<br />
under the aegis of <strong>IPP</strong>. It comprises members from Germany,<br />
France, Spain, and Portugal. In 2008, this work will be continued,<br />
and the coupling of reflectometry simulation and<br />
plasma turbulence simulation will be started.<br />
A<br />
ASDEX Upgrade<br />
21<br />
9 International & European Cooperations<br />
ASDEX Upgrade (AUG) cooperations are organised under<br />
IEA Implementing Agreements (IA), the International<br />
Tokamak Physics Activity (ITPA), bilateral contracts and by<br />
providing support and an open structure at <strong>IPP</strong> in particular<br />
for the participation of EURATOM Associations in the AUG<br />
scientific programme. In order to give our guests an even<br />
better opportunity to conduct their scientific programme at<br />
AUG, the weekly operation hours of the device have to be<br />
extended. This idea comes from the Commission Services<br />
and the EFDA leadership. <strong>IPP</strong> has explored the possibility of<br />
increasing the amount of operational time (6 days of AUG<br />
operation instead of 5 per fortnight or increase the number<br />
of extended shifts which have a 30 % higher pulse rate in<br />
comparison with standard shifts). The implementation of<br />
such a step will require an increase in the number of staff by<br />
10 (8.5 engineers/technician, 1.5 physicist), which will only<br />
be possible with substantial external support from the<br />
Associations/EFDA.<br />
9.1 IEA Implementing Agreement<br />
The current role of the Implementing Agreements (IA) as a<br />
vehicle to enable joint experiments proposed by ITPA is<br />
considered to be very important. AUG contributions to such<br />
joint experiments continued in <strong>2007</strong>, but their number decreased<br />
due to the concentration of the <strong>2007</strong> AUG programme<br />
on tungsten related topics. For 2008 however, more than 40<br />
contributions to joint experiments are again foreseen.<br />
In <strong>2007</strong> international discussions on the future of IAs were<br />
started in particular with respect to their interaction with<br />
ITER, but no definite conclusion was reached. The IAs<br />
served as the framework for 13 personnel exchanges between<br />
<strong>IPP</strong> and labs from the US as well as from Korea. A<br />
summary of the collaboration with GA on plasma edge<br />
physics is given in the following.<br />
The effect of the divertor closure on the core plasma poloidal<br />
fuelling profile was investigated by executing ohmic plasmas<br />
similar in configuration and operating space in the AUG<br />
(closed divertor) and DIII-D (open divertor) tokamaks, and<br />
by scrape-off layer modelling using the SOLPS and<br />
UEDGE codes.<br />
At the lowest density, weak dependence of the divertor plasmas<br />
on the divertor closure was observed experimentally. In<br />
both devices the outer divertor plasma is attached to the target<br />
plate, while the inner divertor plasma is partially detached<br />
at the strike point. SOLPS and UEDGE simulations<br />
were validated against the experimental data and predict significantly<br />
more neutral leakage from the inner divertor plasma<br />
for DIII-D, leading to a broader neutral fuelling profile<br />
above the high-field X-point. For both devices the UEDGE<br />
simulations indicate strong poloidal asymmetry of the ion
flux across the separatrix due to classical ion B×B drifts:<br />
strong influx at the top of the plasma, and outflux above the<br />
X-point. The comparison of the experimental and simulation<br />
data was facilitated via common, MDSplus-based databases<br />
generated under the auspices of the ITPA Divertor and SOL<br />
working group.<br />
9.2 EURATOM Associations<br />
The participation of scientists from EURATOM Associations<br />
continued to stay at a high level as in previous years.<br />
In response to the call for participation in the 2008 AUG<br />
campaign more than 160 experimental proposals have been<br />
submitted by 75 scientists. More than 50 % of them are<br />
non-<strong>IPP</strong> scientists. Besides several proposals from DIII-D,<br />
the majority of external proposals originate from scientists<br />
of 14 different EU Associations. In total the execution of<br />
more than 1400 discharges has been requested. The international<br />
AUG Programme Committee met in December and<br />
approved a prioritized programme of roughly 800 shots.<br />
Besides <strong>IPP</strong> ten Associations are represented in this body.<br />
Andrew Kirk a scientist from MAST will take over the<br />
management of the AUG Task Force III “SOL & Divertor<br />
physics and first wall materials”. In the following the most<br />
important contributions from Associations made in <strong>2007</strong><br />
are summarized.<br />
DCU – University College Cork:<br />
Progress made during <strong>2007</strong> in the context of the ongoing<br />
collaboration between <strong>IPP</strong> and University College Cork is<br />
summarized as follows: A significant effort was expended<br />
on CLISTE reconstructions as part of the recalibration of<br />
the MSE diagnostic in light of systematic corrections to<br />
radial channel locations discovered in early <strong>2007</strong>. These<br />
involved analysis of discharges with maximal diagnostic<br />
information on rational surface locations to validate q profiles<br />
obtained with MSE.<br />
CLISTE has been extended to improve the modelling of disrupting<br />
plasmas and now can generate interpretive equilibria<br />
(including halo currents) for plasmas as small as 20 cm in<br />
radius resting on divertor structures. The predictive Garching<br />
Equilibrium Code can now generate ITER equilibria in AUG<br />
shotfile format and construction of a database is underway.<br />
The study of TAE character and stability has been completed<br />
from discharges performed during the 2006 experimental<br />
campaign for cases with ICRH only and combined ICRH<br />
and NBI. Using MSE data, the quality of current profile<br />
reconstructions using TAE mode positions from ICRH-only<br />
discharges and ICRH with beatwaves has been confirmed.<br />
These results will be used to describe in detail the nature and<br />
uses of TAE in ASDEX Upgrade. TAE were also observed<br />
in discharges from the first period of the <strong>2007</strong> campaign, the<br />
first using a full tungsten machine. TAE activity from these<br />
discharges differs significantly from the previous campaign<br />
and analysis of the data is in progress.<br />
ASDEX Upgrade<br />
22<br />
ENEA – Consorzio RFX, Padova:<br />
The ORBIT code has been used to study the fast ion<br />
dynamics in AUG and thus to contribute to the analysis of<br />
the fast ion loss diagnostic measurements (FILD). Several<br />
improvements and corrections have been implemented in<br />
the code in order to perform more realistic simulations to<br />
be compared with experimental data. In particular, the use<br />
of equilibria in straight field lines has been assessed; this has<br />
allowed fast ion physics to be studied in the real D-shaped<br />
geometry of the device instead of a circular approximation<br />
with Boozer co-ordinates. The equilibrium quantities are<br />
computed by the VMEC code and adapted to be accessible<br />
by ORBIT. The main application of the code has been a<br />
study of the fast ion losses induced by Neoclassical Tearing<br />
Modes. The influence of the toroidal magnetic field ripple<br />
has been studied as well. As a further improvement electric<br />
field effects have been implemented to deal with rotating<br />
NTMs. An algorithm to obtain stationary conditions has<br />
been introduced by replacing the lost deuterons with new<br />
ones belonging to the same space and velocity distribution,<br />
which characterizes the ions injected by the NBI system.<br />
Simulations with rotating modes have confirmed most of<br />
the results performed with a stationary mode. It has been<br />
observed that at higher mode rotation frequencies larger<br />
losses occur. This partly agrees with the experimental data,<br />
but further analysis is still needed. In addition, investigations<br />
of the internal structure of TAE modes are reported in<br />
section 6.4.<br />
HAS – KFKI Budapest:<br />
The triggering mechanism of type-III ELMs was investigated<br />
in detail by linking the dynamics of pellet-triggered<br />
ELMs to the pellet trajectory. In order to study the pelletinduced<br />
perturbation which triggers the ELM, magnetic<br />
pick-up coil signals were analysed in ohmic discharges.<br />
Methane doped deuterium pellet experiments were carried<br />
out to study the effect of doping on penetration and pellet<br />
cloud properties. Pellets with methane content between 0.44<br />
and 2.4 % were used.<br />
The effect of pellet injection on target plasma radiation was<br />
investigated by the multi-chord SXR and bolometer systems.<br />
An increase of the total radiation during pellet injection was<br />
observed showing radiation coming from the HFS where the<br />
pellet is ablated. SXR investigations revealed a poloidally<br />
symmetric decrease of the plasma emissivity propagating<br />
inwards during pellet ablation (see section 6.7). Temperature<br />
measurements indicate that the emissivity drop is caused by<br />
the cooling of the plasma.<br />
Further testing was done with a new Lithium ion source<br />
with a surface twice that of the usual one. Although up to<br />
6 mA ion current could be reached the long term reliability<br />
of the source is still not sufficient. The possibility of density<br />
fluctuation measurement using the AUG lithium beam diagnostic<br />
was studied with a single channel observation system.
Although the photon statistical fluctuation level was around<br />
10 %, density fluctuations down to 2 % could be well extracted<br />
using correlation techniques. Installation of a fourchannel<br />
fast detection system is foreseen in 2008.<br />
IST – Centro de Fusão Nuclear:<br />
The swept FMCW profile reflectometer system was not<br />
operated during the <strong>2007</strong> campaign due to waveguide renovation<br />
and installation of ECRH protection shutters. Design<br />
studies for alternate bistatic transmission lines are in progress.<br />
Software development has continued with new algorithms<br />
for the automatic analysis of edge pedestal characteristics,<br />
plus investigations of magnetic ripple effects on<br />
X-mode data inversion to improve the density profile<br />
reconstruction accuracy at the plasma edge and SOL.<br />
Validation studies of the real-time reconstruction procedure<br />
for plasma position monitoring using neural networks were<br />
completed. Using a highly optimized code on a dual core<br />
2 GHz Intel CPU the separatrix position in ELMy H-mode<br />
discharges could be tracked with a
Tokamak Edge and Divertor Physics (E2): K. Behringer,<br />
R. Dux, T. Eich, J. Fink, R. Fischer, J. Gafert, M. Gemisic<br />
Adamov, G. Haas, J. Harhausen, N. Hicks, L. Horton,<br />
A. Kallenbach, B. Kurzan, B. Langer, C. Maggi, P. de Marné,<br />
H. Meister, H. W. Müller, H. D. Murmann, R. Neu, J. Neuhauser,<br />
T. Pütterich, R. Pugno, B. Reiter, V. Rohde, W. Sandmann,<br />
A. Scarabosio, A. Schmid, J. Schirmer, M. Sertoli, K.-H. Steuer,<br />
W. Suttrop, E. Wolfrum, M. Wischmeier, D. Yadikin.<br />
Tokamak Physics Division: C. Angioni, A. Bergmann,<br />
R. Bilato, A. Bottino, M. Brüdgam, A. Chankin, D. P. Coster,<br />
T. Görler, S. Gori, S. Günter, T. Hauff, M. Hölzl, F. Jenko,<br />
O. Kardaun, H.-J. Klingshirn, C. Konz, K. Lackner, P. Lauber,<br />
P. Martin, P. Merkel, F. Merz, G. Pautasso, G. Pereverzev,<br />
E. Poli, M.J. Püschel, T. Ribeiro, W. Schneider, E. Schwarz,<br />
B. Scott, M. Sempf, M. Siccinio, E. Strumberger, C. Tichmann,<br />
C. Wigger, Q. Yu.<br />
Technology Division: S. Assas, W. Becker, V. Bobkov,<br />
F. Braun, R. D’Inca, H. Faugel, P. Franzen, M. Fröschle,<br />
B. Heinemann, D. Holtum, C. Hopf, M. Kick, L. Liu, C. Martens,<br />
J.-M. Noterdaeme, S. Obermayer, A. Onyshchenko, R. Riedl,<br />
J. Schäffler, E. Speth, A. Stäbler, P. Turba, E. Würsching.<br />
Garching Computer Centre: C. Hanke, P. Heimann,<br />
J. Maier, H. Reuter, M. Zilker.<br />
Central Technical Services: F. Ascher, R. Blokker, H. Eixenberger,<br />
T. Franke, I. Goldstein, E. Grois, M. Huart, C. Jacob,<br />
R. Jung, C.-P. Käsemann, M. Kircher, K. Klaster, M. Kluger,<br />
J. Lex, G. Lexa, J. Maier, H. Nguyen, G. Raitmeir, F. Stobbe,<br />
F. Zeus.<br />
Materials Research: M. Balden, H. Bolt, H. Greuner,<br />
W. Jacob, K. Krieger, S. Lindig, H. Maier, M. Mayer,<br />
J. Roth, K. Schmid, W. Schustereder, K. Sugiyama.<br />
<strong>IPP</strong> Greifswald: M. Laux.<br />
IPF University of Stuttgart: E. Holzhauer, W. Kasparek,<br />
H. Kumric, C. Lechte, P. Manz, B. Nold, B. Plaum, M. Ramisch,<br />
U. Stroth.<br />
Humboldt University, Berlin: C. Biedermann, W. Bohmeyer,<br />
R. Radtke, R. Seidel.<br />
FZ Jülich: A. Kreter, A. Litnovsky, O. Neubauer, B. Unterberg,<br />
R. Wolf.<br />
ÖAW, University of Innsbruck, Austria: P. Balan, C. Ionita,<br />
C. Lupo, F. Mehlmann, R. Schrittwieser.<br />
ERM/KMS, Brussels, Belgium: A. Lyssoivan.<br />
<strong>IPP</strong>, Praha, Czech: J. Adamek, V. Weinzettl.<br />
RISØ, Roskilde, Denmark: H. Bindslev, F. Meo.<br />
TEKES, HUT, Espoo, Finland: V. Hynönen, T. Kurki-<br />
Suonio, M. Mantsinen.<br />
TEKES, VTT, Espoo, Finland: J. Likonen, E. Vainonen-<br />
Ahlgren.<br />
CEA, Cadarache, France: T. Loarer.<br />
EFDA Close Support Unit, Garching: A. Loarte.<br />
HAS, KFKI, Budapest, Hungary: G. Anda, S. Bató,<br />
E. Belonohy, K. Gál, S. Kálvin, G. Kocsis, T. Szepesi,<br />
S. Zoletnik.<br />
ASDEX Upgrade<br />
24<br />
DCU, University College Cork, Ireland: P. McCarthy,<br />
K. Sassenberg.<br />
ENEA, IFP, CNR, Milano, Italy: S. Cirant.<br />
ENEA, Consorzio RFX, Padua, Italy: E. Gaio, M. Gobbin,<br />
L. Marelli, P. Martin, P. Piovesan, V. Toigo.<br />
Riga University, Riga, Latvia: O. Dumbrajs.<br />
IST Lisbon, Portugal: L. Cupido, L. Fattorini, S. da Graça,<br />
M.-E. Manso, J. Santos, F. Serra, A. Silva, P. Varela.<br />
NILPRP, Bucharest, Romania: C.V. Atanasiu, G. Miron.<br />
CIEMAT, Madrid, Spain: F. Tabares.<br />
VR, Stockholm, Sweden: P. Brunsell.<br />
CRPP, Lausanne, Switzerland: T. Dannert.<br />
UKAEA Culham, Abingdon, United Kingdom: C. Challis,<br />
D. Howell, A. Kirk, H. Meyer.<br />
University of Strathclyde, Glasgow, United Kingdom:<br />
M. G. O’Mullane, H. P. Summers, A. D. Whiteford.<br />
INEEL, Idaho, USA: P. Sharpe.<br />
University of Wisconsin, Madison, USA: C. Forest.<br />
John Hopkins University, Maryland, USA: M. Finkenthal.<br />
PPPL, Princeton, USA: C. H. Skinner.<br />
UCSD, San Diego, USA: G. Antar.
Introduction<br />
The first three months of <strong>2007</strong><br />
were devoted to experiments extending<br />
the 2006 programme and<br />
to new experiments such as those<br />
with increased toroidal field (TF)<br />
ripple. The latter revealed a rather<br />
strong detrimental effect on plasma<br />
confinement and density, especially<br />
at low ν*. These results<br />
suggest that a TF ripple of less<br />
than 0.5 % is required in ITER to achieve Q DT =10. For the rest<br />
of <strong>2007</strong>, JET activities were focussed on installation of the<br />
ITER-like antenna as well as the new high frequency pellet<br />
injector. Parallel to these shutdown activities the 2008 Workprogramme<br />
(~170 S/T days) was prepared, whereby a modified<br />
procedure was used. Instead of asking EU Associations<br />
for written proposals, the programme was established by the<br />
JET Task Forces (TF). Since autumn <strong>2007</strong> the JET scientific<br />
management has been supported by P. Lang and Th. Eich,<br />
working as deputy TF leaders for TF S1 and E, respectively.<br />
Contributions to campaigns C18-C19<br />
A major outcome of the hybrid scenario experiments at JET was<br />
the fact that in such discharges the performance (mainly in<br />
confinement, but also in β stability) is very similar to standard<br />
H-mode discharges without q-profile modification. The latter<br />
has been produced by means of LHCD in the preheat phase to<br />
prepare a target q-profile which should be maintained by an<br />
increased bootstrap current fraction (f BS ). In <strong>2007</strong> the analysis<br />
concentrated on the q-profile and its time dependence. It has<br />
been shown that in pulses with very similar performance the<br />
q-profile is also almost identical. A systematic study of the<br />
q-profiles in the hybrid pulses has proven that formation of the<br />
q-profile is not efficient. Immediately after starting NBI heating<br />
(0.5 s) the q-profile has a q=1 surface and is very similar to a<br />
non-modified, standard q-profile. Also in the later phase of the<br />
pulse the maximum f BS determined by TRANSP does not exceed<br />
30 %. This is not sufficient to maintain the initial modification.<br />
One reason for such a low f BS at high β N is the large fast particle<br />
fraction caused by the long slowing down time of NBI ions.<br />
The JET part of the ITPA joint experiment MDC-3, involving<br />
also AUG and DIII-D, for the (2/1)-NTM marginal β pol scaling<br />
was continued. Besides <strong>IPP</strong>, FZ-J, FOM and UKAEA have<br />
been involved in the preparation, execution and in the data<br />
analysis of the <strong>2007</strong> JET experiments on (2/1) NTM scaling.<br />
Together with the database from 2004/6 an independent scaling<br />
of the marginal β pol for the (2/1)-NTM is now possible.<br />
Ion heat transport is predicted to be driven by ITG turbulence<br />
and should exhibit a threshold and a certain stiffness of radial<br />
profiles. Experiments were carried out to investigate the exis-<br />
JET Cooperation<br />
Head: Dr. Josef Schweinzer<br />
JET started <strong>2007</strong> with three months of operation<br />
with the main aims to extend the 2006 programme<br />
and to conduct a TF ripple experiment.<br />
For the rest of the year JET operation was interrupted<br />
to install the ITER-like ICRH antenna.<br />
Parallel to the shutdown, the JET EP2 project<br />
proceeded well and the preparation of the 2008<br />
campaigns with more than 170 S/T days has<br />
been finished. In many of these activities <strong>IPP</strong><br />
has been substantially involved.<br />
25<br />
tence of the expected ITG threshold<br />
and the actual stiffness of<br />
ion heat transport in steady-state<br />
scans of the power deposition<br />
profile. Transport simulations<br />
were performed to prepare the<br />
experiment and to assess the experimental<br />
requirements and possibilities.<br />
Ion temperature modulation<br />
experiments done in 2006<br />
have been analysed with validated<br />
diagnostic data. The results<br />
point to a stiffness factor of ion heat transport in the range of<br />
theoretical predictions. A set of experiments on fast ion redistribution<br />
was carried out, using the new fast ion loss scintillator<br />
probe KA3. Fast ion losses were measured and effectively attributed<br />
to MHD activity, such as sawtooth crashes, TAE and high<br />
frequency fishbones. A few sawtooth events have been analysed<br />
in detail to clarify which particles lead to stabilization and thus<br />
cause a destabilizing effect when they are expelled from the<br />
plasma by other processes. Every sawtooth event at sufficiently<br />
low enough plasma density is accompanied by a clearly observed<br />
spike in the detected particle loss signal, which is more<br />
than a factor of three larger than signals from prompt losses of<br />
ICRH induced fast protons. Regarding the risks of first wall<br />
damage in future tokamaks, these experiments have shown that<br />
fast ions are lost at very high energies, of the order of a few MeV,<br />
and that the losses increase significantly with ICRH power.<br />
Due to the limited power-handling capabilities of the future<br />
ITER-like wall (ILW) an effort aimed at mitigating the target<br />
plate power loading associated with AT plasmas was initiated.<br />
The necessity for such a program was further underlined by the<br />
upgraded heating potential foreseen within EP2 enhancements.<br />
To this end a configuration was first established with<br />
good diagnostic coverage of the edge/divertor plasma, followed<br />
by impurity-seeding experiments with Ne and N 2 . It was<br />
established that good ELM control could be achieved with<br />
neon seeding, while maintaining core plasmas compatible<br />
with AT scenarios. The achieved power unloading at the outer<br />
strike point is judged adequate for the ILW-phase but not sufficient<br />
for the inner divertor. Further configurational/impurityseeding<br />
studies will be pursued in 2008 based upon these results.<br />
Otherwise, excellent edge/divertor datasets were obtained.<br />
These provide the basis for ongoing edge modelling studies.<br />
Spatial and temperature calibration of the Kl3b divertor<br />
periscope infra-red camera was performed including a sophisticated<br />
setup of transformation matrices. Furthermore,<br />
new limits of hardware data acquisition have been exploited.<br />
Full toroidal/poloidal resolution IR divertor profiles have<br />
been produced on a 200 us time scale, which is an improvement<br />
of about a factor 5-10. Software optimization for strike<br />
line splitting in ELM mitigation experiments with an edge<br />
ergodised by external field perturbation was accomplished.
From bolometer (KB5) studies in 2006 it was known that the<br />
characteristic spectra of carbon lines emitted from the divertor<br />
region falls in a range where the detection efficiency of<br />
gold is less than 100 %. The goal was to expand the findings<br />
for carbon to other gases commonly used for impurity seeding<br />
experiments such as N 2 and Ne since it is important that the<br />
bolometer correctly register the level of radiation. Unfortunately,<br />
no quantitatively measured spectra exist from the<br />
divertor/X-point region for JET, nor for other experiments<br />
elsewhere. Thus, it was decided to generate radiation coefficients<br />
for various impurities as a function of T e under the<br />
assumption of coronal equilibrium and fold these into the<br />
detection efficiency curve of gold as a first approximation.<br />
Plasma edge and divertor modelling<br />
Current edge codes form an important bridge between results<br />
on present machines and divertor operation on ITER. In<br />
order to place the ITER predictions on a firmer footing, an<br />
effort has been started to verify existing codes by careful<br />
code-code comparison, and then to validate the codes against<br />
the experiment. Previous results of the EDGE2D-NIMBUS,<br />
B2-EIRENE (SOLPS5) comparison for the D only case were<br />
already reported. During C18-C19, these results were extended<br />
to D+C for SOLPS, and some results for D & D+C<br />
for EDGE2D-NIMBUS and EDGE2D-EIRENE were also<br />
obtained. One of the major results was a renewed look at the<br />
atomic data used. For one particular case, the peak target<br />
electron temperature was found to change by a factor of<br />
nearly 10 depending on the choice of atomic data.<br />
SOLPS simulations of AUG plasmas have been compared<br />
with EDGE2D modelling of JET discharges, regarding the<br />
value of radial electric field (E r ) in the SOL. Realistic EDGE2D<br />
cases were run simulating a real JET discharge as a starting<br />
point, with subsequent wide variation of separatrix density and<br />
input power. The relative roles of the Debye sheath, parallel<br />
electron temperature and pressure gradient terms, and ionelectron<br />
friction in the formation of the upstream (at outer<br />
midplane) E r in the SOL could be identified. The simulations<br />
delivered low E r values which are in contradiction to high E r<br />
values measured on both AUG and JET. A possible reason for<br />
this discrepancy lies in the nature of today’s widely used 2D<br />
codes, which ignore non-local kinetic effects in the parallel<br />
transport of heat-carrying electrons that are only very weakly<br />
collisional in the SOL. Such electrons can raise target T e and<br />
thus directly affect the Debye sheath formation.<br />
Enhancements<br />
<strong>IPP</strong>’s JET-EP diagnostic projects KB5 bolometer and KA3 fast<br />
ion loss scintillator probe have been closed. Both diagnostics<br />
are delivering high quality data. <strong>IPP</strong> supports various JET-EP2<br />
projects with different levels of involvement. The ICRF group<br />
has contributed to the development of a sub-harmonic arc<br />
JET Cooperation<br />
26<br />
detection system for the new ITER-like ICRF antenna, and<br />
has regularly attended the project board meetings.<br />
In support of the ILW project <strong>IPP</strong> leads a diagnostic project<br />
to improve the resolution of the divertor infra red measurement.<br />
The new system will be able to measure the power<br />
deposition on the outboard divertor target during type-I<br />
ELMs and should resolve the ELM filamentary structure. In<br />
<strong>2007</strong>, the TCDI process was finished. The camera was tested<br />
at <strong>IPP</strong> and will be installed at JET in February 2008. To support<br />
commissioning and in particular to effect efficient scientific<br />
exploitation, additional personnel were recruited.<br />
Tungsten (W) is foreseen as a plasma-facing material for the<br />
ILW project. The determination of W erosion at the divertor<br />
strike points is a scientific and technical challenge due to the<br />
high net erosion over the entire campaign and the very rough<br />
surfaces. A test marker coating consisting of an 8 μm molybdenum<br />
interlayer and 6 μm W marker coating on a plasmasprayed<br />
200 μm W layer on carbon-fibre composite (CFC) has<br />
been analysed with ion beam analysis methods using 3.5 MeV<br />
incident protons. The results from ion beam analysis were in<br />
good agreement with metallographic cross-sections.<br />
W layers with initial thicknesses of 0.8 μm and 1.6 μm were deposited<br />
at the load-bearing septum replacement plate LBSRP14<br />
and exposed over 2004-2006. A maximum mean W erosion of<br />
about 150 nm was observed. Despite this relatively small mean<br />
value the erosion pattern was strongly inhomogeneous, with<br />
total erosion of the initial W layer on the plasma exposed sides<br />
of microscopic ridges of the rough CFC surface. Due to this<br />
strongly inhomogeneous erosion the thicknesses of protective<br />
coating must be considerably thicker than the mean erosion.<br />
In continuation of <strong>IPP</strong>’s involvement in the ILW project, a new<br />
EFDA task was launched with the purpose to support the<br />
optimisation of the selected coating deposition processes in<br />
preparation for the series production of all CFC W coatings.<br />
This entailed high heat flux testing of W coatings on CFC in<br />
cooperation with the selected contractors in <strong>IPP</strong>’s high heat<br />
flux facility GLADIS and was supplemented by metallographic<br />
and electron-microscopic investigations. With Plansee SE<br />
the applicability of vacuum plasma-sprayed W coatings on<br />
full-size divertor tiles and a possible alternative were investigated.<br />
The Romanian Association MEdC was supported in<br />
their effort to set up a series production facility. The task<br />
will be continued in 2008 by providing expertise and quality<br />
assurance tests during the production phase.<br />
Scientific Staff<br />
A. Chankin, D. P. Coster, R. Drube, Th. Eich, C. Fuchs, J. Gafert,<br />
M. Garcia Munoz, H. Greuner, J. Hobirk, Ch. Hopf, L. D. Horton,<br />
Ch. Konz, K. Krieger, P. T. Lang, H. Maier, G. Matern, M. Mayer,<br />
M. Maraschek, K. McCormick, R. Neu, J-M. Noterdaeme,<br />
R. Pugno, M. Reich, F. Ryter, J. Schweinzer, A. C. C. Sips,<br />
J. Svensson, A. Stäbler, G. Tardini, W. Treutterer, W. Zeidner.
Stellarator Research
1 Introduction<br />
In <strong>2007</strong> the organisation of the<br />
project Wendelstein 7-X has<br />
further developed. In order to fit<br />
the organisational structure to<br />
the evolving requirements and<br />
especially to improve the efficiency<br />
of change management,<br />
a new sub-division was set up:<br />
The Design and Configuration<br />
division concentrates all departments<br />
dealing with design and with control of the configuration<br />
and its changes. The Quality Management department<br />
now reports directly to the associate director for coordination<br />
to clearly emphasize its importance for the project.<br />
Design and manufacturing of the different components<br />
of the basic device have considerably progressed, as described<br />
in chapter 2 and 3. This work is still accompanied<br />
by strong efforts of the Engineering subdivision (chapter 4)<br />
and by design work and configuration control (chapter 5).<br />
The assembly of the stellarator device and the development<br />
of the related technologies have progressed well, as<br />
Project<br />
Coordination<br />
H.-S. Bosch<br />
(A. Lorenz)<br />
Project Control<br />
A. Lorenz<br />
Documentation<br />
U. Kamionka<br />
Design and<br />
Configuration<br />
D. Hartmann<br />
(R. Brakel)<br />
Design Office<br />
D. Pilopp<br />
Configuration<br />
Management<br />
R. Brakel<br />
Configuration<br />
Space Control<br />
C. Baylard<br />
Wendelstein 7-X<br />
Heads: Dr. Remmelt Haange, Prof. Thomas Klinger<br />
In <strong>2007</strong>, construction of Wendelstein 7-X made<br />
great progress. The problems with the non-planar<br />
coils were overcome and delivery of all<br />
components progressed very well. In the fall of<br />
<strong>2007</strong>, all coils on the first two half-modules<br />
were threaded onto the plasma vessel half-modules<br />
and were fixed to the half-modules of the<br />
central support ring. Assembly of the support<br />
elements started. Measures were implemented<br />
to guarantee that assembly is finished in 2014.<br />
Quality<br />
Management<br />
J.-H. Feist<br />
Engineering<br />
F. Schauer<br />
(V. Bykov)<br />
Design<br />
Engineering<br />
V. Bykov<br />
Development<br />
and Test<br />
D. Hathiramani<br />
Instrumentation<br />
J.P. Kallmeyer<br />
Assoc. Director<br />
Coordination<br />
H.-S. Bosch<br />
29<br />
described in chapter 6. Diagnostics<br />
developments (chapter 7)<br />
and the set-up of heating systems<br />
(chapter 8) as well as the<br />
development of control systems<br />
have continued.<br />
1.1 Project Coordination/Quality<br />
Management<br />
This subdivision comprises two<br />
departments dealing with coordination<br />
activities for the project<br />
Wendelstein 7-X: (I) Project Control is responsible<br />
for the financial planning of the project and for the control<br />
of the expenditures, time planning of all the activities<br />
in the project as well as of the external contracts. It supports<br />
the component responsible officers in handling their industry<br />
contracts as well as in organisational aspects of<br />
the project and in the reporting to all external supervising<br />
bodies, especially the “Projektrat”, the supervising body of<br />
the financing institutions. The department was concerned<br />
with the development of a new planning tool, based on MS<br />
PROJECT <strong>2007</strong>.<br />
Project W7-X<br />
T. Klinger R. Haange<br />
Assembly<br />
L. Wegener<br />
(F. Hurd)<br />
On-Site<br />
Co-ordination<br />
S. Gojdka<br />
Device<br />
Assembly<br />
K.H Oelgemöller<br />
Periphery<br />
R. Krampitz<br />
Assembly<br />
Technology<br />
F. Hurd<br />
Figure 1: Organigramme of the Wendelstein 7-X project as of 31 December, <strong>2007</strong><br />
Magnets and<br />
Cryostat<br />
U. Nielsen<br />
(A. Cardella)<br />
Magnet<br />
Manufacturing<br />
K. Riße<br />
Magnet<br />
Testing<br />
J. Baldzuhn<br />
Cryostat<br />
A. Cardella<br />
Supply Systems<br />
and Divertor<br />
M. Wanner<br />
(Th. Rummel)<br />
Power Supplies<br />
Th. Rummel<br />
In-Vessel<br />
Components<br />
R. Stadler<br />
Cryogenics<br />
M. Nagel<br />
Physics<br />
F. Wagner/ R. Wolf<br />
(V. Erckmann)<br />
Diagnostics<br />
R. König<br />
ECRH<br />
V. Erckmann<br />
ICRH<br />
D. Hartmann<br />
NBI<br />
E. Speth<br />
Device Control<br />
J. Schacht<br />
Computing<br />
G. Kühner<br />
Diagnostic<br />
Software<br />
A. Dinklage
It is designed to integrate time and financial planning into<br />
one software solution with interface to SAP. This allows for<br />
automatic reporting to both the management and the supervising<br />
bodies. The concept for this management tool has<br />
been developed jointly with the <strong>IPP</strong> administration and an<br />
external consultant. (II) The documentation department is<br />
responsible for an independent check of all technical drawings<br />
and CAD-models and for archiving all documents relevant<br />
to the project. An electronic documentation system<br />
(agile-PLM) is used for archiving documents and CAD<br />
models (in CADDS5-format). Because of the increased use<br />
of CATIA v5 for design and collision investigations, a prototype<br />
interface has been implemented to allow archiving. A<br />
third department, quality management (QM), reports directly<br />
to the project directors via the associate director coordination.<br />
The department organises the QM system within the<br />
project W7-X and supports all external contractors. It took<br />
over responsibilities for quality assurance during the assembly<br />
phase of Wendelstein 7-X. In addition, the QM system, which<br />
was formerly based on the ISO 9001:1994 standards, has<br />
been updated and adjusted according to the ISO 9010:2000<br />
rules. The difference is that the new rules are more concerned<br />
with processes and not anymore with products,<br />
which is much better suited for the a prototype like W7-X.<br />
1.2 Schedule<br />
With the superconducting coils becoming available, the preassembly<br />
of the first two half-modules resumed in spring<br />
2006. The last coils were threaded onto the plasma vessel in<br />
September and thereafter the central support ring and the<br />
support elements were assembled. Pre-assembly of the first<br />
two magnet half-modules is scheduled to be finished by<br />
March 2008. As outlined in the previous annual report, the<br />
project had proposed to set-up a second assembly line for<br />
the magnet half-modules and the magnet modules in order<br />
to accelerate the assembly process. This proposal has not<br />
been approved due to the uncertain delivery situation of the<br />
components. Instead, the project undertook another thorough<br />
review of the assembly sequences: By introducing<br />
additional shift work and some simplification of the<br />
machine for first plasma operation, the machine assembly<br />
will be completed in 2014 without an increase in the project<br />
budget up to end 2014. Starting from the most recent schedule<br />
for the assembly, various changes in the project planning<br />
were investigated in order to make considerable savings in<br />
time whilst remaining within the budget. The remaining<br />
risks both in the schedule and in the budget were minimised,<br />
too. The schedule can be kept only by a staged approach for<br />
the operation of W7-X (“scenario 3”), i.e., instead of equipping<br />
the experiment for steady-state operation immediately,<br />
three consecutive phases are proposed:<br />
1) In the first operations phase without the full set of “invessel”<br />
components the fundamental stellarator proper-<br />
Wendelstein 7-X<br />
30<br />
ties and optimisation procedures are investigated with<br />
plasma discharges of 5-10 s duration. This phase should<br />
last no longer than 2 years.<br />
2) During a subsequent shut down of approximately 1 year<br />
(“completion phase”) construction of the machine for<br />
steady-state operation is completed.<br />
3) The transition to steady-state operation is made in a second<br />
operations phase with a water-cooled divertor and all<br />
other in-vessel components. In this phase the physics and<br />
technology questions in connection with ITER and<br />
DEMO can be addressed.<br />
The following measures are required to ensure the completion<br />
of the assembly by 2014:<br />
– Reduction in the number of ports (by 15 %)<br />
– Installation of a much simpler, inertially cooled divertor<br />
– Shifting some components that are not necessary for the<br />
first operations phase into the completion phase<br />
– Intensifying shift work<br />
– Increasing parallel assembly steps by procuring additional<br />
assembly equipment<br />
Implementation of scenario 3 has started in the fall of <strong>2007</strong>.<br />
It foresees the end of assembly and start of commissioning<br />
in May 2014. At the end of <strong>2007</strong>, the first two half-modules<br />
have been equipped with seven coils each and these coils<br />
have been fixed to the central support ring. Presently the<br />
inter-coil support elements are assembled.<br />
2 Magnets and Cryostat<br />
2.1 Magnet System<br />
2.1.1 Superconducting Coils<br />
The superconducting coil system of the W7-X consists of<br />
50 non-planar and 20 planar coils. The coils are based on a<br />
special developed cable-in-conduit superconductor that is<br />
composed of an NbTi cable enclosed by an aluminium<br />
jacket. The void within the cable bundle is used for the helium<br />
coolant. The production of the superconductor for the<br />
70 superconducting magnets and the spare lengths has been<br />
completed. The non-planar coils have been contracted to a<br />
consortium formed by Babcock Noell GmbH and ASG<br />
Superconductors S.p.A. 46 non-planar coils have been completed<br />
until end of <strong>2007</strong>. 23 of them are accepted for assembly,<br />
two coils are currently tested and 21 coils are pending<br />
for tests in the facilities at CEA Saclay or Forschungszentrum<br />
Karlsruhe (see below). The last 4 coils will be<br />
delivered until March 2008. The aim of non-planar coil production<br />
was to reach series production with a delivery frequency<br />
of two or three coils per month in the year <strong>2007</strong>.<br />
Another important goal was to finalise the necessary repair<br />
actions on the coil insulation. Both have been achieved.<br />
The application of an additional HV test under so-called<br />
Paschen-minimum conditions (reduced pressures) turned<br />
out to be very useful to investigate the insulation quality.
The manufacture of the 20 planar coils at Tesla Engineering<br />
Ltd. has been finished in November <strong>2007</strong>. 10 coils passed<br />
successfully the acceptance tests under cryogenic conditions.<br />
Wendelstein 7-X<br />
31<br />
2.1.3 Coil Support Structure<br />
The coil support structure is being manufactured by the<br />
Spanish contractor Equipos Nucleares, S.A. (ENSA). It consists<br />
of ten identical sectors with a total weight of 72 t made<br />
from steel plates and cast extensions. The final precision<br />
machining is performed by ENSA subcontractor Rovera<br />
C.M., Italy. The 1 st and 2 nd half-modules of the module 5<br />
have been completed and delivered to <strong>IPP</strong> at the beginning<br />
of <strong>2007</strong>. Both were successfully assembled with the coils<br />
meeting the tight manufacturing tolerances (0.1 mm). The<br />
final machining of the 3 rd and 4 th half-modules (module #1)<br />
has been successfully completed in Rovera in the second<br />
half of <strong>2007</strong>. The components were then delivered to ENSA<br />
for the installation of the cooling tubes and the instrumentation.<br />
The components are planned to arrive in <strong>IPP</strong> at the<br />
beginning 2008. Rovera has already started performing the<br />
final machining of the 5 th and 6 th half-modules and ENSA is<br />
also in parallel completing the main body construction and<br />
extension assembly of the 7 th half-module.<br />
2.1.2 Coil Tests<br />
As in the years before, each superconducting coil for W7-X<br />
is tested in the cryogenic coil test facility of the Commissariat<br />
à l’Énergie Atomique (CEA) in Saclay, France. In<br />
<strong>2007</strong> a total number of tests on 13 non-planar and 5 planar<br />
could be finished successfully. Several improvements of the<br />
test procedure were implemented. Additional Paschen tests<br />
and vacuum leak tests, performed on each individual coil at<br />
<strong>IPP</strong>, complement the CEA tests and complete the acceptance<br />
checks. In the mean time coil testing became routine. Henceforth<br />
no significant quality problems are expected for the<br />
remaining coils. During the whole year <strong>2007</strong>, the test facility<br />
worked without major interruptions or technical malfunctions.<br />
It seems that all systematic manufacturing weaknesses<br />
on the coils are now localised, detected and repaired. Hence,<br />
one can be optimistic that coil tests can be financed right in<br />
time for the assembly of the W7-X coil system. In parallel to<br />
the coil tests at CEA, the TOSKA facility of the Forschungszentrum<br />
Karlsruhe (FZK) is refurbished to test coils in 2008<br />
and 2009. For that purpose, a contract was signed between<br />
FZK and <strong>IPP</strong> to define the mutual tasks during re-activation<br />
of the facility and the test procedure of the coils, and to<br />
commit the contractual payments from <strong>IPP</strong> to FZK. Several<br />
major tasks were already tackled, both by <strong>IPP</strong> and FZK,<br />
to prepare TOSKA for re-operation. For instance, FZK<br />
purchased a new vacuum pump system, maintained and<br />
modified the high current power supply, installed the warm<br />
bus-bars, modified the current-leads, made the design for<br />
the current-lead extensions, procured the cryogenic valve<br />
system and the racks for the electronics, finalised the concept<br />
for an entirely new data acquisition system, the safety<br />
and quench detection control electronics, the feed-forward<br />
control electronics for the operation of TOSKA and the helium Figure 2: Installation of the cooling tubes<br />
liquefier and all cryogenics installations, defined all parameters<br />
and interfaces between machine control, data acquisition,<br />
storage and data base system. <strong>IPP</strong> recruited and<br />
trained the coil test crew, made the design for the cryogenic<br />
high-current joints and manufactured the hardware, built up<br />
the entire cryogenic bus-bar system and all mechanical support<br />
structures inside the TOSKA cryostat, procured and<br />
tested the actively cooled test frames as well as the mechanical<br />
base plate, provided the test electronics for the DC- and<br />
AC-testers as well as the sensor test system, manufactured<br />
the cryogenic cable harnesses, finalised the concept and<br />
design of the coil joints and the removable bus-bar system<br />
directly on the coils, and will provide the hardware for it. It<br />
is envisaged to deliver the first coils to Karlsruhe beginning<br />
of 2008 for testing. Presently a start-up scenario for the<br />
commissioning of the entire test facility is being developed. Figure 3: Front view of module 5.0
Three contracts have been awarded for the R&D and the<br />
manufacturing of the vertical supports of the coil support<br />
structure (“cryolegs”): Zanon s.pa. Italy for the metallic<br />
structure, IMA for the GFC parts, SKF for the sliding and<br />
spherical bearings.<br />
The tests of the sliding and spherical bearings are being<br />
prepared.<br />
2.1.4 Inter-coil Supports<br />
Several support types connect the coils to each other. The<br />
Narrow Support Elements (NSE) between non planar coils<br />
bear pressure loads allowing sliding and tilting. All the<br />
NSE-Pads and -frames of the half-modules 5.0 and 5.1 are<br />
now completed and assembled with the exception of the<br />
NSE elements between the half-modules, which waits for<br />
the completion and assembly of the half-modules into modules.<br />
The Lateral Support Elements (LSE) are welded to the<br />
non planar coils. They rigidly interconnect adjacent coils at<br />
their outer perimeter. The semi products of the LSE for<br />
module 5.0 and 5.1 have been manufactured. The final, custom<br />
machining will be performed after the as-built geometry<br />
between the coils has been measured. The planar support<br />
elements (PSE) connect the planar coils to the non planar<br />
coils. The first PSE (type A1) for HM 5.0 has been success-<br />
Wendelstein 7-X<br />
Figure 4: Test of bearings for cryolegs Figure 5: Detail of the bearing for cryolegs<br />
32<br />
fully completed and installed. The second PSE A1 and the<br />
PSE (type B1) for HM 5.1 are under completion.<br />
Figure 6: PSE A1 installed on the coils<br />
2.2 Vessel and Cryostat<br />
The plasma is surrounded by the plasma vessel, which follows<br />
the plasma contour and constitutes the first ultra-highvacuum<br />
barrier. The entire superconducting coil system is
assembled between the plasma vessel and the outer vessel,<br />
which function as a cryostat keeping the magnet system at<br />
cryogenic temperature and constitute the boundary between<br />
W7-X main device and the external environment.<br />
254 (reduced by 45) ports, manufactured by Romabau<br />
Gerinox, give access to the plasma vessel for diagnostics,<br />
additional heating and supply lines. Deggendorfer Werft und<br />
Eisenbau GmbH (MAN DWE) are responsible for manufacturing<br />
the plasma vessel, the outer vessel and the thermal<br />
insulation.<br />
2.2.1 Plasma Vessel<br />
The plasma vessel consists of ten half-modules, each divided<br />
into two sectors to allow stringing of the innermost<br />
coil during assembly. Construction of the plasma vessel<br />
required 200 steel rings to be bent to the designed shape and<br />
carefully welded to represent the changing cross-section of<br />
the vessel with an accuracy of its final shape 3 to 7 mm.<br />
Vacuum tightness of the welds was checked by an integral<br />
helium leak test of the vessel segments prior to cutting the<br />
holes for the ports. Water pipes around the vessel allow<br />
control of its temperature during plasma operation and for<br />
bake-out at 150 °C. Manufacture of all ten half-modules has<br />
been completed in 2005 and installation of the thermal<br />
insulation has started. The first Rogowski and saddle coils<br />
for magnetic diagnostic have been mounted on the outside<br />
of the first vessel sector during assembly preparation. The<br />
two half-modules (50 and 51) have been integrated with all<br />
coils. The two sectors forming a half-module have been<br />
joined by welding. In both cases the welding was achieved<br />
with very low shrinkage, applying the results of the R&D<br />
performed in 2006 to optimise and qualify the procedure.<br />
The cooling pipe inlet and outlet lines have been manufactured<br />
and assembled. These run between the several components<br />
inside the cryostat and exit from the outer vessel.<br />
Their routing and accurate 3D bending has been more time<br />
consuming than expected but finally arrived in time. The<br />
two main brackets of the plasma vessel are being manufactured.<br />
Their design had to be modified because of collisions<br />
and interface problems with the thermal insulation.<br />
The first two plasma vessel vertical supports have been<br />
completed by MAN DWE. The horizontal support/centring<br />
system design has been completed.<br />
2.2.2 Outer Vessel<br />
The outer vessel consist of five lower and upper half-shells<br />
and will have 524 domes for ports, supply lines, access<br />
ports, instrumentation feed through and magnetic diagnostics.<br />
All upper and lower main bodies of the half-shells of<br />
the outer vessel have been manufactured. Cutting of all<br />
the openings of all the modules has been finished. The details<br />
of the design of the vessel support to the machine bed<br />
have been finalised. The half-modules 5.0, 5.1, 1.0 and 1.1<br />
Wendelstein 7-X<br />
33<br />
have been basically completed in MAN DWE. The first<br />
acceptance tests of half modules 4.0 and 4.1 have being successfully<br />
performed in December <strong>2007</strong>. In parallel MAN<br />
DWE is completing the assembly of the domes of halfmodules<br />
2.1 and 2.0.<br />
Figure 7: Pre-assembled lower and upper shells of module 5<br />
2.2.3 Ports<br />
A total of 254 ports are used to evacuate the plasma vessel,<br />
for plasma diagnostics and heating, as well as for supply<br />
lines and sensor cables. The cross sections of the ports<br />
range between 100 mm circular up to 400×1000 mm 2<br />
square and are equipped with bellows to compensate deformations<br />
and displacements of the plasma vessel with<br />
respect to the outer vessel. The ports are surrounded by<br />
water pipes to control their temperature. All ports and their<br />
fixing tools have been delivered in <strong>2007</strong> and the contract<br />
with Romabau has been successfully concluded.<br />
Figure 8: Port
Figure 9: Fixing tool of the port<br />
3 Supply System and Divertor<br />
3.1 Current Leads<br />
Fourteen current leads are able to carry 18 kA each to connect<br />
the seven groups of superconducting coils to the corresponding<br />
power supplies. Forschungszentrum Karlsruhe<br />
(FZK) is developing, designing, manufacturing and testing<br />
the current leads. The current leads contain high temperature<br />
superconducting (HTC-) material in order to keep the refrigeration<br />
requirements small. A particular feature of the<br />
leads is that they are operated upside down, i.e. with the<br />
cold end on top. Therefore the design of the heat exchanger<br />
has to avoid free convection within the flow channels. Free<br />
convection would short-circuit the heat flow between inlet<br />
and outlet and degrade performance particularly at small<br />
flow velocities. FZK has successfully tested a prototype<br />
heat exchanger in upside-down position and verified that<br />
the envisaged HTC-superconducting tapes have the required<br />
critical current of 34 A at a temperature of 77 K and a<br />
magnetic induction of 150 mT. Electrical insulation of the<br />
current-lead housing from the W7-X cryostat requires the<br />
development of a glass fibre reinforced flange. Tests on a<br />
sample flange have demonstrated its capability to take the<br />
specified forces and moments. The interfaces of the helium<br />
cooling lines with the bus lines, the cold electrical contact<br />
and the heat exchanger were defined and fixed. Instrumentation<br />
will be mostly provided by <strong>IPP</strong> to ensure compatibility<br />
with the cryostat instrumentation. The detailed design<br />
of the current leads was meanwhile completed by FZK. The<br />
mechanical supports of the current leads against the W7-X<br />
cryostat still need to be adapted to keep the loads and<br />
moments during cool-down and magnet operation within<br />
acceptable limits. Design of the test facilities was continued<br />
by FZK. The facilities comprise distribution box, cryogenic<br />
transfer lines and a test box for the current leads.<br />
Wendelstein 7-X<br />
34<br />
<strong>IPP</strong> supports the design and construction with personnel<br />
resources and will provide cold and warm contacts as well<br />
as a unit of the quench detection system (see below) for the<br />
tests of the leads.<br />
3.2 Magnet Power Supply<br />
The five types of non-planar and two types of planar coils<br />
are energised by power supplies providing direct currents of<br />
up to 20 kA at voltages of up to 30 V. Fast and reliable discharge<br />
of the superconducting magnets in case of quenching<br />
is realised by fast circuit switches which short-circuit the<br />
coils and dump the magnetic energy into nickel resistors The<br />
manufacturer ABB has demonstrated that the current can be<br />
stabilised to an accuracy of 2×10 -3 . Following the delivery<br />
of the final documentation and a training of operators,<br />
acceptance of the power supply and magnet protection<br />
system was declared mid <strong>2007</strong>. Since then some practical<br />
experience has been gained with the system. The special<br />
rubber water hoses which isolate the water supply from<br />
high-voltage in case of a rapid shut-down had to be replaced<br />
because their resistivity decreased intolerably with time.<br />
The quench detection system was developed in cooperation<br />
with FZK. The system consists of some 325 quench detection<br />
(QD) units which permanently check the differential<br />
voltages across the double layers of the coils, all sectors of<br />
the bus system and the superconducting part of the current<br />
leads. The system has to reliably detect millivolt signals in a<br />
broadband noise environment and operate at high voltages<br />
during a rapid shutdown of the magnets. The first QD subsystem<br />
consists of 72 quench detection units, a data acquisition<br />
system and an internal battery buffered AC-DC power<br />
converter. It has successfully passed works tests and was<br />
delivered to Greifswald. Safety analyses have shown that<br />
potential grounding faults of a magnet coil should be detectable<br />
during magnet operation. This would reduce the<br />
risk of a high-voltage discharge in case of a rapid shut-down<br />
and simultaneous degradation of the insulation vacuum. In<br />
particular, the application of short high voltage pulses to a<br />
set of ten magnet coils connected in series and simultaneously<br />
measuring the leakage current would detect any<br />
degradation. This option will be further detailed.<br />
3.3 Thermal Insulation<br />
Protection of the cold components against thermal radiation<br />
is achieved by actively cooled shields, high vacuum, and<br />
20 layers of reflecting foils. The fabrication of the panels for<br />
the plasma vessel uses a novel, patented technology to<br />
achieve the required narrow tolerance of ±2 mm. Epoxy<br />
impregnated glass fibre mats are joined with segmented<br />
copper meshes to achieve panels with good lateral heat conductivity<br />
while keeping eddy currents low. All 200 panels<br />
for the whole plasma vessel are available and put on stock.<br />
The holes for the ports and the fixation holes for the
mechanical supports on the plasma vessel are already integrated<br />
according to their actual position in the individual<br />
modules. The panels for the 1 st and 2 nd half-module of the<br />
plasma vessel have been mounted. Also 20 % of the panels<br />
of the 3 rd and 4 th half modules have already been mounted.<br />
Due to the narrow space the panels have to follow the surface<br />
of the plasma vessel at a close distance. Nevertheless<br />
several areas of the panels have to be adapted and cut-outs<br />
have been introduced on a case by case basis to avoid collisions<br />
with neighbouring components. The panels are kept at<br />
temperatures between 50 K and 80 K by cold helium gas.<br />
The panels of the ports and the outer vessel will be made<br />
from brass to limit eddie currents. All multilayer reflective<br />
shields are made from double side aluminised Kapton with a<br />
glass tissue spacer. During integration of the insulation,<br />
great care has to be taken to avoid gaps for heat radiation<br />
between neighbouring panels. The water pipes between the<br />
outer vessel and the plasma vessel also need to be insulated<br />
against the cold parts. Applying the thermal insulation onto<br />
these lines is a particular difficult task since these lines have<br />
a complicated three-dimensional shape and have to pass<br />
through narrow zones between the cold non-planar coils.<br />
3.4 Cryo-Piping<br />
Supply and collection of the cold helium gas of the nonplanar<br />
and planar coil windings, the coil casings, the coil<br />
support structure, the bus lines, the current leads, and the<br />
thermal insulation requires a complex pipe system with a<br />
total length of approx. 3000 m. The main supply from the<br />
magnet distribution box located underneath the cryostat is fed<br />
to eight ring lines inside the cryostat with inner diameters of<br />
16-36 mm. Approximately 460 branch lines with smaller<br />
diameters and lengths between 1 and 11 m connect the different<br />
cryogenic consumers with these ring lines. Routing of<br />
the cryo-lines around the magnet system has to consider<br />
movements of the coil headers during magnet ramping to<br />
avoid collisions with the bus lines and other neighbouring<br />
components and keep sufficient distance to the warmer thermal<br />
insulation. Allowance for the movements is achieved by<br />
flexible hoses. Since the coil casings are supplied in parallel<br />
their pressure drops can be manually adjusted and matched<br />
by 70 cryogenic control valves. A call for tender for the detail<br />
design and construction of the cryo-piping has been launched<br />
and the proposals are being evaluated. Since the cobalt content<br />
of the steel pipes must not exceed 500 ppm the material<br />
for the piping was ordered in advance and will be provided<br />
at the manufacturer’s disposal at the start of manufacture.<br />
3.5 In-Vessel Components<br />
The in-vessel components are the divertor target plates and<br />
baffles for energy and particle control, panels and heat<br />
shields to protect the plasma vessel against plasma radiation,<br />
control coils to modify the magnetic configuration at<br />
Wendelstein 7-X<br />
35<br />
the plasma boundary, cryo-pumps to control the neutral gas<br />
density during high-density plasma operation and supply<br />
lines for heat removal. Plansee SE is manufacturing the<br />
target elements, MAN DWE the wall protection panels and<br />
BNG the control coils. Assembly of the target modules<br />
from target elements as well as fabrication of the baffles, the<br />
heat shields, the cryo-pumps and of the supply lines is performed<br />
by the central technical services of <strong>IPP</strong> in Garching.<br />
All in-vessel components are fully tested in Garching<br />
(geometry, He-leak tests and hydraulic tests) before delivery<br />
to Greifswald (see figure 10). Several areas with different<br />
heat loads can be distinguished: The horizontal and vertical<br />
target modules of the high heat flux divertor are designed to<br />
withstand power fluxes up to 10 MW/m 2 . The baffles, which<br />
prevent the neutrals from re-entering the main plasma<br />
chamber, receive power fluxes of up to 0.5 MW/m 2 . The<br />
wall is subject to neutral particles and plasma radiation in<br />
the range up to 0.3 MW/m 2 . Following a critical review of<br />
the project scheduled during summer of <strong>2007</strong>, it was decided<br />
to start with a test divertor unit (TDU) without water<br />
cooling during the first operation period. The TDU shall be<br />
designed for short pulses at a maximum heating power of<br />
8 MW respectively a maximum absorbed heat of 80 MWs.<br />
The recovery time between pulses at maximal load shall be<br />
20 minutes. Since no deuterium operation is planned during<br />
the first operation period, the TDU can be built from standard<br />
stainless steel. In order to reduce the later effort to<br />
replace the TDU by the high heat flux divertor, all in-vessel<br />
components except the cryo-pumps will be installed from<br />
the beginning on. However, no water-supply will be provided<br />
for the cooling of the in-vessel components except for the<br />
control coils, and some special areas of the wall close to<br />
diagnostics and heating systems. The input parameters for<br />
the design are presently assessed in detail and fixed by a<br />
working group.<br />
Figure 10: Preparation of a wall protection panel for the hot leak test
3.5.1 Target modules<br />
The ten divertor units of the high heat flux target plates are<br />
designed to remove 10 MW convective stationary power<br />
load. Each unit consists of an area of 1.9 m² which is loaded<br />
up to 10 MW/m² and an intermediate area of 0.54 m² which<br />
is loaded only up to 1 MW/m 2 . Each divertor unit is assembled<br />
from several differently shaped target modules. The high<br />
loaded target modules are made up from sets of bar-like target<br />
elements which are supplied by cooling water in parallel and<br />
fixed on a common frame. The supports of these modules<br />
are adjustable within a range of a few millimetres to allow<br />
for compensation of manufacturing and assembly tolerances<br />
of the plasma vessel or uneven heat-loading during plasma<br />
operation. Armouring of the higher-loaded area requires<br />
890 target elements. Their surface must closely follow the<br />
3-D shape of the plasma boundary and will be machined<br />
before assembly of a module. 8 mm thick CFC tiles made of<br />
SEPCARB® NB31, produced by SNECMA Propulsion<br />
Solide, are joined to a water-cooled CuCrZr heat sink.<br />
During the pre-series activities, two types of bonding technologies<br />
were investigated: electron beam welding or hot<br />
isostatic pressing (HIP). The delivered SEPCARB® NB31<br />
material did not meet the specified mechanical properties;<br />
the material was, however, accepted based on the results of<br />
the tests of an additional pre-series. In order to optimize the<br />
manufacturing route and to reduce the stress at the interface<br />
between the CFC and the cooling structure, additional<br />
18 target elements were manufactured by Plansee SE applying<br />
different technologies. The different technologies comprised<br />
the addition of a compliant copper layer between the<br />
AMC ® interlayer and the CuCrZr heat sink by HIP (see<br />
figure 11), the reduction of the size of the CFC tiles to 1/2<br />
and 1/3 of the original tile width, and the rotation of CFC<br />
tiles and hence of the orientation of the ex-PAN fibres by<br />
90°. All these modifications were supported by numerical<br />
simulations. Extensive high heat flux tests in the GLADIS<br />
facility at <strong>IPP</strong> (see further information in section “Plasmafacing<br />
Materials and Components”) confirmed the benefit of<br />
the introduction of the compliant copper layer whereas the<br />
other modifications did not bring a significant advantage.<br />
However, metallographic examinations of the CuCrZr cooling<br />
structure revealed that a central blind weld between the<br />
cooling channels of the heat sink and the back plate gradually<br />
degrades during the cyclic load tests in GLADIS. This failure<br />
results in a by-pass flow between the cooling channels and<br />
hence reduced heat transfer. As a consequence the design of<br />
the cooling structure was improved and additional eight heat<br />
sinks and ten target elements were manufactured. High heat<br />
flux tests with the heat sinks of this pre-series in GLADIS<br />
were successful; the temperature distribution along the target<br />
elements fully agrees now with numerical simulations.<br />
The procedure for repairing of damaged target tiles shall be<br />
demonstrated by Plansee SE and will be qualified by testing<br />
Wendelstein 7-X<br />
36<br />
in GLADIS in 2008. The results of the high heat flux tests<br />
will also be used to correlate the GLADIS results with the<br />
predictions from infrared measurements carried out in the<br />
ARGUS facility of Plansee SE and in the SATIR facility of<br />
CEA-Cadarache. The correlation shall be the basis for the<br />
acceptance criteria of the target elements of the serial fabrication.<br />
The design of the divertor modules of the lower<br />
loaded area uses graphite tiles clamped on a CuCrZr heat<br />
sink with a graphite paper (Sigraflex) interlayer. Cooling is<br />
provided by stainless steel tubes brazed onto the backside of<br />
the heat sink.<br />
3.5.2 Baffle modules<br />
The baffle modules prevent back-streaming of the neutralised<br />
gas from the target plates. The design uses graphite<br />
tiles which are clamped on a cooling structure made of<br />
CuCrZr. Water cooling is achieved by stainless steel tubes<br />
which are brazed to the backside of the heat sink. The fixing<br />
screws for the graphite tiles are made from titanium zirconium<br />
molybdenum (TZM) alloy. So far about 30 % of the<br />
cooling structures have been manufactured by the <strong>IPP</strong> workshop<br />
in Garching, and the second lot of graphite tiles has<br />
been ordered.<br />
3.5.3 Wall protection<br />
About 70 m² of the plasma vessel surface is covered by<br />
double-wall stainless steel panels with integrated watercooling.<br />
The second series of 90 panels has been formed by<br />
MAN DWE and is in the final stage of assembly. The channels<br />
within the panels are formed by hydraulic pressing with<br />
approximately 100 bar. In the areas, where ports have been<br />
omitted the plasma vessel will be closed by appropriate steel<br />
plates. Since manufacture of the wall panels is already well<br />
advanced and most of the panels are already in different<br />
stages of manufacture, some areas of the plasma vessel will<br />
not be protected by wall panels during the first operation<br />
phase. During later replacement of the divertor, also some<br />
wall panels have to be replaced in order to also protect the<br />
open spaces. . The inner wall of the plasma vessel is protected<br />
by heat shields. These heat shields use graphite tiles which<br />
are clamped to a cooling structure in a similar same way as<br />
for the baffles. The design has to integrate also several plasma<br />
diagnostic components as well as an NBI beam stopper and<br />
a mirror for ECR heating. By the end of <strong>2007</strong> 50 % of the<br />
cooling structures have been fabricated in the <strong>IPP</strong> workshops.<br />
During steady state and full power plasma operation,<br />
the inner surfaces of the ports need to be protected in the<br />
same way as the plasma vessel. For budgetary reasons, construction<br />
of the port protection panels has been postponed to<br />
a later date. Nevertheless, the design of these protection<br />
elements was continued to fix their interfaces and define the<br />
rooting of the cooling water lines. Since the space behind the<br />
wall protection is very restricted, all port protection panels
will be later supplied from outside. The NBI ports as well as<br />
the port for the diagnostic injector need to be protected<br />
against energetic particles by graphite tiles right from the<br />
beginning on. Due to the spatial constraints these areas need<br />
a sophisticated design. Design studies for both areas have<br />
been started.<br />
3.5.4 Cryo-pumps<br />
Ten cryo-pumps are located behind the target plates and<br />
allow increasing the pumping capacity for hydrogen and<br />
deuterium up to 75 m 3 /s during high-density plasma discharges.<br />
The cryo-pumps are composed of a cryo-panel<br />
cooled with single phase helium, a Chevron baffle cooled with<br />
liquid nitrogen and an additional water cooled baffle. Fabrication<br />
of the cryo-pumps is well advanced (see figure 11).<br />
Figure 11: Main parts of a cryo-pump unit<br />
The cryo-pumps will be installed only after the first operation<br />
phase. Hence fabrication activities were slowed down<br />
and are now only continued in the Garching workshops on a<br />
fill in basis. According to the original design the two pumping<br />
units behind a divertor target would be integrated as one unit<br />
together with the interconnecting cryo-line during assembly<br />
of the plasma vessel. This would have allowed performing a<br />
cold leak-test of the whole unit outside W7-X before assembly.<br />
Since the pumping units shall now be assembled at a<br />
later stage the cryo-line must be separated to allow insertion<br />
of the units into the plasma vessel through a port opening<br />
and joining the cryo-line inside the plasma vessel.<br />
3.5.5 Control coils<br />
Ten control coils will be installed behind the baffle plates.<br />
These coils will be used to correct small field errors at the<br />
plasma edge, to optimize the position and extent of the islands<br />
and dynamically sweep the power across the target plate.<br />
Wendelstein 7-X<br />
37<br />
The coils are supplied by the company BNG. Each coil is<br />
made of eight turns of a hollow copper conductor and is<br />
water cooled. By the end of <strong>2007</strong> all ten coils have been<br />
manufactured and six coils have been tested and accepted<br />
(see figure 12). The first two coils have been delivered to<br />
Greifswald and will be used for assembly trials and a test of<br />
the power supply units.<br />
Figure 12: Functional test of a control coil with integrated current leads<br />
3.5.6 Supply lines inside the plasma vessel<br />
Cooling of the in-vessel components is provided from the<br />
main water system through 80 supply ports in the different<br />
W7-X modules. The interface between the supply lines and<br />
the cooling loops inside the plasma vessel is realised by<br />
plug-ins. The water cooling loops inside the plasma vessel<br />
comprise a very complex network with a total length of<br />
about 4000 m. Routing of the water pipes has to consider the<br />
3D-shape of the plasma vessel, pass around a high number<br />
of port openings for diagnostics and heating systems, take<br />
into account the restricted space behind the wall protection<br />
panels, and identify appropriate attachment points. In addition,<br />
the design of the cooling circuits has to consider many<br />
interfaces with the diagnostics and heating systems. The<br />
detail design of the pipe work is supported by manufacture<br />
and trial assembly of full-scale prototypes of the cooling<br />
loops. First prototype loops have been manufactured by <strong>IPP</strong>.<br />
Assembly trials are performed in a wooden mock-up of the<br />
plasma vessel which was moved from Greifswald to<br />
Garching.<br />
3.6 Refrigeration System<br />
The refrigeration system has an equivalent peak power of<br />
7 kW at 4.5 K to supply the magnet system the thermal<br />
shields, the current leads and the cryo-pumps with helium<br />
at different temperatures and pressures. Linde Kryotechnik<br />
AG is in charge of the delivery of the helium refrigerator.
The refrigeration process was designed for an operation<br />
scheme where the superconducting coils are energised at<br />
nominal current only during the day. Over night and during<br />
the days of idle operation the plant would run in different<br />
standby modes. To allow economic operation the excess<br />
plant capacity during standby modes is used to liquefy helium<br />
into a 10,000 l storage tank. During full power W7-X operation<br />
helium is taken from the storage tank to boost the<br />
refrigeration power. The change from low-Tc superconducting<br />
current leads to high-Tc current leads reduces the<br />
amount of helium from the storage tank and hence allows<br />
continuous operation of W7-X at nominal magnetic induction.<br />
Such an operation mode is preferred since it reduces<br />
the number of load cycles of the magnet system and hence<br />
the risk of fretting of the sliding support elements between<br />
the non-planar coil casings. The main helium transfer line<br />
between the refrigerator and the magnet valve box has been<br />
manufactured and assembled on site by DeMaCo, a subcontractor<br />
to Linde Kryotechnik AG. This transfer line has a<br />
total length of 54 m and houses 6 supply and return lines<br />
with nominal diameters between 20 and 80 mm. Manufacture<br />
of the two refrigerator cold-boxes, the sub-cooler,<br />
the two compressors, the gas purification system and of the<br />
magnet valve box was finished. After delivery to Greifswald<br />
assembly of the main components and installation of<br />
the warm piping are ongoing in accordance with schedule.<br />
Commissioning of the helium refrigerator will start in early<br />
summer. A software program was developed allowing<br />
simulation of steady state operation of the W7-X refrigerator.<br />
This program models 14 heat exchangers, seven<br />
expansion turbines, two cold compressors, a cold circulation<br />
pump and two screw compressors. The characteristic<br />
parameters of the heat exchangers and the machinery were<br />
adjusted to the results of the main operation modes from<br />
the Linde process layout. This simulation program will be<br />
checked against real operation parameters during commissioning<br />
and allows predicting steady state capacities and<br />
power consumption during later operation. The liquid nitrogen<br />
system of the branch institute consists of a 30,000 l<br />
tank and a distribution system. In <strong>2007</strong> approx. 80,000 l of<br />
liquid nitrogen were provided for the ECRH system, the<br />
cryo-laboratory, W7-X assembly and other users within the<br />
institute.<br />
4 Engineering<br />
The sub-division Engineering (EN) emerged in April <strong>2007</strong><br />
from the former System Engineering (SE) sub-division; it<br />
provides engineering support to the Wendelstein 7-X project.<br />
EN is organized in three departments: Design Engineering<br />
(DE), Development and Test (DT), and Instrumentation<br />
(IN). The report encompasses also the earlier activities in<br />
<strong>2007</strong> which were accomplished within the SE sub-division.<br />
Wendelstein 7-X<br />
38<br />
4.1. Design Engineering<br />
4.1.1 Structural analysis<br />
DE continued to investigate the mechanical behaviour of<br />
structural components of W7-X during various modes of<br />
operation. Since the whole structure is by far too complex to<br />
be described in detail by a single finite element (FE) model,<br />
it is necessary to use coarse global and detailed local models.<br />
The latter can be run independently with boundary conditions<br />
extracted from the global models (GM). Two separate<br />
global models are necessary for the whole W7-X basic<br />
machine structural analysis: the magnet system global model<br />
and the cryostat global model. The global models include<br />
elastic material properties only; however, they take into<br />
account nonlinearities like friction and gaps. Theoretical and<br />
experimental crack propagation studies were continued and<br />
different FE-tools were tested for crack evaluation. Steel<br />
casting defects as well as cracks in welds and weld influence<br />
zones were evaluated using analytical and semi-empirical<br />
methods. The latter were also applied for defining weld<br />
quality criteria.<br />
4.1.1.1 Magnet system global analysis<br />
The magnet system GM encompasses the non-planar and<br />
planar coils (NPC and PLC, resp.), the central support structure<br />
(CSS) including the extensions for the coil supports,<br />
and the inter-coil support structure. The latter comprises the<br />
“narrow support elements” (NSE) on the high field side<br />
between non-planar coils, the “lateral support elements”<br />
(LSE) on the low field side between the non-planar coils,<br />
the ”contact elements“ (CTE) between the half-modules and<br />
modules, and the ”planar support elements” (PSE) between<br />
planar and non-planar coils. The narrow and part of the<br />
planar support elements as well as the CTE basically consist<br />
of sliding Al-bronze pads held by steel pad frames, and corresponding<br />
sliding steel counter-faces. The highly loaded<br />
interfaces between the CSS and the coils are provided by<br />
complex bolted and wedged flange connections which partially<br />
open during operation, the so-called central support<br />
elements (CSE). Due to this complexity including many<br />
frictional sliding elements, the magnet GM behaves extremely<br />
nonlinear and is very sensitive to variations of initial<br />
parameters and boundary conditions. In order to get sufficient<br />
confidence in the results, two independent global<br />
FE-models have to be provided. Due to different parallel<br />
developments and special requirements, currently three GMs<br />
are under development and use. They are implemented in<br />
different commercial FE packages: ADINA GM, ANSYS<br />
GM, and ABAQUS GM, respectively. Early versions of the<br />
ADINA GM were for many years the only tools for the<br />
magnet structure design. It is now being recreated from<br />
scratch with partial support of the company IBK. The model<br />
is completely independent from the two others: Contrary to<br />
them, all the coil housing and intercoil support elements are
eing created quite detailed in one piece with contact interfaces<br />
only at places where such ones are also in reality. The<br />
ADINA GM is expected to be the most accurate and fastest.<br />
However, the modelling is not finally finished, the central<br />
support structure including the interfaces to the coil still<br />
have to be completed before an extended test and benchmarking<br />
phase can start. The model is now expected to be<br />
fully operational in the second half of 2008. The ANSYS GM<br />
as the main FE-tool was created in the last years with first<br />
priority with the help of the Efremov <strong>Institut</strong>e. The development<br />
activities, i.e. continuous updating and improvement<br />
of the model, are still ongoing at <strong>IPP</strong>; however, the contract<br />
with Efremov <strong>Institut</strong>e was closed. Both versions of this GM,<br />
the half module model with boundary conditions representing<br />
the stellarator symmetry (so-called 36° model) as well as<br />
the full module model (so-called 72° model including also<br />
the cryolegs) with cyclic boundary conditions are the workhorses<br />
which are heavily used for all kind of magnet system<br />
analyses. The 72-degree model is applied for analysing<br />
effects which are not in accordance with the stellarator symmetry<br />
like the presence of cryolegs and the dead weight.<br />
However, the module model requires enormous resources.<br />
One run takes typically one week for full load history which<br />
includes bolt preload, dead weight, cool-down, EM force<br />
application, and optionally the effect of winding pack (WP)<br />
embedding. The presence of the cryolegs and the deadweight<br />
result in 5-20 % asymmetry in the displacements<br />
and support forces between neighbouring 36-degree semimodules.<br />
In addition, the rigid body toroidal movement of<br />
the Magnet system is induced by the central structure deformation<br />
and corresponding tilting of the cryolegs. The<br />
ABAQUS GM emerged from a simplified model used for<br />
predicting magnet system deformations during different<br />
assembly steps – the results had to be considered for assembly<br />
procedures and tools. Starting from this basic model it took<br />
relatively small effort by LTC comp. to create a 36° version<br />
of GM in 2006 and a 72° version until the end of <strong>2007</strong>. The<br />
model is now installed at the <strong>IPP</strong> Greifswald and first structure<br />
analysis confirmation runs have been started. The model<br />
benchmarking with ANSYS GM shows good agreement<br />
of the main results. Minor discrepancies are still under<br />
checking and verifications in both GMs. ABAQUS will also<br />
be used for special tasks for which this program is better<br />
suited (e.g. for strength limit analyses which requires elastoplastic<br />
material properties and option of large deformations).The<br />
main GM applications are calculation of main<br />
stresses, deformations and forces/moments in the main<br />
structural elements occurring during different modes of<br />
operation such as bolt tightening already at room temperature,<br />
applying dead weight, cooling to cryogenic temperatures,<br />
and applying the electromagnetic forces. Also the<br />
influences of the winding pack embedding pre-stresses,<br />
different friction factors at the gliding elements, tolerance<br />
Wendelstein 7-X<br />
39<br />
deviations, NSE and PSE gap variations, etc., can be simulated.<br />
The GM is also used for prediction of handling deformations<br />
during assembly. A further application of the GM<br />
was the definition of positions for the mechanical instrumentation<br />
of the structure.<br />
Figure 13: Over-spreading of non-planar coils to install oversized lateral<br />
support block for weld shrink compensation; deformation in mm.<br />
The original study of the Magnet system behaviour and optimization<br />
of the parameters was performed for four main<br />
plasma scenarios with maximum current in different coils,<br />
corresponding to an on-axis field of 3 T. Preliminary analysis<br />
of the remaining 5 operational scenarios reveals that due to the<br />
high nonlinearity of the system some of the supports might<br />
be loaded to the limits already at plasma axis fields somewhat<br />
below the maximal design value of 3 T, therefore the<br />
operation limits in particular for these additional scenarios
have to be explored in the future. In order to reduce the<br />
number of full cycles for the machine, the switch from one<br />
operation scenario to another without unloading to the zero<br />
current has been approved for the project. The corresponding<br />
GM analyses confirm that the main response is within a<br />
5 % range of the previously considered corresponding zeroto-maximum<br />
cycles.<br />
4.1.1.2 Detailed analysis of magnet system components<br />
Using input data from the global models, a number of local<br />
FE models have been developed that scrutinize in detail the<br />
behaviour of the selected components. These local models<br />
were generated and are being refined and updated at <strong>IPP</strong><br />
and by other institutes in the framework of international<br />
contracts:<br />
• Forschungszentrum Jülich (FZJ): bus system (ongoing);<br />
• Warsaw Technical University (WUT): central support elements<br />
(ongoing);<br />
• CEA/CRIL Technology (France): central support ring<br />
(contract closed in <strong>2007</strong>), coil header deformation (ongoing)<br />
• ENEA (Italy): lateral supports between coils 5-5 (contract<br />
closed in <strong>2007</strong>)<br />
• Efremov <strong>Institut</strong>e (St. Petersburg): winding pack analysis<br />
(contract closed in <strong>2007</strong>)<br />
Most of the final structural component designs were implemented<br />
in the global and local models. In the course of this<br />
work global and local analyses proceeded iteratively with<br />
design changes until convergence was reached.<br />
4.1.1.2.1 Coils<br />
The updated insulation material properties and GM deformation<br />
data for PLC and NPC winding pack analysis were<br />
collected during <strong>2007</strong> in order to complete the local study<br />
of the most critical WP zones. In addition, a special submodelling<br />
procedure for this task was developed in collaboration<br />
with the Efremov <strong>Institut</strong>e. The conservative consideration<br />
of the coil housing defects as cracks, and fast<br />
crack growth analysis confirm that the accepted defects<br />
investigated so far are tolerable with sufficient margin.<br />
The detailed analysis of the bolted PSEs described below<br />
indicated that the PLC case of type A had to be reinforced<br />
by additional pins. The location and number of pins were<br />
defined, and reinforcements were completed in <strong>2007</strong>. The<br />
analysis of coils in self field was performed in order to verify<br />
coil modelling and strain gage measurements at CEA<br />
Saclay. The program to achieve better understanding of<br />
stick slip phenomena and dynamic behaviour of the magnet<br />
system was continued. Dynamic FE studies regarding the<br />
effect of stick slips of NSE and CSE gliding surfaces were<br />
performed internally and with support of KRP and LTC<br />
comps. Further investigations in preparation of the socalled<br />
”MQ-test” (s. below) dealt with the detail impulse<br />
transfer from a pendulum hammer via a steel rod to the coil.<br />
Wendelstein 7-X<br />
40<br />
The design of the trim coils was supported by structural<br />
analysis with finite element calculations.<br />
4.1.1.2.2 Central support structure (CSS)<br />
FE-studies were performed to determine sliding and displacements<br />
of the half-module and module connection<br />
flanges considering a realistic friction factor range. With<br />
these results, the flange shear pins were finally defined, and<br />
the connection bolt loads specified. Some bolts needed to<br />
be modified and re-analysed in order to avoid collisions<br />
with ports. Further analyses were also performed to assess<br />
non-conformities, detail design changes, and weld modifications.<br />
4.1.1.2.3. Cryolegs<br />
A final design change of the cryolegs based on shrink-fitting<br />
the fibre glass reinforced epoxy tube into a steel flange<br />
assembly was proposed, and corresponding design calculations<br />
were performed. Consecutive calculations accompanied<br />
the material development and detail design of the<br />
cryolegs. This work was very time consuming due to the<br />
fact that the 72° GM had to be used in many runs. Towards<br />
the end of the year the final material data were provided by<br />
the manufacturer and confirmed by FE-analysis. The detailed<br />
cryoleg analysis also revealed that one of the cryoleg<br />
support toroidal tie rod could be omitted. Further analysis<br />
work is foreseen accompanying the component test program<br />
and detail design.<br />
Figure 14: Analysis of a cryoleg under design loads
4.1.1.2.4 Central support elements (CSE)<br />
Each coil is suspended on the central support structure via<br />
two bolted connections between blocks as part of the coil<br />
housings, and extensions of the central support structure.<br />
These connections are typically made of a thick single or a<br />
matrix of up to nine long and elastic Inconel 718 rods to<br />
obtain a preload of 650-900 MP a per bolt at 4 K. Stainless<br />
steel wedges are inserted between the coil blocks and the<br />
shoulders of the CSS extension flanges. The wedges, according<br />
to a new design, are welded onto the coil blocks by<br />
two weld seams each (instead of previously one). The detail<br />
analysis continued in close cooperation with Warsaw<br />
University of Technology. Extended models were completed<br />
for the complex triple and double connections NPC2-Z2 +<br />
NPC3-Z2 + NPC4-Z2 and NPC1-Z1 + PLCA-Z1, respectively,<br />
the new weld design for the wedges was confirmed,<br />
and wedge installation procedures were defined with developed<br />
parametric model of typical CSE. The process of<br />
creation parametric models for all critical CSEs is on-going.<br />
The set of such models allows to analyse variation of parameters<br />
(e.g. tolerances) of components like wedges or shims<br />
during assembly.<br />
4.1.1.2.5 Lateral support elements (LSE)<br />
The lateral support elements are located on the low field<br />
outboard side and transmit tensile, compressive and shear<br />
forces up to 1.7 MN, and bending moments up to 200 kNm,<br />
resp. For the non-planar coil pairs 1-1, 1-2, 2-3, 3-4, 4-5 the<br />
limited space permits welded solutions only. For the LSE<br />
between the coils 5-5 at the module boundary a bolted solution<br />
was adopted. The lateral support element weld dimensions<br />
were finally defined, and the basic design of the bolted<br />
LSE 5-5 at the module interface was completed. The functional<br />
specifications were issued. During assembly quick<br />
assessments concerning cracks and material imperfections<br />
were performed which led to continuation of assembly without<br />
significant interruption.<br />
4.1.1.2.6 Narrow support elements (NSE)<br />
The narrow support elements are sliding contacts (~30 per<br />
half module), located on the high field inboard coil side.<br />
They transmit forces up to 1.5 MN between adjacent coils<br />
while simultaneously allowing relative coil movement up to<br />
5 mm when in contact, and relative coil tilting up to<br />
1 degree. In many cases there is a small initial gap in the<br />
range from 0.2 mm up to 4.5 mm between the sliding surfaces<br />
which close gradually during the coil current ramp-up.<br />
The optimization and definition of the NSE gap widths was<br />
an ongoing issue where the analysis results had to be ready<br />
in correspondence to the assembly schedule. On the other<br />
hand, fixing of these sensitive distances was delayed as long<br />
as possible in order to have the most recent FE model and<br />
design updates available. By end of the year this tedious<br />
Wendelstein 7-X<br />
41<br />
work was done and all gaps for the NSEs inside of the halfmodules<br />
were defined. The tilting of the NSE surfaces<br />
against each other during loading adds a considerable sliding-rolling<br />
path length to the pure relative translational coil<br />
shift. Therefore, pre-tilting in opposite direction was introduced<br />
for the NSEs with large tilting angles. The corresponding<br />
algorithm was developed and implemented in the<br />
design and manufacturing procedure.<br />
4.1.1.2.7 Planar support elements (PSE)<br />
The planar supports fix the planar on top of the non-planar<br />
coils. Most of the PSEs are sliding elements with designs<br />
similar to the sliding NSEs, allowing relative coil movements<br />
up to 10 mm when in contact.<br />
Figure 15: Fixed planar coil support elements; stress intensity in MPa<br />
(bolt preload + EM forces in HJ regime)
They have to transmit forces up to 500 kN and to reduce<br />
PLC deformations to tolerable values. A final solution was<br />
found for the fixed supports of the planar coils which replace<br />
one of the previously foreseen sliding elements per coil.<br />
4.1.1.2.8 Contact elements (CTE)<br />
The contact elements are, similarly to the NSEs, sliding<br />
supports between half-module and module interfaces which<br />
transmit compression forces via MoS 2 – coated Al-Bronze<br />
Pads and steel counter-surfaces. In contrary to the NSEs,<br />
the gap width adjustment is possible only after final positioning<br />
of the half-modules and modules, resp., which<br />
requires special provisions. The designs of the contact elements<br />
were finally frozen, and a functional specification<br />
was issued.<br />
4.1.1.2.9 Current lead fixing box<br />
The current lead support structure (“fixing box”) was modelled<br />
and analysed at the <strong>IPP</strong>, and incorporated in the global<br />
model of the bus-bar system (FZJ, Jülich). The optimisation<br />
of the structure is still on-going.<br />
Figure 16: Analysis of current lead fixing box; deformation in mm<br />
4.1.1.3 Cryo piping<br />
FE-modelling (in ANSYS) of the cryo-pipe work for the<br />
first module to be assembled has started in close cooperation<br />
with the design group. The aim of this work is to determine<br />
Wendelstein 7-X<br />
42<br />
mechanical loads and deformations of the complex piping<br />
system as a consequence of the magnet system movements<br />
during cool-down and magnet excitation.<br />
Z<br />
X Y<br />
Figure 17: Finite element model of cryopipe system for module 5<br />
4.1.1.4 Cryostat<br />
The ANSYS FE cryostat global model refinement and<br />
update in cooperation with IGN and ENEA (cooperation<br />
was closed in <strong>2007</strong>) is practically completed, and the model<br />
is operational from the beginning of 2008. The final update<br />
was a consequence of the Scenario 3 implementation which<br />
requests omission of 45 ports. Concerning the improved<br />
horizontal plasma vessel (PV) support system, the common<br />
work of <strong>IPP</strong> and Rostock University on a procedure for controlled<br />
adjustment and shaping of the plasma vessel within a<br />
range of ±10 mm was completed. The result is an iterative<br />
approach using the algorithm of Rostock and the cryostat<br />
GM of <strong>IPP</strong>. An accuracy of
Figure 18: Framed outer vessel upper half shell during lifting and turning<br />
over; deformation in mm<br />
injection area for shield design, and AC modelling and simulations<br />
for coil impedance spectrum tests. Under participation<br />
of EN, a project was initiated to create a full magnetic<br />
field model including all uncertainties during the machine<br />
construction and their treatment with a Bayesian approach.<br />
It is intended to accompany all steps of assembly and to<br />
identify critical deviations from the stellarator symmetry in<br />
time and to assess potential correction measures.<br />
4.1.3 Scenario 3 studies<br />
Calculations of different power deposition and cooling scenarios<br />
of the in-vessel components were performed in order<br />
to decide on a simplified design of the Test Divertor Unit<br />
(TDU) and the other components within the PV. As a main<br />
result it was found that under the reduced Scenario 3 performance<br />
requirements a passively (i.e. only radiatively and<br />
Wendelstein 7-X<br />
43<br />
conductively) cooled TDU and liner operation is possible.<br />
Detailed investigations and determination of operational<br />
limits are ongoing.<br />
4.2 Development and Test<br />
4.2.1 Coil support elements<br />
The test program in support of the development work was<br />
basically completed; however, further tests are still required<br />
for final design confirmations, definition of operation limits,<br />
for qualification of new materials, and for preparing decisions<br />
concerning non-conformities.<br />
4.2.1.1 Central support elements<br />
The functional specification of the CSEs was issued, including<br />
the tolerances which sensitively influence the wedge<br />
loads. A special assembly and measurement procedure for<br />
the critical wedges was developed together with the subdivision<br />
Assembly. For those CSEs where flanges open during<br />
operation, a MoS 2 coating procedure was set up in cooperation<br />
with Assembly. Another 3-bolt test was performed.<br />
This full scale mock-up of one third of the critical 3×3 bolt<br />
connection NPC1-Z1 took into account the new wedge<br />
design, wedge welding procedure, the experimentally determined<br />
weld shrink, and the specified tolerances. The counter-surfaces<br />
on the CSS extension shoulders were lubricated<br />
with MoS 2 spray corresponding to the procedure applied to<br />
the NSEs. The cycle number (≈3900 in LN 2 ) and load<br />
sequence was similar to the first test performed in 2005.<br />
However, more elaborate instrumentation was installed in<br />
order to distinguish relevant stick slip events of the sample<br />
from those of the test bed. First stick slips which could be<br />
attributed to flange opening occurred only after 3240 cycles<br />
at 90 % of full load (corresponding to 90 % of 3T-Operation),<br />
earlier weaker acoustic events could unambiguously<br />
identified by triangulation as originating from other parts of<br />
the equipment. At the previous 3-bolt test heavy stick slip<br />
was audible after about 1000 cycles, however, there were no<br />
means to retrace its origin. After both tests the sample<br />
wedges and shoulders showed similar friction traces. Final<br />
conclusions are not yet drawn, the evaluation is still ongoing.<br />
But as a consequence, in W7-X the wedge as well as the<br />
counter-surfaces on the critical CSS extension shoulders<br />
were specified to be MoS 2 -coated.<br />
4.2.1.2 Sliding element contacts<br />
Even though the NSE, PSE and CTE sliding surface coatings<br />
had been decided already, some tests had to be performed<br />
for investigation of manufacture non-conformities,<br />
and clarification of open issues like ageing, break loose,<br />
and tilting effects. For such studies, and since changes and<br />
non-conformities are expected throughout the W7-X construction<br />
period, a setup for scaled down sample tests was<br />
installed at BAM in Berlin. The scaled pads with 23 mm
diameter (instead of originally 73 mm) and a surface curvature<br />
radius of 350 mm (instead of 1100 mm) are loaded with<br />
the same stresses and strains as the full sized ones by applying<br />
only 10 % of the compression force. The scaling is based<br />
on extensive FE calculations. With the BAM equipment,<br />
experiments can be performed much cheaper and quicker as<br />
with the full size samples which were necessary during the<br />
development phase. An additional advantage of the BAM<br />
test bed is its suitability for experiments in liquid helium.<br />
However, for achieving completely realistic environment<br />
conditions, the equipment needs to be upgraded for vacuum<br />
operation at 5 K and 80 K. The tests performed so far did<br />
not completely confirm the previous full scale tests at KRP<br />
which were done in vacuum at 80 K. Surprisingly, no stick<br />
slip occurred during tests in LN 2 up to 15000 load cycles,<br />
but stick slip was immediately present at the experiments in<br />
LHe and ceased after about 50 cycles. This behaviour was<br />
the same for MoS 2 -sprayed and -burnished counter-sides. In<br />
order to clarify this issue tests in vacuum at these temperatures<br />
would be necessary, however, the complete test program<br />
is not yet finally decided. Systematic pad and counterside<br />
MoS 2 layer ageing experiments were started in order to<br />
estimate possible impact of the long exposure to air during<br />
W7-X assembly. In order to reduce such ageing risks, in the<br />
assembly as well as the torus hall the air humidity is kept<br />
below 50 %. NSE pad and counter-side layer application<br />
was supervised, and non-conformities were evaluated as<br />
well as corresponding decisions prepared. In this context a<br />
specification for tolerable defect sizes of sliding surfaces<br />
was created.<br />
4.2.2 Coil quench experiment<br />
Detailed preparation of the intended experiment to mechanically<br />
excite a non-planar coil by hitting it in cryogenic environment<br />
under self-field magnetic load was started after<br />
general consent for such an experiment was achieved within<br />
<strong>IPP</strong>, with CEA Saclay, and with the coil manufacturer BNG.<br />
The basic experimental procedure was decided, and preparatory<br />
experiments were started. The real mechanical quench<br />
experiment in Saclay is planned for autumn 2008 within an<br />
available time window of the coil test schedule.<br />
4.2.3 Materials<br />
The material data base was maintained and continuously<br />
supplemented as an ongoing activity. Cryogenic tensile tests<br />
of welds and weld influence zones of cold- and warm-hardened<br />
aluminium alloy conductor jacket material were done.<br />
Orthotropic mechanical characteristics (stress-strain as well<br />
as thermal contraction) of fibre-glass epoxy samples of the<br />
bus-bar weld joint insulation were determined at liquid<br />
helium temperature. Microstructure investigations and cryogenic<br />
tensile tests were performed on a new Al-bronze alloy<br />
for NSE/PSE/CE pad material, and further low temperature<br />
Wendelstein 7-X<br />
44<br />
pulling tests on high-quality steel (1.4429 ESU) for highly<br />
loaded NSE pad frames. All these cryogenic tests were carried<br />
out at the FZK. Collection and classification of coil<br />
housing cast defects was almost completed.<br />
4.3 Instrumentation<br />
New strain gauge sensors with reduced temperature dependence<br />
in cryogenic environment were introduced together<br />
with copper plated steel compensation blocks for mechanical<br />
structure instrumentation. This system was tested on<br />
the non-planar coil AAB12 in Saclay and showed good<br />
agreement with predictions from FE-calculations. Instrumentation<br />
of the CSS with these sensors has started. The<br />
extreme mechanical loads on the complex, non-linear magnet<br />
structure necessitate its monitoring during operation. This<br />
information about the mechanical behaviour has also to be<br />
gathered for adaptation of the finite element models to the<br />
as-built material and geometry characteristics in order to<br />
define operational limits of the machine and evaluate possible<br />
abnormal behaviour. An adequate structure instrumentation<br />
concept, based on mechanical analysis results, was<br />
defined. The complete mechanical measurement system<br />
relies upon strain gauges which, besides measuring stress<br />
and strain, will also be used in combination with specially<br />
developed equipment to indicate component deformations<br />
and relative movements. Collision monitoring in critical<br />
areas of ports and the coil header regions will be done<br />
with single contact foils. A strain gauge system including<br />
the corresponding data acquisition equipment was adapted<br />
for dynamic measurements which is required for the<br />
mechanical quench experiment. Much work was also spent<br />
on collection, analysis, and interpretation of strain measurement<br />
results of the CEA Saclay coil tests. This study finally<br />
confirmed the functionality of the pre-existing strain gauges<br />
on the non-planar coils. The suitability of the already assembled<br />
PLC strain gauges, or necessity to exchange them, is<br />
still under discussion, corresponding investigations are<br />
ongoing.<br />
5 Design and Configuration<br />
The subdivision ”Design and Configuration” was established<br />
in summer <strong>2007</strong> to adapt the organisation of the W7-X<br />
project to the increasing assembly activities. In order to support<br />
these activities it was considered necessary to establish<br />
the department ”Configuration Management”. The purpose<br />
of this department was to speedily implement component<br />
changes caused by design changes and to properly keep<br />
track of fabrication errors. In the past some of these tasks<br />
where taken care of within the department System Coordination.<br />
The number of components within the cryostat, the<br />
complexity of their arrangement and the multitude of relative<br />
movements possible in the various operational modes
led to the establishment of the department ”Configuration<br />
Control” whose tasks became to ensure collision-free operation<br />
at all times. These two new departments were combined<br />
with the department ”Design Office” under the umbrella of<br />
one subdivision in order to simplify fast and effective collaboration<br />
between departments that naturally interact<br />
strongly with one another. After about a half year of operation<br />
this organisation has shown its effectiveness in supporting<br />
the device assembly on all aspects by implementing well<br />
defined fast and transparent work flows with a clear distribution<br />
of responsibilities and comprehensive and up-to-date<br />
documentation.<br />
5.1 Configuration Management<br />
The department Configuration Management (DC-CM) plans,<br />
implements and leads the processes that are required to<br />
ensure permanent consistency between the requirements of<br />
the W7-X system specification and the performance attributes<br />
of its components throughout the life time of the<br />
project. The detailed tasks of DC-CM are oriented at the<br />
common standards of configuration management (CM).<br />
CM for W7-X is being implemented with most efficient use<br />
and interlink of existing processes (change request, nonconformances,<br />
interface control, collision control) and tools<br />
(KKS project structure, the PLM-system, data bases).<br />
5.1.1 Change Management<br />
Change Management (CM) controls all change processes,<br />
preserves configuration control at the interfaces, ensures<br />
documentation and consistent implementation in the configuration<br />
of all changes and variances, and provides orderly<br />
communication of change information within the project.<br />
This includes that CM enables change and non-conformance<br />
decisions to be based on the knowledge of complete<br />
change impact. Processes are controlled via a data base.<br />
Highest priority is given to fast handling of change and<br />
non-conformance processes which are time-critical and<br />
might affect the schedule of device assembly. These are<br />
actively guided and driven by CM and thus accelerated.<br />
CM supports preparation and documentation of the configuration<br />
control board (CCB) meetings and the implementation<br />
of its decisions.<br />
5.1.2 Configuration Status Accounting<br />
A PLM-based concept for the W7-X system documentation<br />
has been implemented. It will give access to the complete<br />
configuration information and finally replace the previous<br />
system specification. A central master document for each<br />
W7-X component, the so called loose leaf book, provides<br />
the description of the function of a component and its positioning<br />
in the project structure and the CAD assembly.<br />
Additionally, the loose leaf book is a navigation tool (via<br />
references in the document and links in the PLM system)<br />
Wendelstein 7-X<br />
45<br />
to access specifications, data sheets, interface descriptions,<br />
design changes, and variances that result from non-conformances.<br />
Provision of interface descriptions and accounting<br />
for change impacts across the interfaces is coordinated by<br />
CM. Masses, materials and their composition are documented<br />
for all components within the torus hall in a material<br />
data base. Additionally, the data base documents the certified<br />
relative magnetic permeability of the materials used and<br />
their certified cobalt content as a basis for assessment of<br />
magnetic field errors and to keep track of the amount of<br />
cobalt, which is limited by the authorities due to its high<br />
neutron activation rate.<br />
5.2 Configuration Control<br />
The main missions of the department Configuration<br />
Control (CC) are to ensure collision-free operation of W7-X<br />
for all modes of operation and to coordinate the space<br />
requests of peripheral components in the torus hall and<br />
adjacent buildings. This is being accomplished by developing<br />
the required tools for generating and book-keeping of<br />
the CAD models of the relevant components by performing<br />
the collision checks and finally by initiating and leading the<br />
processes required to eliminate detected conflicts in collaboration<br />
with CM. W7-X is undoubtedly a device with<br />
high geometrical complexity. Especially in the cryostat one<br />
has to deal with three-dimensional free-form shapes of the<br />
coils snugly located between the heat shields of the thermal<br />
insulation of the plasma vessel and the ports, the coil support<br />
structure the meandering lines of the bus-bars and the cryogenic<br />
helium supply, the diagnostic and quench detection<br />
cables and all the required supports and additional components.<br />
Figure 19 illustrates this situation in the cryostat.<br />
Figure 19: Module 5 of the cryostat (outer vessel shell omitted)
Even at room temperature it is already quite difficult to<br />
ensure that none of these components collides with another<br />
since with the used W7-X CAD system CADDS5 only a<br />
small subset of all the components can be studied at one<br />
time. This situation becomes even more challenging if one<br />
wants to take into account the actual geometry of the fabricated<br />
components, the relative movement of the components<br />
under the various loads of operation (configurations),<br />
i.e. baking of the plasma vessel, cool-down of the cryostat,<br />
various magnetic field configurations as obtained from<br />
finite element analysis (FEA). In order to cope with this<br />
complexity the department is organised in three groups that<br />
focus on the development and adaptation of new tools and<br />
the geometrical data handling (Back Office), use these tools<br />
to investigate the components in the cryostat under the<br />
various configurations (Design Space Analysis) and provide<br />
a complete and collision-free reservation of component and<br />
maintenance space in the torus hall (System Layout). In all<br />
these activities CATIA is implemented as the main CAD<br />
tool. Figure 20 shows the data flow between the different<br />
groups and other subdivisions.<br />
FEA<br />
deformation<br />
data<br />
CATIA PLM<br />
export<br />
System Layout<br />
Space reservation,<br />
Torus hall layout,<br />
Collision check<br />
outside cyrostat<br />
Space reservation,<br />
collision checks,<br />
Proposal of routing<br />
Geometrical<br />
measurements<br />
Back Office<br />
Reverse Engineering<br />
Reverse<br />
Engineering<br />
models<br />
CADDS5<br />
Models<br />
(PLM)<br />
Wendelstein 7-X<br />
Tolerances<br />
Design Space<br />
Analysis<br />
Configuration Control<br />
inside cyrostat<br />
Collision reports,<br />
Information for<br />
reworking, etc.<br />
Figure 20: Information flow within the department Configuration Control<br />
46<br />
5.2.1 Geometrical Data Handling<br />
The main mission of the group Back Office is to handle geometrical<br />
data, i.e. to perform ”reverse engineering” activities,<br />
to assess measurement data and to provide measurement<br />
data and results of calculations of movements or<br />
deformations of components to the whole project. The following<br />
tools have been developed:<br />
• data base tools for usage with CATIA,<br />
• tools to automatically migrate the CADDS5 models into<br />
CATIA readable models,<br />
• tool to generate a mirror image of the PLM CADDS5<br />
assembly tree that combines all components of W7-X at<br />
the time of commencement in CATIA format,<br />
• tools to generate CAD “as-built”, “in-operation nominal”<br />
or “in-operation as-built” models,<br />
• Web-based access to the available data-sets in universal<br />
format,<br />
• Web-based overview of the present status of the reverse<br />
engineering process for all components.<br />
Reverse engineering activities led to as-built models of the<br />
planar and non-planar coils, the central support ring, the<br />
plasma vessel and the outer vessel. By using optimised<br />
meshes for as-built models it was possible to drastically<br />
reduce the time needed for the reverse engineering process<br />
from three to one week. This made it possible to further<br />
refine the configuration checks by providing ”as-built inoperation”<br />
CAD models.<br />
5.2.2 Design Space Analysis<br />
The main mission of this group is to perform configuration<br />
checks of the components in the cryostat to ensure collisionfree<br />
operation. The various configurations considered are<br />
room temperature, cool-down to 4 K, baking of the plasma<br />
vessel and ports at 150 °C, deformation of the coils for 3 T<br />
operation and magnetic configurations standard, low shear,<br />
low iota and high iota. To this purpose the distances of the<br />
considered component to all the neighbouring components<br />
are measured. With the help of CATIA it is possible to automatically<br />
ensure that all near-by components are taken into<br />
account. These distances are evaluated on the basis of the<br />
known or estimated fabrication tolerances, assembly uncertainties,<br />
adjustment regimes and calculated deformations.<br />
Component changes are initiated if collisions are likely.<br />
With the help of the tools made available by the ”back<br />
office” it was possible to increase the accuracy and completeness<br />
of the assessment by replacing the CAD models<br />
with as-built models (if available) or use models that mimic<br />
the calculated operational deformation. The results are documented<br />
in collision reports that then form the basis of design<br />
changes or component changes. In <strong>2007</strong> about 200 collision<br />
reports were issued for e.g. the planar and non-planar coils<br />
of module 5, the central support ring, the port cryo insulation,<br />
and the bus-bars.
5.2.3 Torus Hall Layout<br />
The main mission of the system layout is to provide and document<br />
the space reservation of all the components outside of<br />
the cryostat in the torus hall and adjacent buildings. CATIA<br />
was made the principle tool also for this task. Based on a<br />
discussed and established priority list of the components in<br />
the torus hall the component volume and maintenance space<br />
is systematically being checked and if necessary modified to<br />
meet all requirements: sufficient volume for the component<br />
with some margin for design changes and accessibility for<br />
maintenance and repair. In case of conflicts or if design<br />
changes are required the system layout group organizes and<br />
moderates the required meetings amongst those affected and<br />
takes care that the decisions are properly implemented.<br />
5.3 Design Office<br />
With the foundation of the subdivision ”Design & Configuration”<br />
also the department Design Office (DO) was<br />
restructured. The tasks of the Design Office are developing<br />
design solutions and providing fabrication drawings for<br />
components, supports, and tools for W7-X in close cooperation<br />
with responsible officers in other departments. Additional<br />
tasks are defining and implementing design guidelines<br />
for working with CAD programmes and maintaining a<br />
proper structure of the CAD models in the data base. The<br />
numbers of designers had to be increased in order to cope<br />
with the additional tasks. Those tasks arose when originally<br />
externally designed components were decided to be designed<br />
in-house or when the challenges in finding design solutions<br />
proved more time-consuming than originally estimated. In<br />
order to accomplish these tasks the design office is organized<br />
in four design groups that focus on those areas with<br />
most design activities: structural components in the cryostat,<br />
supply components in the cryostat, components in the plasma<br />
vessel and diagnostic components. Each group has a technical<br />
group leader (or the head of the design office) who<br />
coordinates the work, maintains the design standards and<br />
provides the project with an overall view of what additional<br />
resources are needed to accomplished the still outstanding<br />
design activities. Care is taken that for particularly timecritical<br />
design activities a sufficient number of properly<br />
trained designers is available. The main CAD tool of W7-X<br />
is CADDS5. Good progress has been made to update and<br />
properly position all models and components of W7-X in<br />
the CAD documentation system in the CADDS5 format.<br />
Since in the future the need may arise to use the same CAD<br />
tool as ITER, CATIA V5, a number of projects with well<br />
defined geometrical interfaces (stored in CADDS5) are<br />
being designed in CATIA V5. This also facilitates to gain<br />
experience, create nucleation points for information transfer<br />
and allow external personnel to be hired since the usage of<br />
CATIA V5 is more widespread than CADDS5. Simultaneously<br />
the performance of various CAD storage systems<br />
Wendelstein 7-X<br />
47<br />
for CATIA V5 is being analysed. The group components in<br />
the cryostat focussed on the following tasks: The plasma<br />
vessel CAD models were adjusted to take into account the<br />
latest design changes. The CAD models of the lateral support<br />
elements, that are typically U-shaped structures welded<br />
to the coil housings of adjacent coils on the low field side,<br />
were completed and detailed manufacturing drawings were<br />
provided based on the on-site measurements of the distances<br />
between the coils. The design of the cryostat legs was modified<br />
to incorporate a GFK rather than a stainless steel tube<br />
and the manufacturing drawings were completed. The group<br />
cryostat routing focussed on generating a set of models of<br />
the helium supply lines, supports and cryo shields of the<br />
outer vessel in module 5 of the cryostat that is able to cope<br />
with the increased stresses during the relative movement of<br />
the components during operation. Collision-free design under<br />
all configurations is achieved in close collaboration with<br />
Configuration Control. The group components in the plasma<br />
vessel focussed on completing the detailed design of the<br />
housing of the diamagnetic loops, the model design of the<br />
water supply lines to the wall panels, baffle and targets, the<br />
manufacturing drawings of the wall panels. Various iterations<br />
were necessary in particular for the water line routing after<br />
some significant design changes had to be made as a result<br />
of insufficient installation space. The group diagnostics<br />
focussed on those components that are to be installed earliest<br />
within the assembly schedule. These are the Rogowski coils,<br />
the Mirnov coils, the bolometer, the diamagnetic loops, the<br />
neutral gas manometer and Thomsen scattering.<br />
6 Assembly<br />
In <strong>2007</strong> the preparation of the assembly sites, the assembly<br />
equipment, and extensive assembly trials have been continued.<br />
An additional assembly area (storage and preparation<br />
hall in Lubmin) was rented. Contracts for the design<br />
and the procurement of further complex assembly devices<br />
(assembly bridge, vessel rigs) have been launched. The<br />
mounting stands III and IV were delivered and installed as<br />
planned. The manufacturing of the bus-bars (cooperation<br />
with FZ Jülich) was continued; the first set of conductors<br />
was delivered to Greifswald, the manufacturing pre-requisites<br />
for the mechanical supports of the bus-bars were further<br />
developed. The preparation of plasma-vessel sectors and<br />
coils was continued as planned. Two half-modules are almost<br />
completely assembled in both mounting stand MST I and<br />
MST I b. Expensive assembly trials have been performed to<br />
ensure the mounting accuracy of magnet modules in the<br />
final assembly. Special welding procedures for the LSE<br />
welds with minimised shrinkage were finished. Several new<br />
engineers and craftsmen started their work. The assembly<br />
process-planning, process documentation and work safety<br />
system run furthermore reliably.
6.1 Bus-bar System<br />
The manufacturing of bus-bars continued. The first set of<br />
conductors for the first module was delivered. The manufacturing<br />
of bus-bars runs routinely. The design of mechanical<br />
supports for the bus-bar systems has been further<br />
developed. The associated drawings are partially approved.<br />
Supports had to be redesigned since several clashes with<br />
surrounding components were detected. Assembly tests<br />
with dummy bus-bars were successfully made together<br />
with FZJ. Technicians from INP in Krakow were trained for<br />
the bus-bar installation. The joint-prototype test at the<br />
Efremov <strong>Institut</strong>e was completed. The welding procedure<br />
for the bus-bar joints is finished. Practical installation exercises<br />
have started under real on-site conditions. Construction<br />
works for the current lead joint-prototype were continued.<br />
First practical works with dummies are made. These<br />
works are continued in 2008. The specification for the<br />
wiring and insulation of the quench-detection system was<br />
further developed. The qualification and delivery of insulation<br />
parts was contractually bound. Some difficulties arose<br />
at the manufacturer with respect to the proper handling of<br />
the rather liquid resin.<br />
Figure 21: 1st set of bus bars in the bus bar preparation area<br />
The bus-bar preparation was set-up, all tooling and rigs<br />
were provided and installed. Additional engineers and technicians<br />
from INP in Krakow will be trained and integrated<br />
into the bus-bar assembly team. Again problems with the<br />
aluminium welds at the coil terminals occurred. Small<br />
cracks at production proof samples were detected. The<br />
welding process was refined, however, the limits of feasibility<br />
have already been achieved. In terms of the assembly<br />
schedule more bus-bar works were moved to the preparation<br />
phase; away from the critical path. As a result additional<br />
assembly works on the bus-bar system can now be carried<br />
out without influencing the overall project time plan.<br />
Wendelstein 7-X<br />
48<br />
6.2 Vacuum Technology<br />
The work packages of the vacuum technology group in <strong>2007</strong><br />
were continued as in 2006. Main tasks were: leak detection<br />
on single components and monitoring of leak tests at suppliers<br />
(Tesla, Ensa, BNG) as well as leak and Paschen tests<br />
on coils and on cryo piping of thermal insulation during the<br />
coil preparation and assembly. The works at Tesla were<br />
finalized at the end of <strong>2007</strong>. Local leak tests with diverse<br />
test chambers for superconductor connections and cooling<br />
pipes at room temperature and at 77 K (if technically necessary)<br />
are routinely implemented during assembly. The design<br />
of these test-chambers as well as the qualification of the<br />
tests was further continued. Qualification tests of materials<br />
and devices concerning the suitability in vacuum (outgassing<br />
rates, Paschen stability) were realised in a laboratory.<br />
Little progress was achieved on the specification of the<br />
vacuum systems since it depends on the progress of the layout<br />
in the torus hall.<br />
6.3 W7-X Assembly<br />
The work in the component preparation, especially on coils<br />
and plasma vessel sectors, has been continued as planned.<br />
Components for the second module are being prepared. The<br />
works are running routinely. The scope of scanning works<br />
on these components was considerably extended. As a result<br />
additional external resources had to be hired. Additional<br />
storage capacity for prepared components outside the institute<br />
was refurbished and put into operation.<br />
Figure 22: PV sectors during the test assembly – rigs are sliding on air<br />
cushions<br />
Additional staff was hired to cope timely with the expanded<br />
preparation works. There were, however, hardly any technological<br />
changes in the coil preparation. Therefore, one can<br />
consider the qualification of the coil preparation as completed<br />
from today’s point of view. With respect to the preparation
of plasma vessels difficulties arose. The preparation of three<br />
dimensionally bent cooling tubes turned out to be quite timeconsuming<br />
due to very restricted tolerances. Special procedures<br />
and tooling were developed to cope with the situation.<br />
Concept works have started to establish an effective procedure<br />
for the closure of the openings in the plasma vessel.<br />
The openings are caused by the omitted 45 ports. The preparation<br />
work on the ports was continued in an external hall.<br />
The scope of incoming inspections at ports had to be considerably<br />
extended since many unexpected contour and<br />
position deviations were found. A special soldering-process<br />
was developed to connect ports with copper foil. This shall<br />
guarantee the demanded cooling qualities of ports.<br />
Figure 23: Incoming inspection of ports<br />
The two first half modules are built up in the pre-assembly<br />
in the mounting stand Ia and Ib as planned. It is expected<br />
that they are ready at the beginning of March. The assembly<br />
area for the subsequent connecting into modules is already<br />
prepared. The assembly of segments of the central support<br />
ring ran as planned. No severe technical problems occurred.<br />
The tightening of bolts and SUPERBOLT nuts worked without<br />
problems. The welding of lateral support elements was<br />
materialised with the expected high accuracy. Many lessons<br />
were learned within the last months in which the assembly<br />
speedily went forward. Extended working times in two shifts<br />
and additional personnel were used to meet the challenging<br />
assembly schedule. The cooperation of the different departments<br />
at the assembly worked exemplarily. Corrective actions<br />
for deviations in quality were immediately decided with the<br />
help of the configuration control board. The next main step<br />
is the start of the module assembly within the pre-assembly<br />
phase. Particularly the joining of adjacent central support<br />
ring segments requires further qualification. In that context,<br />
practical tests with reaming tools have been performed in<br />
<strong>2007</strong>. They will be continued within the next months.<br />
Wendelstein 7-X<br />
49<br />
For the second module the preparation of separation planes<br />
of plasma vessel sectors was jointly made with MAN DWE.<br />
The assembly equipment and the accompanying processes<br />
worked as planned. A special challenge in that phase will be<br />
the assembly start of the bus-bar system, the helium piping<br />
and the module instrumentation.<br />
Figure 24: Trial threading with M76 bolt<br />
The set-up of mounting stands III and IV in the torus hall<br />
were successfully completed in <strong>2007</strong>. Tests showed that the<br />
systems work as designed and without any inadmissible<br />
deviations. A very complex alignment test was made by the<br />
use of MST IV simulating the final adjustment of 100 t<br />
modules within an adjusting range of +/-5 mm in all three<br />
directions. The test preparation was extensive and lasted<br />
about half a year. The test equipment was timely delivered<br />
by industry. At the end it was shown that the alignment<br />
worked as planned with accuracy far below 1 mm, i.e. much<br />
better than planned. Problems with the electrical insulation<br />
of the machine base (grounding) were successfully solved.<br />
Works were continued for the assembly conception of outer<br />
vessels. It turned out, that the needed assembly equipment<br />
will be much more complex than expected. First parts of<br />
that equipment were designed and ordered in <strong>2007</strong>. The<br />
design works were assisted by colleagues from PAS in<br />
Krakau. This work is time-critical and is continued with<br />
additional resources in the year 2008. It also turned out that<br />
the thermal insulation of the outer vessel shells is much<br />
more time-consuming than planned and that it requires<br />
much more space than originally available. It became necessary<br />
to hire an additional hall – large enough to store 8 to<br />
10 shells and to allocate the workplace for the insulation<br />
works. A hall was found at a distance of 30 km and the renovation<br />
work has already started. It is planned to start the<br />
preparation works at the first outer vessel shells in the early<br />
summer of 2008. The ramps and the bridge for the port
installation were ordered in industry. As usual, the detailed<br />
manufacturing design was much more challenging than<br />
expected but the procurement of these devices is presently<br />
within schedule. The first delivery of these devices is<br />
expected for the middle of 2008. The installation procedure<br />
for ports was further refined in <strong>2007</strong>. Particularly for special<br />
(non standard) ports these works have to be continued in<br />
2008. In addition welding tests were started to develop first<br />
procedures for the joining of port to the vessels. These tests<br />
are continued in 2008.<br />
Figure 25: Trial alignment with 100 t-dummy load<br />
The cooperation with the colleagues from <strong>IPP</strong> Garching in<br />
the field of conceptual planning of the assembly of the KiP<br />
has been continued in <strong>2007</strong>. First assembly equipment for<br />
in-vessel components was designed, provided and tested in<br />
the assembly area. Systematic investigations for interactions<br />
of the different tolerances and deviations on the components<br />
of the cryostat during manufacturing and assembly were<br />
carried out. With the periphery, the work on cryo instrumentation<br />
has been further continued. Due to clashes of the helium-piping<br />
with other components the routing of the cryo<br />
instrumentation was redone. A simplified system of holders<br />
and mechanical supports was developed to speed up the<br />
installation of the instrumentation. The design for the first<br />
Wendelstein 7-X<br />
50<br />
module is available. First components have already been<br />
qualified. Installation works of the extension of the low<br />
voltage power supply system have started. The work runs as<br />
planned, the earthwork foundation is completed. Detailed<br />
planning of the concept of the grounding area in the torus<br />
hall and diagnostic was continued. The high rack for the<br />
control unit was mounted as planned and without any<br />
inadmissible deviations. The first construction stage of the<br />
cooling system was started in <strong>2007</strong>. These works are ongoing<br />
as planned. The assembly control and planning work<br />
reliably as before. Additional resources have been allocated<br />
to cope with the increased work load. The weekly and<br />
4-weekly plans identify necessary handover dates for components<br />
for assembly so that the other subdivisions and<br />
departments are able to provide the necessary information<br />
and make appropriate decisions. The preparation of the<br />
assembly documentation (QAAP, work and test instructions)<br />
is ongoing without any severe problems. In 2008 the daily<br />
planning will be refined to improve the utilisation of resources.<br />
A system was implemented to monitor the consumption<br />
of resources. That system will be further completed in<br />
2008. Quality deviations are reliably recorded and monitored.<br />
The fast preparation of effective corrective actions by<br />
the causer of a quality deviation has to be improved. The<br />
nomination of a Configuration Control Board improved the<br />
effectiveness and speed of decisions which are caused by<br />
quality deviations. The complete assembly schedule and the<br />
plan of resources were again extensively updated and optimised<br />
in detail. The effect of the delayed component delivery<br />
and the additional assembly work were considered in updated<br />
milestones. Contingencies were included to cope with<br />
yet unknown assembly technologies. Additional personnel<br />
recourses for assembly have been included (metrology,<br />
mechanics). Three additional responsible officers (final<br />
assembly supervision, planning, and KiP) took up their<br />
employment. More external staff was included to man the<br />
two-shift system and the extended working times in the<br />
assembly. Additional engineering staff started work for the<br />
procurement of the extensive assembly devices of the outer<br />
vessel. A cooperation with engineers and technicians of the<br />
Polish Academy of Sciences has started. A detailed planning<br />
for an accelerated assembly schedule was carried out. The<br />
increase of the working time per week, a reduction of the<br />
amount of components to be assembled as well as the availability<br />
of additional assembly equipment are the essential<br />
changes in that updated plan. The expected date of the start<br />
of commissioning of W7-X is now in mid 2014. Altogether,<br />
assembly has reached the planned progress in <strong>2007</strong>. Several<br />
new assembly technologies were qualified and successfully<br />
tested. The assembly technologies for the preparation of<br />
coils and plasma vessels as well as for the mechanical preassembly<br />
of modules were defined. Particularly in the second<br />
half of <strong>2007</strong> the device assembly ran continuously and
speedily as planned. Additional resources for engineering<br />
tasks and additional technicians for assembly works were<br />
hired to cope with the challenging schedule. Additional<br />
storage and preparation space was procured and refurbished.<br />
New work packages for the technology development of the<br />
final assembly were launched. The purchasing of the peripheral<br />
hall equipment (cooling circuit, electronics, vacuum,<br />
etc) occurred as planned. In <strong>2007</strong> the weekly working coordination<br />
was complemented by daily co-ordinations. Up<br />
to now, there are approximately ten companies and partnerinstitutes<br />
which provide skilled and well-trained technicians<br />
and engineers for the realisation of the assembly work on<br />
W7-X. That cooperation works well. In 2008 further companies<br />
shall be qualified in order to meet the increase of personnel<br />
required by the subdivision Assembly.<br />
Figure 26: The almost completed half modules Ia and Ib<br />
7 Diagnostics<br />
7.1 Overview<br />
The work concentrates on the ”start-up diagnostics” set<br />
necessary for safe operation and control of the machine and<br />
those diagnostics adapted to and being indispensable during<br />
the initial operation phases of the experiment. Time, financial<br />
and manpower planning is adjusted to the agreed modified<br />
time schedules of the W7-X assembly. The diagnostics<br />
project/department is divided into nine expert groups and<br />
groups on technical coordination, documentation and control.<br />
A temporary working group within the project covers<br />
R&D on the development of heat-resistant plasma facing<br />
optical components.<br />
7.2 <strong>Report</strong>s of Expert Groups<br />
The following sections briefly summarise the main activities<br />
within the expert groups of the project. Due to assigned<br />
Wendelstein 7-X<br />
51<br />
priorities there were no activities in <strong>2007</strong> in the subgroups<br />
on fluctuations, fusion products and heavy ion beam probe<br />
and fast particles.<br />
7.2.1 Edge and Divertor Diagnostics<br />
The activities regarding the divertor thermography system<br />
focused on basic investigations of the temperature enhancement<br />
and its temporal evolution at surface heat loading of<br />
contaminated CFC-surfaces. The measured surface temperature<br />
excursions have been compared with values of analytic<br />
and numerical solutions of the heat diffusion equation taking<br />
into account a surface region with low thermal conductivity<br />
or poor thermal contact to the underlying substrate material.<br />
Collisions of the pop-up arrays and its drives with divertor<br />
structures have been eliminated and the complete routing<br />
for all media (electricity, pressurised air) of one pop-up<br />
array was carried out including mounting and welding<br />
aspects. The set of manufacturing drawings was completed<br />
further. Following the idea of exploiting the same probe<br />
array for the Test Divertor Unit (TDU) and the High Heat<br />
flux Divertor (HHD) and as a consequence of the different<br />
bending of the target elements under thermal load a completely<br />
new concept for the pop-up Langmuir probe arrays is<br />
envisioned. This should allow for an independent motion of<br />
the individual probe together with a local placement with<br />
respect to the target surface. An attempt will be made to<br />
move over from a pneumatic to an electric drive to get rid of<br />
the pressurised air. First manufacturing drawings of manometer<br />
cannulae are produced and three flanges for prototypes<br />
are manufactured and completed with feedthroughs<br />
and welded signal cables. Two of those passed the vacuum<br />
leakage tests. A final design of the screens against electromagnetic<br />
disturbances was completed. The semi-finished<br />
parts for the cannulae have been selected and the manufacturing<br />
drawings were adapted to this selection. As the result<br />
of several tests of the manometer electronics we decided for<br />
one type of power supply for the manometer heating and<br />
ordered those supplies. Several measures to reduce the<br />
observed noise in the manometer signals are being discussed<br />
and investigated. This activity is still ongoing.<br />
7.2.2 Microwave Diagnostics<br />
For the first experimental campaign of W7-X the group<br />
prepares the multi-channel ECE radiometer, a basic version<br />
of the multi-channel Mid-Infrared Interferometer dedicated<br />
to cross calibration of the Thomson scattering and density<br />
feedback control and a single Interfero-Polarimeter channel<br />
to ensure redundancy of the latter. Preparative work<br />
for Reflectometry is also conducted. According to schedule<br />
the main design activities were related to in-vessel components.<br />
A basic design for interferometry retro-reflectors<br />
which have to be integrated into the first-wall heat shield<br />
was developed together with the Dutch company TNO.
FE calculations show that the degradation of the optical<br />
specifications resulting from high heat loading during 30 min<br />
discharges can be minimised by constructive measures. A<br />
PhD thesis on the optimization of sightline geometry of the<br />
multi-channel interferometer was finished. In the laboratory<br />
the optic design of the prototype two-frequency CO 2 -CO<br />
laser interferometer has been improved. On focus were<br />
mode purity, the development of a single detector design<br />
and the minimization of crosstalk. The cooperation with<br />
CIEMAT (Madrid) where a CO 2 -YAG system is operated at<br />
the TJ-II stellarator continued. A two frequency arrangement<br />
with wavelength combination of 10 μm and 5 μm is necessary<br />
to cope with vibrations and thermal drifts of the optical<br />
path length during the discharge. An interesting alternative<br />
for steady state devices could be dispersion interferometry<br />
where the second required wavelength is obtained by frequency<br />
doubling in non-linear crystals. A prototype system<br />
is being operated at the TEXTOR tokamak. Its steady state<br />
capability and extension to a multi-channel system is being<br />
investigated, finally aiming at a quantitative comparison of<br />
both alternatives. Preliminary studies for electron density<br />
measurements by Polarimetry in the complex magnetic geometry<br />
of W7-X were conducted in cooperation with the<br />
Akademia Morska, Szczecin, Poland and the Technical<br />
University of Szczecin. Main topics were the minimization<br />
of spurious polarization changes introduced by the unavoidable<br />
retroreflector behind the plasma. In the framework of<br />
the European Fusion Training Scheme (EFTS) a training<br />
program Microwave Diagnostic Engineering for ITER<br />
(MDEI) has been proposed together with IST Lisboa, CEA<br />
Cadarache, and CIEMAT Madrid. Approval was in July. The<br />
trainee program started at <strong>IPP</strong> Greifswald in November with<br />
test measurements on the W7-X multi-channel ECE system<br />
and design work on ECE in-vessel viewing optics. For<br />
Reflectometry preparatory work on in-vessel components<br />
and transmission lines is continued to ensure the availability<br />
of this diagnostic for the characterisation of edge density<br />
profiles in divertor relevant W7-X scenarii. As a basic component<br />
of the W7-X Diagnostics Project, the Microwave<br />
Stray Radiation Launch facility (MISTRAL) has been installed<br />
at <strong>IPP</strong> Greifswald. Starting from March 2008 diagnostic-<br />
and other in-vessel components will be tested in this<br />
test facility in the environment of continuous isotropic<br />
140 GHz radiation as expected also in certain ECRH-heated<br />
scenarios.<br />
7.2.3 Charge Exchange Diagnostics<br />
The group is developing the Russian Diagnostic beam<br />
(RuDI-X) needed for active CXRS and CX-NPA measurements<br />
in cooperation with FZ-Jülich and the Budker-<br />
<strong>Institut</strong>e of Nuclear Physics (BINP) Novosibirsk. The latter<br />
has continued the construction of the HV power supply<br />
(60 kV, 10 A). The tests of RF and ion arc sources at the<br />
Wendelstein 7-X<br />
52<br />
diagnostic beam at TEXTOR are finished, favouring the<br />
RF source for RuDI-X. Infrastructure work (cooling water<br />
supply, power supply, collision studies, etc) for the installation<br />
of the diagnostic beam was continued. The high voltage<br />
transformer for the injector has already been installed in the<br />
operating lab. It has been decided to use a closed circuit<br />
cryogenic pump systems, directly connected up to the neutraliser<br />
chamber, rather than a LHe bath system. <strong>Report</strong>s on<br />
the status of RuDI-X were presented by participants from<br />
BINP, FZJ and <strong>IPP</strong>-MPG in a meeting in Greifswald from<br />
18.-20.08.<strong>2007</strong>. For CX-NPA measurements a set-up of one<br />
Compact Neutral Particle Analyser (CNPA), two ACORD-24<br />
and one ACORD-22 analyser is foreseen. The CNPA has<br />
been tested on MAST at the Culham Science Centre showing<br />
results which are in good agreement with results of the<br />
Princeton analyser. The IOFFE <strong>Institut</strong>e St. Petersburg has<br />
started with the conversion of a 10 channel analyser from<br />
W7-AS into an ACORD-24 analyser. The completion of this<br />
analyser upgrade is planned for September 2008. It will be<br />
used in the calibration laboratory for the NPAs which is<br />
presently being set-up at <strong>IPP</strong> Greifswald.<br />
7.2.4 Spectroscopy<br />
The test operation of the high-efficiency XUV overview<br />
spectrometer system (HEXOS) installed on TEXTOR (FZ<br />
Jülich) has been continued successfully. VUV/XUV spectra<br />
were recorded with high time resolution (1 ms) over the full<br />
duration of almost all TEXTOR discharges in <strong>2007</strong>, thereby<br />
demonstrating a full coverage of all prominent impurity<br />
lines with high availability (>98 %) and good spectral resolution.<br />
An intensity calibration of the HEXOS spectrometer<br />
channels was performed and a variety of transient impurity<br />
transport experiments (fast Argon puffing) were conducted.<br />
The hardware assembly of the remote control system is<br />
completed and the programming is in progress. The cooperation<br />
between <strong>IPP</strong> and the University Opole (Poland) concerning<br />
the development of a C/O monitor diagnostic for<br />
W7-X has officially been started and a work break down<br />
schedule agreed on. The basic design was fixed and various<br />
options for detectors are presently under discussion. For<br />
selection and test of appropriate detectors, crystals and calibration<br />
sources the W7-AS crystal spectrometer was transferred<br />
to and reassembled in Opole. For achieving sufficient<br />
bolometer sightline coverage of the plasma cross section for<br />
tomographic inversion, the observation gap in the baffle<br />
structure for the divertor bolometer in front of the AEJ40<br />
port has been enlarged and the diagnostic design for the<br />
enlarged cut-out been finished. For the bulk plasma bolometer<br />
system in the triangular plane the design of the sightlines<br />
of the AEU30- and AEV30-camera has been completed.<br />
The camera in the AEU30 port possesses 32 up/down<br />
symmetric channels, collimated by one slit-aperture. The<br />
camera in the AEV30 port contains two detector lines of
20 channels each which are collimated by two separate slitapertures<br />
in order to achieving the required wide viewing<br />
angle view. A first design of the water cooled aperture plate<br />
and detector holder has been completed. FE calculations<br />
(ANSYS) of these designs are presently being performed<br />
to evaluate the temperature of the camera components for<br />
W7-X steady state operation conditions (~50 kW/m 2 ). A<br />
study of the neutral pressure sensitivity of the metal foil<br />
detectors has shown that blind-channels need to be integrated<br />
into the design of the bolometer cameras to monitor this<br />
effect. The detailed design of the video diagnostics – which<br />
is being developed by KFKI-RMKI Budapest – was finished<br />
in <strong>2007</strong>. For the video observation the 10 equivalent<br />
tangential AEQ-ports of the W7-X vacuum vessel will be<br />
used giving nearly full coverage of the entire plasma vessel.<br />
In the elaborated design the Sensor Module (SM) of the<br />
Event Detection Intelligent Camera (EDICAM) is located at<br />
the plasma end of the ports. The mechanics that transports<br />
and docks the camera capsule – containing the SM to the<br />
front window was manufactured and its mechanical and<br />
thermal tests will be completed in 2008. Also the design of<br />
the diagnostic front end, consisting of an air – vacuum<br />
window, a small shutter and a water cooled plasma facing<br />
front plate with a pinhole for plasma observation has been<br />
completed by <strong>IPP</strong> Greifswald. The manufacturing of the<br />
prototype is still ongoing. Radiation resistance test had been<br />
performed on the first version of the Sensor Module. The<br />
current version of the SM consists of only the essential electronics<br />
in order to allow testing the performance of the<br />
CMOS sensor itself, without the possible influence from a<br />
more complex electronics. The SM was irradiated at different<br />
gamma (between 0.1 Gy/h and 5 Gy/h) and fast neutron<br />
(between 0.7 Gy/h and 1.4 Gy/h) dose rates in fission<br />
research reactors. The evaluation of the images obtained<br />
during the gamma irradiation test shows no enduring damage<br />
on the CMOS sensor. Gammas cause only short time<br />
flashing of the effected pixels. During the neutron irradiation<br />
test the SM absorbed about 60 Gy total dose (about the<br />
quadruple of the expected upper limit of the annual dose at<br />
W7-X) revealing a clear increase of the dark current of the<br />
individual pixels with increasing accumulated dose, but it<br />
still remained functional. The development of the EDICAM<br />
Image Processing and Controlling Unit (IPCU) and 10 Gbit<br />
fibre link connecting the SM to the IPCU advances according<br />
to the plans. The hardware kit for the IPCU (FPGA development<br />
board with PCI express PC connector, ALTERA)<br />
was purchased. The 10 Gbit fibre link is expected to be ready<br />
in 2008.<br />
7.2.5 Thomson Scattering<br />
The design of a polychromator prototype for analysing the<br />
scattered light was continued and successfully tested at<br />
ASDEX-Upgrade. A water cooled shutter was designed, to<br />
Wendelstein 7-X<br />
53<br />
protect the vacuum window in front of the observation port.<br />
A design study for the observation optics has been performed<br />
with the optical design program ZEMAX.<br />
7.2.6 Soft X-Ray and Magnetic Diagnostics<br />
The design for the integration of the in-vessel X-ray tomography<br />
camera system (XMCTS) beneath the heat protection<br />
roof (designed by KiP) has been finalised. The camera<br />
design including the cooling is completed and finite element<br />
calculations were performed proving the effectiveness of the<br />
cooling with respect to the expected heat fluxes. Several<br />
components for the XMCTS are being manufactured for<br />
prototype testing. Notably, the vacuum feed-through connectors<br />
between the photo diode array and the electronic<br />
box have been designed and manufactured by the company<br />
Schott. The shutter prototype (protecting the photo diodes<br />
during glow discharges and allowing for offset drift correction<br />
during long discharges) was tested. Its mechanical<br />
design is based on a pressurised manometer tube spring<br />
attached to a lid. It was demonstrated that the shutter is<br />
capable of more than 100,000 cycles under vacuum conditions<br />
with additional heating cycles. The robustness of the<br />
design is therefore sufficient, but small improvements are to<br />
be considered for optimal operation in the W7-X vessel. The<br />
continuation of the work on the preamplifiers was very difficult<br />
throughout the year due to the lack of manpower in the<br />
Greifswald electronics department. The cross-talk problem<br />
between channels has been overcome to a large extent. One<br />
of the main tasks in 2008 will be the test of a preamplifier<br />
board fitted into the vacuum-tight electronic box. Further<br />
major tasks in 2008 are the in-vessel cable routing and the<br />
assembly of a prototype camera. The legacy code for the<br />
tomographic inversion of W7-AS SX-ray data is being ported<br />
from a specific AIX/W7-AS environment to a general Linux<br />
version, which will be advantageous with respect to the<br />
processing speed and portability. The code was simplified,<br />
generalized and optimised and converted to a more consistent<br />
and object-oriented design. The long discharge<br />
lengths of W7-X pose a severe challenge to the data analysis<br />
task. The amount of data from the XMCTS system in continuous<br />
acquisition for a 30 min discharge sums up to about<br />
500 GBytes. A method for an online method giving information<br />
on the plasma shape and possibly mode onsets on a<br />
human time scale is desirable. One approach to this challenge<br />
involves the application of neural networks, which are<br />
real time capable after a time-consuming training phase.<br />
This work was done in collaboration with IST and <strong>IPP</strong><br />
Garching. First results were presented on the Plasma <strong>2007</strong><br />
conference. The collaboration contract with the <strong>IPP</strong>LM in<br />
Warsaw on X-ray pulse height analysis and on an electron<br />
temperature monitor system based on the filter foil method<br />
has to be extended. The main focus in <strong>2007</strong> was on the layout<br />
of the filter system and on suitable data analysis algorithms.
A major task in 2008 will be the choice and procurement of<br />
a detector for X-ray pulse height analysis which will be<br />
tested at <strong>IPP</strong>LM. The magnetic diagnostics has been further<br />
constructed and manufacturing processes have been qualified.<br />
The first Rogowski coil in module 1 has been successfully<br />
tested. The tests have been performed by using a cable<br />
that is fed through the small sector of the plasma vessel, on<br />
which the coil has been installed. This cable represents a<br />
localised plasma current and has been supplied with a current<br />
of 200 Amps. The induced voltage has then been integrated<br />
using the original prototype digital integrator running<br />
under Linux. The results are very promising with respect to<br />
integrator drift values in the envisaged steady state discharges.<br />
The measured drifts are the order of 1 Amp. per<br />
minute discharge duration. The design of the diamagnetic<br />
loops has almost been completed and the concept of the loop<br />
fixation has been worked out. The manufacturing of the<br />
100 pin connector has been qualified for connecting the<br />
Kapton insulated ribbon cable in order to form the electrical<br />
loop of at maximum 100 windings. Additionally, a second<br />
small prototype loop has been built and is ready for dedicated<br />
ECRH stray radiation tests with several different<br />
microwave screening materials. The installation of the saddle<br />
loops has been continued, that is module 1 has been fully<br />
equipped with all 8 loops. Furthermore, a first routing of<br />
saddle loop signal cables in the warm region of the cryostat<br />
along the cooling pipes of the plasma vessel has been<br />
realised in module 5. The cable routing of all magnetic diagnostics<br />
is under revision due to the cancellation of a number<br />
of ports. One complete system of 10 identical ports is omitted<br />
entirely, which had originally been assigned for cable<br />
feed through. Thus, re-routing has become necessary and<br />
substitute cable paths are currently under investigation.<br />
7.2.7 Diagnostics Software<br />
7.2.7.1 Physics Data Repositories<br />
The development of data repositories for preparation of<br />
W7-X was continued. The “Reference Database” was filled<br />
with predictive calculations from neoclassical transport<br />
simulations. These simulations cover ECRH and NBI density<br />
and power scans for different magnetic configurations.<br />
The parameter range is continuously extended. The structure<br />
and general policy of the international Stellarator/<br />
Heliotron profile database was discussed and agreed with<br />
the collaborators.<br />
7.2.7.2 Software Development Infrastructure<br />
Central software repositories were provided for routine<br />
work in the W7-X Project and for physics codes. A WIKI<br />
system – also hosting the Reference Database – was set up<br />
and is employed for diagnostics development communication<br />
(in cooperation with RZG). A reference server for<br />
integration purposes was set up. Software standards were<br />
Wendelstein 7-X<br />
54<br />
assessed in order to develop a software quality management<br />
(in collaboration with W7-X QM).<br />
7.2.7.3 Integrated Data Analysis and Diagnostics Design<br />
Efforts on Integrated Data Analysis were continued in collaboration<br />
with ASDEX Upgrade. A simulation code for<br />
video cameras was developed. An XML-schema for the<br />
parameter description in simulation of the tomography was<br />
developed. The case study for the interferometer design<br />
were finished and documented. The software support of the<br />
design of the polychromator system was finished and documented.<br />
The analysis of spectroscopic data was continued<br />
and first results for the reconstruction of electron energy<br />
distribution functions were obtained. (Cooperations with<br />
W7-X Diagnostics and ASDEX Upgrade).<br />
7.2.7.4 International Stellarator/Heliotron Confinement and<br />
Profile Database<br />
Within an international collaboration (IEA implementing<br />
agreement) the International Stellarator/Heliotron Confinement<br />
and Profile Database was continued and extended.<br />
Comparative Studies on impurity transport, divertor physics,<br />
energy confinement, neoclassical effects were performed<br />
and documented (NIFS, CIEMAT, University of Kyoto,<br />
ANU, University of Wisconsin, PPPL, University of Stuttgart).<br />
7.2.8 Technical Coordination<br />
The assembly of the first outer Rogowski-coil has been<br />
completed by making the electrical contacts, measuring the<br />
induction and mounting a temporary shield. The saddle coils<br />
on the two larger half sectors of the half modules 10 and 11<br />
were assembled in time before the assembly of the thermal<br />
insulation. To denominate the diagnostics according to the<br />
prescribed KKS-system, the aggregate key was extended.<br />
The requirements on the materials used for the video cameras<br />
were specified and relayed to the cooperation partner, the<br />
KFKI-RMKI institute in Hungary. The signal exchange<br />
between the EDICAM camera and the W7-X control and<br />
data acquisition system was discussed and the further course<br />
of action agreed on. A working group was initiated to deal<br />
with the requirements on weld seams in the diagnostics.<br />
Layouts for the west and for the south part of the first basement<br />
of the torus hall were drafted that now include all<br />
necessary support structures of the components that are<br />
positioned above these areas. The data on the fire load of the<br />
diagnostics in the torus hall have been collected.<br />
7.3. Collaborations<br />
The diagnostics are being developed in close collaboration<br />
with FZ-Jülich. In particular in case of the HEXOS VUV<br />
spectrometer and the development of the diagnostic neutral<br />
beam FZ-J is heading the projects. The Budker <strong>Institut</strong>e in<br />
Novosibirsk, Russia, is developing and constructing the
diagnostic neutral beam injection system, KFKI/RMKI in<br />
Budapest, Hungary, is developing and constructing the<br />
video diagnostic systems for W7-X, <strong>IPP</strong>LM, Warsaw is<br />
developing a neutron activation system and performing<br />
MCP calculations for W7-X, the university of Opole (Poland)<br />
is preparing a C/O monitor diagnostic and the Akademia<br />
Morska, Szczechin and the Szczechin University of Technology<br />
are investigating the sightline of the Interfero-<br />
Polarimeter and different microwave based polarimeter and<br />
interferometer methods, CIEMAT investigates potential and<br />
components for CO 2 -Intefererometry, IST participates in<br />
developing fast tomographic inversion methods (P. Carvalho<br />
4 Months stay in Greifswald) and is developing ADC/DAQ<br />
stations being linked to XDV, PTB, Braunschweig is performing<br />
preparatory work for a contract on the development<br />
of a Neutron-Counter System for W7-X and IOFFE <strong>Institut</strong>e<br />
St. Petersburg, the Culham Science Centre (UKAEA) and<br />
CIEMAT in Madrid are collaborating in the field of CX-<br />
Neutral Particle Analysis.<br />
8 Heating<br />
8.1 Project Microwave Heating for W7-X (PMW)<br />
The Electron Cyclotron Resonance Heating (ECRH) system<br />
for W7-X is being developed and built by FZ Karlsruhe<br />
(FZK) as a joint project with <strong>IPP</strong> and IPF Stuttgart. The<br />
“Project Microwave Heating for W7-X” (PMW) coordinates<br />
all engineering and scientific activities in the collaborating<br />
laboratories and in industry and is responsible for the entire<br />
ECRH system for W7-X. ECRH is designed for a microwave<br />
power of 10 MW in continuous wave (CW) operation<br />
(30 min) at 140 GHz, which is resonant with the W7-X magnetic<br />
field of 2.5 T. It will consist of ten Gyrotrons with<br />
1 MW power each, a low loss quasi-optical transmission<br />
line and a versatile in-vessel launching system. It was<br />
shown recently, that the gyrotrons operate also at 103.6 GHz<br />
with about half the output power, which would extend the<br />
flexibility of the ECRH significantly. PMW is strongly<br />
involved in advanced and ITER related R&D activities.<br />
8.1.1 The W7-X Gyrotrons (FZK)<br />
The TED-Gyrotrons SNo. 2 and 3 failed to meet the specified<br />
output power in the acceptance tests and were sent back<br />
to TED for inspection. Strong defects in the electron beam<br />
tunnel between gun and cavity were identified, which were<br />
believed to be the reason for the measured power limitation.<br />
TED presented a failure analysis indicating a fabrication<br />
problem during brazing of these parts. An improved procedure<br />
for the manufacture was qualified and the critical parts<br />
were replaced in both, the SNo. 2 and 3 Gyrotrons. The<br />
SNo. 2 (repair) Gyrotron was delivered to FZK by end of<br />
July, where an output power of 0.55 MW/30 min and<br />
0.85 MW/3 min were achieved, respectively. Then a water<br />
Wendelstein 7-X<br />
55<br />
leak opened at the cw dummy load in the test stand, which<br />
prevented further long pulse testing. The gyrotron was<br />
shipped to <strong>IPP</strong>, where the FAT will be continued in January.<br />
As short-pulse testing is still possible in the FZK test stand,<br />
the Gyrotron SNo. 3 (repair) was installed by fall of the year<br />
and short pulse testing has started. The Gyrotron SNo. 4 was<br />
also equipped with the improved beam tunnel and passed<br />
the Factory Acceptance Test (FAT) at FZK successfully<br />
(0.5 MW/30 min, 0.91 MW/3 min). The gyrotron was then<br />
transferred to <strong>IPP</strong>-HGW for the site acceptance test (30 min),<br />
where 0.83 MW were achieved for 8 min, as the tests had to<br />
be stopped, because the rf-beam parameters showed some<br />
deterioration after a cooling failure. The gyrotron was<br />
shipped to TED for inspection. The W7-X gyrotrons are<br />
optimized for single frequency operation at 140 GHz. As the<br />
gyrotron diamond window has a resonant thickness of 4λ/2<br />
at 140 GHz, it is, however, also transparent at 105 GHz corresponding<br />
to 3λ/2. Two modes, the TE 21,6 (103.6 GHz) and<br />
TE 22,6 (106.3 GHz) exist in the vicinity of the desired frequency.<br />
Both modes could be exited by tuning the resonant<br />
magnetic field and adjusting the operation parameters<br />
(I beam =40 A and U acc =62 kV). We have focused on the<br />
TE 21,6 -mode operation, because the output beam was almost<br />
perfectly centered on the output window, whereas the beam<br />
from the TE 22,6 -mode was located somewhat off centre. As<br />
seen from figure 27 (above), a maximum output power of<br />
about 0.52 MW was achieved without collector voltage<br />
depression corresponding to an efficiency η=21 %, which is<br />
slightly higher than the theoretical prediction of η =17 %.<br />
The output power drops with increasing depression voltage<br />
while the efficiency increases from 21 % to 27 %. The corresponding<br />
collector loading at 0 and 8 kV depression voltage<br />
is 1.9 and 1.7 MW, respectively, which is incompatible<br />
with the collector-loading limit of 1.3 MW. Thus only operation<br />
with reduced beam current around 34 A (about 400 kW)<br />
can be handled safely by the collector. The rf-beam was<br />
transmitted through 7 mirrors of the quasi-optical transmission<br />
line into a calorimetric cw-load. Transmission losses<br />
of about 20 kW were measured, which compares well with<br />
the transmission loss fraction at 0.9 MW, 140 GHz operation.<br />
It is worth noting, that both the beam matching mirrors<br />
as well as the set of polarizers can be used without modification.<br />
The larger beam size at the lower frequency is expected<br />
to introduce slightly higher losses as compared to<br />
the nominal frequency. On the other hand the atmospheric<br />
absorption is somewhat lower.<br />
Assuming, that all series gyrotrons behave similar to the<br />
Prototype, ECRH for W7-X will be operated as a two-frequency<br />
system. As sketched in figure 27 the operation range<br />
of experiments can then be extended towards different resonant<br />
magnetic field of 1.86 T (X2 and O2 mode) and 1.25 T<br />
(X3 mode), respectively. Once plasma start-up could be<br />
achieved with X3-mode, which is not clear yet, operation at
1.25 T is of particular interest, because ECRH could then<br />
provide a target plasma for NBI for high-ß physics studies,<br />
which is most promising at low magnetic field.<br />
800<br />
600<br />
400<br />
200<br />
TED-Prototype<br />
RF-Power vs. Collector depression (103.8 GHz)<br />
0<br />
-4,0 0,0 4,0 8,0 12,0 16,0 20,0<br />
Body-Voltage (kV)<br />
3<br />
2,5<br />
2<br />
1,5<br />
1<br />
0,5<br />
0<br />
I beam=40 A<br />
104 GHz<br />
140 GHz<br />
X3<br />
I beam=40 A<br />
I beam=32-34 A<br />
Accel.Voltage: 61.6 - 62.0 kV<br />
Beam Current: 32 -40 A<br />
Figure 27: Above: Output power in the TE 21,6 mode (103.6 GHz) as a<br />
function of the depression voltage at constant acceleration voltage<br />
(UACC=62 KV). Below: Cut-off density vs. resonant magnetic field for<br />
different modes at both frequencies.<br />
8.1.2 High-voltage system for Gyrotron power control and<br />
protection (IPF)<br />
The HV-control system for the W7-X Gyrotrons consists of<br />
a high-voltage modulator unit, which provides and controls<br />
the Gyrotron body voltage, and a crowbar unit with thyratronswitch<br />
and integrated heater supply for the Gyrotron cathode.<br />
The modulator is capable of delivering modulated body<br />
voltages up to 30 kV at a rise time of up to 600 V/ms. The<br />
HV system is remote controlled via optical fiber links by a<br />
special control unit in the master control centre. The fabrication<br />
of all units by IPF Stuttgart was finished and the installation<br />
at <strong>IPP</strong>-Greifswald was completed in <strong>2007</strong> by adding<br />
the three remaining modules. Nine out of the ten modules<br />
passed the acceptance test, the SAT of the last module is<br />
scheduled for beginning of 2008. The integration of the<br />
X3<br />
0 0,5 1 1,5 2 2,5 3<br />
Magnetic field [T]<br />
O2<br />
X2<br />
O2<br />
X2<br />
Wendelstein 7-X<br />
56<br />
many subsystems into the central control system is being<br />
performed by experts from IPF and <strong>IPP</strong>, the final “as built”<br />
technical documentation is in progress.<br />
Figure 28: One of the two ECRH-towers. The heavy granite structure<br />
serves as microwave absorber and has the favourable features of an optical<br />
bench.<br />
8.1.3 Transmission System (IPF)<br />
The transmission line consists of single-beam waveguide<br />
(SBWG) and multi-beam waveguide (MBWG) elements.<br />
For each gyrotron, a beam conditioning assembly of five<br />
single-beam mirrors is used. Two of these mirrors match the<br />
gyrotron output to a Gaussian beam with the correct beam<br />
parameters, two others are used to set the appropriate polarization<br />
for optimum absorption of the radiation in the plasma.<br />
A fifth mirror directs the beam to a plane mirror array, the<br />
beam combining optics, which is situated at the input plane<br />
of a multi-beam wave guide (MBWG). The MBWG is designed<br />
to transmit up to seven beams (five 140 GHz beams,<br />
one 70 GHz beam plus one spare channel) from the gyrotron<br />
area (entrance plane) to the stellarator hall (output plane). A<br />
mirror array separates the beams again at the output plane
and distributes them via CVD-diamond vacuum barrier windows<br />
to individually movable antennas (launchers) in the<br />
W7-X torus. Two symmetrically arranged MBWGs are used<br />
to transmit the power of all gyrotrons. In <strong>2007</strong>, a major work<br />
package was the design completion and manufacturing of<br />
the transmission system near the torus. This comprises the<br />
reflectors type M13 and M14, which will be installed in two<br />
“towers” in front of the W7-X ports.<br />
The fabrication of both towers was finished, and the installation<br />
of control systems for reflectors and launchers, support<br />
structures, and granite absorbing plates has started.<br />
Both towers, one of them is seen in figure 28, have to be<br />
stored until W7-X assembly is completed and access is provided<br />
for the installation at their final position in the torus<br />
hall. In the meantime, retro-reflectors were mounted in the<br />
beam-duct in the image plane at half distance of the MBWG<br />
transmission line. Full distance transmission can be simulated<br />
and tested by this arrangement. First calorimetric high<br />
power measurements of the two-pass transmission efficiency<br />
of the first part of the MBWG were performed, yielding a<br />
loss of about 3 % for 10 reflections on the 2×3 MBWG-mirrors<br />
and the 4 additional guiding mirrors, which is in good<br />
agreement with calculations and low power measurements.<br />
This result confirmes the high quality of the quasi-optical<br />
concept for high power, long distance and low loss microwave<br />
transmission.<br />
8.1.4 In-vessel-components (<strong>IPP</strong>)<br />
The design of the front steering ECRH-antennas in the Aand<br />
E-type ports is compatible with full power cw requirements<br />
and was finished in <strong>2007</strong>. The CAD-drawing is<br />
shown in figure 29. Most of the antenna components are<br />
already manufactured, the assembly has started.<br />
Figure 29: ECRH front steering antenna with bi-axially and individually<br />
movable front mirrors<br />
For the two optional high-field side launchers to be installed<br />
in the narrow N-ports, it was decided to adopt the<br />
remote steering scheme, which is based on the imaging<br />
Wendelstein 7-X<br />
57<br />
properties of a square corrugated waveguide. A movable<br />
reflector at the waveguide entrance controls the direction of<br />
the beam injected into the waveguide; at the exit of the<br />
waveguide near to the plasma edge, the beam is launched at<br />
the same angle. For the N-ports, a solution with a bent<br />
waveguide was chosen. This eases the integration of the<br />
waveguides and leads to a lower antenna beam divergence<br />
due to increased waveguide cross-section, but requires<br />
thorough optimization of the position of the mitre bend and<br />
the vacuum valve in the waveguide. The conceptual design,<br />
as well as first optimization calculations have been started.<br />
The ECRH operation range can be strongly extended if<br />
heating scenarios with the second harmonic ordinary mode<br />
(O2) and the third harmonic extraordinary mode (X3) can<br />
be applied. The first enables high plasma density, which is<br />
necessary for efficient divertor operation, the second allows<br />
operation at a lower magnetic field. An incomplete single<br />
pass absorption in the range of 40 % to 80 % has to be<br />
accepted for W7-X parameters. Specially shaped reflectors<br />
made from TZM (titanium, zirconium, molybdenum alloy)<br />
will be installed to avoid the thermal overload of the high<br />
field side heat shield by the microwave shine-through.<br />
After first preliminary high power test in 2006 the reflectortile<br />
was redesigned and its surface was polished to reduce<br />
losses. The watercooled reflector tile was retested in the<br />
ECRH-installation at Greifswald with about 0.5 MW incident<br />
power, which is the expected “worst case” loading for<br />
W7-X. The calorimetrically measured absorption reached<br />
values of 0.3 %, which is consistent with the theoretical<br />
value deduced from the material properties and with previous<br />
low power tests. The surface temperature reaches<br />
470 °C and 390 °C are measured at the cooling plate,<br />
respectively, after 200 s for the worst case, which is acceptable.<br />
The knowledge of the beam position and power load<br />
at the reflector tiles is essential for reliable X3- and O2operation.<br />
An array of small pick-up holes will therefore be<br />
integrated into the tiles to measure the exact beam position<br />
and the single pass absorption. The microwave signal is<br />
transferred by 4 mm copper waveguides towards the B-type<br />
port in the W7-X vacuum vessel. The positions of the<br />
120 pick-up horns and the routing of the related waveguides<br />
were defined in close cooperation with the W7-X<br />
KIP group.<br />
8.1.5 Advanced components and ITER-related R&D<br />
8.1.5.1 Improved e-beam power dissipation at the Gyrotron<br />
collector<br />
The peak power load of the electron beam at the gyrotron<br />
collector is a limiting factor for the next generation cw high<br />
power gyrotrons with 1.5-2 MW output power. The W7-X<br />
Gyrotrons are equipped with a conventional vertical sweep<br />
coil system, which moves the electron beam intersection with<br />
the collector surface up and down in the vertical direction.
This method generates strong power peaking at the turning<br />
points as seen from figure 30 (c), which limits the overall<br />
performance. An almost uniform power deposition is<br />
obtained by adding a rotating transverse field sweeping system<br />
(TFSS, 6 coils, 3 phase power supply, 50 Hz, constant<br />
amplitude). A principle sketch is seen from figure 30 (a).<br />
Figure 30: Principal sketch of the combined (a) Vertical Field (VFSS) and<br />
Transverse Field Sweeping Systems (a) and an amplitude modulated VFSS (b).<br />
(c): Power distribution along the gyrotron collector in vertical (z-) direction<br />
under optimized conditions (red) and with vertical sweep only (black).<br />
The collector surface is now efficiently used and the total<br />
dissipated power can be nearly doubled as shown in figure<br />
30 (c). The combination of both coil systems and the related<br />
power supplies is, however, more complicated and expensive.<br />
A more simple system using TFSS only with a slow amplitude<br />
modulation (6 Hz) superimposed on the 50 Hz beam<br />
rotation as sketched in figure 30 (b) is under investigation.<br />
8.1.5.2 Fast Directional Switch of high power wave beams<br />
The <strong>IPP</strong> Greifswald, IAP Nizhny Novgorod, IPF Stuttgart,<br />
FZ-Karlsruhe, and IFP Milano have established a “Virtual<br />
<strong>Institut</strong>e” of the “Helmholtz Gemeinschaft deutscher Forschungszentren”<br />
with the aim to develop a fast directional<br />
switch (FADIS) for high-power microwave beams. FADIS<br />
is a novel concept and will allow switching and/or combining<br />
high power microwave beams on a fast timescale<br />
(
4<br />
3<br />
2<br />
1<br />
0<br />
intensity [a.u.]<br />
-0.8 -0.6 -0.4 -0.2 0.0<br />
time [ms]<br />
8.1.6 Staff<br />
Staff at <strong>IPP</strong> (W7-X-P and ZTE): B. Berndt, H. Braune,<br />
V. Erckmann, F. Hollmann, L. Jonitz, H. P. Laqua, G. Michel,<br />
F. Noke, F. Purps, T. Schulz, P. Uhren, M. Weißgerber.<br />
Staff at FZK (IHM): A. Arnold, G. Dammertz, J. Flamm,<br />
G. Gantenbein, R. Heidinger (IMF I), M. Huber, H. Hunger<br />
(PMW), S. Illy, J. Jin, S. Kern, R. Lang, W. Leonhardt,<br />
D. Mellein, B. Piosczyk, O. Prinz, T. Rzesnicki, U. Saller,<br />
M. Schmid, W. Spiess, M. Stoner, J. Szczesny, M. Thumm,<br />
J. Weggen, C. Zöller.<br />
Staff at IPF Stuttgart: P. Brand, C. Lechte, M. Grünert,<br />
W. Kasparek, M. Krämer, H. Kumric, O. Mangold, F. Müller,<br />
R. Munk, B. Plaum, S. Prets, P. Salzmann, K.-H. Schlüter,<br />
U. Stroth, D. Wimmer.<br />
Scientific and Technical Staff<br />
W7-X Subdivisions:<br />
Project Coordination<br />
H.-S. Bosch, A. Berg, H.-J. Bramow, J. Dedic, W. Fay,<br />
J.-H. Feist, G. Gliege, M. Gottschewsky, D. Grünberg, K.-H.<br />
Hanausch, D. Haus, U. Kamionka, T. Kluck, B. Kursinski,<br />
A. Lorenz, D. Naujoks, R.-C. Schmidt, M. Schröder,<br />
R. Vilbrandt.<br />
Engineering<br />
F. Schauer, T. Andreeva, V. Bykov, P. Chen, W. Chen,<br />
P. Czarkowski*, W. Dänner*, A. Dübner, A. Dudek, K. Egorov,<br />
J. Fellinger, D. Hathiramani, N. Jaksic, J. Kallmeyer,<br />
J. Kißlinger*, M. Köppen, J. Lingertat*, M. Nitz, F. Scherwenke,<br />
M. Sochor, L. Sonnerup*, A. Tereshchenko, S. Weber,<br />
D. Zacharias, M. Ye.<br />
Wendelstein 7-X<br />
Power<br />
Res<br />
Nonres<br />
Figure 32: Time traces of power signals. green: Gyrotron power. red: power<br />
in resonant path. blue: power in non-resonant path. The gyrotron power<br />
modulation results from the modulation of the acceleration voltage.<br />
59<br />
Design and Configuration<br />
D. Hartmann, G. Adam, M. Banduch, Ch. Baylard*,<br />
D. Beiersdorf, A. Bergmann, P. Biedunkiewicz, R. Binder,<br />
R. Blumenthal, R. Brakel, T. Broszat, P. v. Eeten, N. Fuchs,<br />
H. Greve, N. Hajnal, K. Henkelmann, F. Herold, A. Holtz,<br />
C. Klug, J. Knauer, U. Krybus, L. Mollwo, A. Müller, K. Müller,<br />
A. Okkenga-Wolf, D. Pilopp, T. Rajna*, N. Rüter, P. Scholz,<br />
K.-U. Seidler, B. Sitkowski, F. Starke, M. Steffen, A. Vetterlein,<br />
A. Vorköper, J. Wendorf, U. Wenzel, K. Zimmermann.<br />
Magnets and Cryostat<br />
U. Nielsen*, J. Baldzuhn, M. Bednarek, M. Bensouda-Korachi,<br />
A. Cardella*, D. Chauvin*, G. Croari*,G. Ehrke, A. Friedrich,<br />
D. Gustke, E. Hahnke, A. Hansen, B. Hein, D. Hermann,<br />
K. Hertel, A. Hölting, H. Hübner, H. Jenzsch, P. Junghanns*,<br />
T. Koppe, R. Krause, B. Missal, St. Mohr, A. Opitz, B. Petersen-<br />
Zarling, J. Reich, K. Riße, P.G. Sanchez*, M. Schrader,<br />
R. Schröder, D. Theuerkauf, S. Thiel, V. Tomarchio*, H. Viebke,<br />
S. Wendorf*.<br />
Supply Systems and Divertor<br />
M. Wanner, H. Bau, D. Birus, A. Braatz, C. Dhard,<br />
F. Füllenbach, L. Guerrini*, M. Ihrke, T. Mönnich, M. Nagel,<br />
M. Pietsch, Th. Rummel, M. Schneider.<br />
Assembly<br />
L. Wegener, J. Ahmels, A. Benndorf, T. Bräuer, M. Czerwinski,<br />
A. Domscheidt, H. Dutz, M. Endler, S. Gojdka, H. Grote,<br />
H. Grunwald, A. Hübschmann, F. Hurd*, D. Jassmann,<br />
A. John, S. Jung, A. Junge, R. Krampitz, F. Kunkel, H. Lentz,<br />
E. Müller, H. Modrow, J. Müller, U. Neumann, D. Rademann,<br />
H. Rapp*, L. Reinke, K. Rummel, D. Schinkel, W. Schneider,<br />
U. Schultz, E. Schwarzkopf, Ch. von Sehren, O. Volzke,<br />
K.-D. Wiegand.<br />
Physics<br />
F. Wagner, R. Wolf, T. Bluhm, H. Braune, R. Burhenn,<br />
J. Cantarini*, A. Dinklage, V. Erckmann, P. Grigull,<br />
H.-J. Hartfuss, C. Hennig, U. Herbst, D. Hildebrandt,<br />
M. Hirsch, L. Jonitz, R. König, P. Kornejev, M. Krychowiak,<br />
G. Kühner, A. Kus, H. Laqua, H. Laqua, M. Laux, M. Lewerentz,<br />
G. Michel, I. Müller, U. Neuner, F. Noke, E. Pasch, S. Pingel,<br />
R. Preuß*, F. Purps, T. Richert, J. Schacht, W. Schneider,<br />
A. Schütz, A. Spring, H. Thomsen, P. Uhren, S. Valet, A. Weller,<br />
A. Werner, M. Ye, D. Zhang.<br />
Technical Services (TD)<br />
R. Krampitz, M. Haas, M. Müller, J. Sachtleben, M. Winkler.<br />
<strong>IPP</strong> Garching<br />
Experimental Plasma Physics I (E1): N. Berger, B. Kurzan,<br />
B. Mendelevitch, C. Li, H. Murmann, A. Peacock, B. Petzold,
M. Rott, S. Schweizer, R. Stadler, B. Streibl, R. Tivey,<br />
T. Vierle, S. Vorbrugg, G. Zangl.<br />
Materials Research (MF): M. Balden, H. Bolt, J. Boscary,<br />
H. Greuner, F. Koch, S. Lindig, G. Matern, M. Smirnow,<br />
R. Brüderl, B. Böswirth, J. Kißlinger, K. Bald-Soliman.<br />
Technology (TE): W. Becker, B. Eckert, H. Faugel, F. Fischer,<br />
B. Heinemann, D. Holtum, M. Kammerloher, M. Kick,<br />
C. Martens, P. McNeely, J.M. Noterdaeme, S. Obermayer,<br />
R. Pollner, R. Riedl, N. Rust, G. Siegl, W. Sinz, E. Speth,<br />
A. Stäbler, P. Turba.<br />
Computer Center Garching (RZG): P. Heimann, J. Maier,<br />
M. Zilker.<br />
Central Technical Services (ZTE) Garching: B. Brucker,<br />
H. Eixenberger, R. Holzthüm, M. Huart, N. Jaksic, M. Kluger,<br />
J. Maier, K. Pfefferle, H. Pirsch, J. Simon-Weidner, H. Tittes,<br />
M. Weissgerber, F. Zeus.<br />
Cooperating Research <strong>Institut</strong>ions<br />
Forschungszentrum Jülich (FZJ), Germany: W. Behr,<br />
G. Bertschinger, W. Biel, A. Charl, J. Collienne, G. Czymek,<br />
A. Freund, B. Giesen, D. Harting, H. Jägers, H. T. Lambertz,<br />
M. Lennartz, Ph. Mertens, O. Neubauer, O. Ogorotnikova,<br />
A. Panin, M. Pap, A. Pospieszczyk, U. Reisgen, D. Reiter,<br />
J. Remmel, M. Sauer, W. Schalt, L. Scheibl, H. Schmitz,<br />
G. Schröder, J. Schruff, B. Schweer, W. Sergienko, R. Sievering,<br />
R. Uhlemann, J. Wolters.<br />
Forschungszentrum Karlsruhe (FZK), Germany: A. Arnold,<br />
G. Dammertz, J. Flamm, W. Fietz, G. Gantenbein, R. Heidinger,<br />
R. Heller, M. Huber, H. Hunger, S. Illy, J. Jin, S. Kern, R. Lang,<br />
W. Leonhardt, D. Mellein, K. Petry, B. Piosczyk, O. Prinz,<br />
T. Rzesnicki, U. Saller, M. Schmid, W. Spiess, M. Stoner,<br />
J. Szczesny, M. Thumm, J. Weggen, C. Zöller.<br />
Stuttgart University (IPF), Germany: P. Brand, M. Grünert,<br />
W. Kasparek, M. Krämer, H. Kumric, C. Lechte, O. Mangold,<br />
F. Müller, R. Munk, B. Plaum, S. Prets, P. Salzmann, K.-<br />
H. Schlüter, U. Stroth, D. Wimmer.<br />
Ernst-Moritz-Arndt-Universität Greifswald, Germany:<br />
B. Pompe.<br />
Universität Rostock, Germany: A. Holst.<br />
Universität Stuttgart, <strong>Institut</strong> <strong>für</strong> Kunststoffprüfung und<br />
Kunststoffkunde, Germany: G. Busse.<br />
IPHT – <strong>Institut</strong> <strong>für</strong> Physikalische Hochtechnologie e.V.,<br />
Jena, Germany: W. Ecke, K. Fischer, V. Schultze.<br />
PTB Pysikalische Technische Bundesanstalt Braunschweig,<br />
Germany: H. Schumacher, B. Wiegel.<br />
UKAEA, Culham, UK: B. Brade, M. Tournianski.<br />
Commissariat á L’Energie Atomique (CEA), Saclay,<br />
France: A. Daël, L. Genini, T. Schild.<br />
CRIL Group, Aloytech, France: D. Galindo, G. Vitupier.<br />
CIEMAT, Madrid, Spain: R. Balbin, E. Ascasibar, L. Esteban,<br />
T. Estrada, C. Hidalgo, M. Sanchez, V. Tribaldos.<br />
IST/CFN, Lisbon, Portugal: P. Carvalho.<br />
LT Calcoli, Italy: F. Lucca.<br />
Wendelstein 7-X<br />
60<br />
ENEA Centro Ricerche Energia, Frascati, Italy:<br />
A. Capriccioli, G. Mazzone, L. Semiraro.<br />
CNR Istituto di Fisica del Plasma, Milano, Italy: M. Romé.<br />
CRPP Ecole Polytechnique Federale de Lausanne,<br />
Switzerland: K. Appert, D. Eremin.<br />
Technical University Graz, Austria: W. Kernbichler.<br />
University of Opole, Poland: I. Ksiazek, F. Musielok.<br />
Technical University Szczecin, Poland: P. Berszynski, I. Kruk.<br />
Maritime University of Szczecin (Akademia Morska),<br />
Poland: B. Bieg, Y. Kravtsov.<br />
<strong>IPP</strong>LM <strong>Institut</strong>e of Plasma Physics and Laser Microfusion<br />
Warsaw, Poland: Galkowski, L. Ryc, M. Scholz,<br />
Zzydlowski.<br />
The Henryk Niewodniczanski Instiute of Nuclear<br />
Physics, Kraków (IFJ PAN), Poland: M. Jezabek, Z. Zulek,<br />
M. Stodulski.<br />
Wroclaw Technical University and Wroclaw Technology<br />
Park (WTU WTP), Wroclaw, Poland: M. Chorowski.<br />
Soltan <strong>Institut</strong>e for Nuclear Studies (IPJ), Otwock-Swierk,<br />
Poland: G. Wrochna.<br />
University of Ljubljana, Faculty of Mechanical Engineering,<br />
Ljubljana, Slovenia: J. Duhovnik, T. Kolsek.<br />
Budker <strong>Institut</strong>e of Nuclear Physics, Novosibirsk; Russia:<br />
V. I. Davydenko, A. Ivanov, I. V. Shikhovtsev.<br />
Efremov <strong>Institut</strong>e, St. Petersburg, Russia: A. Alekseev,<br />
A. Malkov.<br />
A.F. Ioffe Physico-Technical <strong>Institut</strong>e of the Russian<br />
Academy of Sciences, Russia: S. Petrov, A. Kislyakov.<br />
Technical University, St. Petersburg, Russia: S. J. Sergeev.<br />
Kurchatov <strong>Institut</strong>e, Moscow, Russia: M. Iasev.<br />
<strong>Institut</strong>e of Applied Physics (IAP), Nizhnynovgorod, Russia:<br />
A. Shalashov.<br />
<strong>Institut</strong>e for Nuclear Research, Kiev, Ukraine: Y. I. Kolesnichenko,<br />
V. V. Lutsenko, Y. V. Yakovenko.<br />
Kharkov <strong>Institut</strong>e of Physics and Technology, Ukraine:<br />
L. Krupnik, A. Melnikov, D. Perfilov.<br />
Research <strong>Institut</strong>e for Particle and Nuclear Physics,<br />
Budapest, Hungary: S. Zoletnik, G. Kocsis, A. Molnár,<br />
S. Récsei, J., Sárközi, A. Szappanos.<br />
Princeton Plasma Physics Laboratory (PPPL), USA:<br />
S. Hudson, A. Reiman, M. Zarnstorff.<br />
Oak Ridge National Laboratory (ORNL), USA: J. H. Harris,<br />
D. A. Spong.<br />
University of Wisconsin, Madison, USA: J. Talmadge.<br />
Kyoto University, Japan: S. Murakami, F. Sano.<br />
National <strong>Institut</strong>e for Fusion Science (NIFS), Toki, Japan:<br />
T. Funaba, S. Okamura, Y. Suzuki, K. Toi, K. Y. Watanabe,<br />
H. Yamada, M. Yokoyama.
WEGA<br />
Head: Dr. Matthias Otte<br />
Laboratory Plasma Devices WEGA and VINETA<br />
Electron Cyclotron Wave Physics<br />
The plasma at WEGA is generated<br />
for low magnetic field operation<br />
of B 0 =60 mT by magnetrons<br />
at a frequency of 2.45 GHz.<br />
The over-dense plasma operation<br />
(>10 times cut-off density for<br />
2.45 GHz) is achieved with mode<br />
conversion Bernstein wave heating.<br />
Raytracing calculations by Preinhalter and Urban, (<strong>IPP</strong><br />
Prague/Czech Republic) confirmed the propagation of the<br />
Bernstein waves in the over-dense plasma region. Although the<br />
WEGA double slot antenna has a symmetric emission profile in<br />
toroidal co- and counter direction, these calculations also showed<br />
a beam propagation in one toroidal direction only, which should<br />
generate Bernstein wave driven toroidal currents. The predicted<br />
current was detected by an external out-of-vessel Rogowski<br />
coil and by the primary coil current at the WEGA transformer.<br />
Power modulation experiments (6 kW on-off at a modulation<br />
frequency of 30 Hz) showed a maximum toroidal current amplitude<br />
of I t =50 A. This current strongly depends on the magnetic<br />
configuration and could even be reversed in case of magnetic<br />
shear reversal. Furthermore, the current density profile inside the<br />
plasma could be measured with small movable Rogowski coils.<br />
This makes WEGA an unique experiment to investigate<br />
Bernstein wave driven currents. The 28 GHz ECRH system was<br />
successfully built and commissioned and is now fully operational<br />
at the second harmonic resonance at 0.5 T. A microwave power<br />
of up to 10 kW is typically used for 15 s plasma operation. The<br />
waveguide system generates an HE11 beam, which is focussed<br />
into the plasma center by an optimized double mirror system inside<br />
the plasma vessel. The resonant character of the absorption<br />
could be verified by on- and off-axis heating experiments.<br />
In argon plasmas a density of n e =4.9×10 18 m -3 and a temperature<br />
of T e =25 eV in the central region could be achieved. Furthermore,<br />
the microwave stray radiation measurement indicates a<br />
strongly enhanced resonant absorption by multiple wall reflections<br />
as predicted by TRAVIS ray-tracing code calculations.<br />
However, in hydrogen discharges an electron temperature<br />
T e >20 eV is achieved already at the plasma edge. For such plasmas<br />
the central region is not longer accessible with simple<br />
Langmuir probes because they start to emit electrons distorting<br />
the characteristics. Therefore, contact-less diagnostics, like Heavy<br />
Ion Beam Probe (HIBP), Electron Cyclotron Emission (ECE),<br />
a bolometer and a reflectometer are being implemented now.<br />
Results from Plasma Experiments<br />
Turbulence studies have been continued in order to identify the<br />
driving instability mechanism and to give a three-dimensional<br />
characterization of the structure of the turbulence. A small<br />
On WEGA experiments were focused on electron<br />
cyclotron wave physics, on fluctuation,<br />
biasing studies and preparations for 0.5 T plasma<br />
operation. Furthermore, the prototype installation<br />
of the W7-X control system made significant<br />
progress. In VINETA it has been achieved to<br />
control drift wave turbulence by influencing nonlinearly<br />
the intrinsic parallel drift wave currents.<br />
The investigations of non-linear wave phenomena<br />
was extended to whistler wave solitons.<br />
61<br />
cross-phase between density and<br />
potential fluctuations is a strong<br />
indicator for drift waves. Additional<br />
hints for drift wave turbulence<br />
could be found, namely<br />
a propagation of turbulent structures<br />
in electron diamagnetic<br />
drift direction after subtraction of<br />
E×B convection and a finite<br />
average parallel wavenumber in<br />
the order of k || ≈10 -2 k θ . The precise<br />
knowledge of the magnetic<br />
field topology allows insight into the parallel dynamics of turbulence.<br />
Turbulent structures in WEGA have a three-dimensional<br />
character and arise preferably on the low field side of the<br />
torus. Furthermore, the influence of magnetic islands on turbulence<br />
was studied. WEGA offers the unique possibility to control<br />
islands and to study turbulence in this region with high<br />
spatial and temporal resolution. Initial experiments showed a<br />
locally enhanced fluctuation amplitude and turbulent transport<br />
in the presence of magnetic islands. Biasing experiments<br />
using carbon probes fitting the shape of the last close flux surface<br />
(LCFS) demonstrated in argon plasmas that a positive<br />
biasing just inside the LCFS increases the poloidal rotation by<br />
a factor of 2 in the maximum. With probe voltages exceeding<br />
+70 V a high temperature regime has been reached with temperatures<br />
of up to T e =25 eV in the vicinity of the LCFS.<br />
Diagnostic Development<br />
The HIBP is a first contactless diagnostic designed for 28 GHz<br />
ECR heated plasmas operation. The ion source was modified<br />
to increase the beam current stability. With an optimised ion<br />
source first profiles of the plasma potential and the total current<br />
were measured. The profiles are in good agreement with<br />
Langmuir probe data. In collaboration with the HIBP group at<br />
TJ-II (Madrid/Spain) and HIBP in KIPT (Kharkov/Ukraine)<br />
modifications of data acquisition and control systems have<br />
been performed in order to decrease the noise level of the<br />
obtained signals. Furthermore, the design of a multi-channel<br />
ECE-system started which will provide information on the<br />
temperature profile of the electrons for 0.5 T operation.<br />
Prototype of W7-X Control System<br />
The setup of a prototype installation of the W7-X control<br />
system is in progress. The central control system, power<br />
supplies, cooling system could be successfully tested in<br />
autonomous operation. An integrated test of all components<br />
is anticipated for the beginning of 2008.<br />
Scientific Staff<br />
D. Andruczyk, O. Lischtschenko, S. Marsen, Y. Podoba,<br />
M. Schubert, T. Stange, G. B. Warr, F. Wagner.
VINETA<br />
Head: Prof. Dr. Olaf Grulke<br />
Device and Operational Parameters<br />
VINETA is a long, cylindrical helicon plasma device, specifically<br />
tailored to study plasma waves and instabilities. The nonresonant<br />
rf helicon wave heating provides high plasma densities<br />
at relatively low electron temperatures (n=1019 m-3 , T ≈3eV e<br />
for a rf frequency f =13.56 MHz, rf power of P =5 kW, and<br />
rf rf<br />
magnetic field B=0.1 T). The main diagnostic tools are electrostatic<br />
and magnetic probes. In addition to standard Langmuir<br />
probe diagnostics advanced active induction probes have<br />
been developed to achieve reasonable signal to noise ratios<br />
at the low frequencies of drift wave and Alfvén wave existence<br />
(f=50 kHz). In the high frequency range induction<br />
probes with high capacitive pickup rejection are used for the<br />
measurements of the magnetic wave field of whistler waves.<br />
Nonlinear Interaction of Drift Waves and Driven Parallel Currents<br />
A key feature of the dynamics of drift wave modes and turbulence<br />
is the parallel electron response associated with the<br />
drift wave instability. Using highly sensitive magnetic probes<br />
the parallel current structure of single saturated drift wave<br />
modes has been measured. Figure 1 shows plasma density<br />
fluctuation pattern and the associated perpendicular magnetic<br />
field fluctuations of a m=3 drift wave mode for two phases of<br />
the drift mode in half of the azimuthal cross section. The magnetic<br />
field fluctuations show the signature of parallel current<br />
filaments, which are correlated with the drift mode pressure<br />
perturbations. To directly influence of the parallel drift wave<br />
currents two approaches are persued: First, a shear Alfvén<br />
wave is excited with a frequency close to the drift wave frequency.<br />
The parallel currents of the drift wave and the Alfvén<br />
wave interact nonlinearly, which is observed as frequency<br />
pulling of the drift mode by the Alfvén wave. Second, a more<br />
y [mm]<br />
80<br />
60<br />
40<br />
20<br />
0<br />
-20<br />
-40<br />
-60<br />
-80<br />
-80 -60 -40 -20 0 -80 -60 -40 -20 0<br />
x [mm] x [mm]<br />
Laboratory Plasma Devices WEGA and VINETA<br />
0.3<br />
0.2<br />
0.1<br />
0<br />
-0.1<br />
-0.2<br />
-0.3<br />
Figure 1: Pressure fluctuations (color coded) and associated perpendicular<br />
magnetic field fluctuations (arrows) for a single m=3 drift mode in the<br />
azimuthal plane perpendicular to the ambient magnetic field.<br />
density fluctuations [a.u.]<br />
62<br />
advanced scheme is to drive mode selective parallel currents<br />
either inductively by a set of eight azimuthally arranged magnetic<br />
saddle coils or with electric contactors in the plasma.<br />
With this mode selective current drive we achieved a full<br />
suppression of the drift wave turbulence. Figure 2 shows an<br />
example of a typical power spectral density for drift wave<br />
turbulence as observed in VINETA and the result of the mode<br />
selective current drive with mode number m=2. In the turbulent<br />
state without current drive the spectrum is broad and displays<br />
a power law decrease for frequencies f≥10 kHz. The<br />
spatiotemporal measurement shows incoherent fluctuations<br />
without any distinct mode number. When parallel currents are<br />
driven, drift wave turbulence is fully suppressed and the fluctuation<br />
energy is transferred into a coherent m=2 drift mode.<br />
S [dB] S [dB]<br />
40<br />
0<br />
-40<br />
-80<br />
40<br />
0<br />
-40<br />
-80<br />
0 10<br />
f [kHz]<br />
20<br />
Whistler Waves<br />
In previous measurements we observed a systematic deviation<br />
of the whistler wave behaviour from the linear dispersion<br />
relation at a frequency of roughly half the electron cyclotron<br />
frequency. At this frequency the whistler wave phase velocity<br />
equals its group velocity and it has been suggested that whistler<br />
wave solitons, so-called oscillitons, might be responsible for the<br />
observed deviations. Dedicated measurements of those deviations<br />
and the associated damping of whistler waves in VINETA<br />
revealed first evidence for the existence of whistler solitons. The<br />
unambiguous identification of oscillitons by wave package dispersion<br />
measurements will be the subject of further investigations.<br />
Scientific Staff<br />
Φ [π] Φ [π]<br />
0<br />
2<br />
C. Brandt, O. Grulke, T. Klinger, J. Pfannmöller, K. Rahbarnia,<br />
A. Stark, N. Sydorenko, S. Ullrich, T. Windisch.<br />
2<br />
1<br />
1<br />
0<br />
0 0.5 1<br />
time [ms]<br />
1.5 2<br />
Figure 2: Power spectral density of plasma density fluctuations and associated<br />
spatiotemporal plot of density fluctuation time series along an<br />
azimuthal circumference for the case of drift wave turbulence (top row) and<br />
the controlled situation when a m=2 current pattern is driven<br />
Part of the VINETA program is carried out under the auspices of the Transregional<br />
Special Collaborative Research Center SFB-TR24 “Fundamentals<br />
of Complex Plasmas”.<br />
δ n [a.u.]<br />
δ n [a.u.]
ITER
Introduction<br />
A major new part of the <strong>IPP</strong> contribution<br />
to ITER during <strong>2007</strong><br />
was via participation in the<br />
design review process. The<br />
design review was divided into<br />
eight working groups who were<br />
charged with evaluating and prioritising<br />
the list of open issues in<br />
the ITER design and with finding proposed solutions to<br />
these issues. <strong>IPP</strong> scientists participated in four of the eight<br />
working groups: Design Requirements and Physics Objectives;<br />
Buildings; Heating and Current Drive; and In-Vessel Components.<br />
The <strong>IPP</strong> also contributes actively to the physics<br />
definition of ITER via the International Tokamak Physics<br />
Activity. <strong>IPP</strong> expertise is in demand for a wide range of activities<br />
in support of ITER, based not only on ASDEX Upgrade<br />
experience but also on know-how in the Technology,<br />
Theory, Materials and Stellarator Divisions. This work varies<br />
from studies of plasma scenarios to work on specific technical<br />
systems and is carried out largely under contracts within<br />
the European Fusion Development Agreement (EFDA).<br />
Heating Systems<br />
Development of RF Negative Ion Sources<br />
In <strong>2007</strong>, the <strong>IPP</strong> RF driven ion source was chosen by ITER as<br />
the new reference source for the ITER neutral beam system.<br />
The main advantages of the RF source are the in-principle<br />
maintenance free operation and the expected much lower Cs<br />
consumption due to the lack of evaporating parts in the source.<br />
Some open issues, however, are still to be addressed: (1) the<br />
simultaneous demonstration of ITER-relevant ion source<br />
parameters for a pulse duration of up to one hour from a<br />
PINI size extraction area; (2) the demonstration of a suffi-<br />
Current / (A)<br />
4<br />
3<br />
2<br />
1<br />
0<br />
45 kW, 0.4 Pa, U ex = 6 kV, j ion = 120 A/m 2<br />
0 10 20 30 40 50 60<br />
Time / (min)<br />
ITER Cooperation Project<br />
Head: Dr. Lorne Horton<br />
Electrons<br />
The <strong>IPP</strong> contributes to the ITER Project in a wide<br />
range of activities. Tasks range from R&D for<br />
heating systems and diagnostics to development<br />
of integrated plasma scenarios. In addition, the<br />
<strong>IPP</strong> is playing a leading role in contributing to<br />
the ITER physics definition and objectives via<br />
contributions to the International Tokamak<br />
Physics Activity and the ITER design review.<br />
Ions<br />
Figure 1: The first stable one hour pulse at MANITU. No feedback control<br />
for electron suppression was necessary.<br />
65<br />
ciently homogeneous large RF<br />
plasma operation with caesium<br />
and negative ion densities in the<br />
required range of a few 10 17 m -3 .<br />
The long pulse test facility<br />
MANITU was further upgraded<br />
by installing a new plasma grid<br />
and an actively cooled bias plate.<br />
With the new setup, stable long<br />
pulses are now possible (figure 1).<br />
The parameters achieved so far are, however, below the ITER<br />
requirements. The main problem for long pulses is still the<br />
rising electron current within the first 100-200 seconds; the<br />
ion current remains stable during the pulse.<br />
The ion source test facility RADI, equipped with a source of<br />
approximately the width and half the height of the ITER<br />
source, aims to demonstrate the required plasma homogeneity<br />
of a large RF source. Full size extraction is not possible.<br />
First results of the homogeneity of a large RF driven deuterium<br />
plasma in volume operation have been obtained.<br />
The experiments at BATMAN concentrate now on basic<br />
studies of negative ion formation and extraction as well as<br />
on electron suppression, on the support of the design of the<br />
ELISE and ITER source and on the further development of<br />
diagnostics. Figure 2 shows as an example the measurement<br />
of the electron energy distribution function (EEDF) using<br />
the so-called Boyd-Twiddy method.<br />
Figure 2: Spatial dependence of the electron energy distribution function of<br />
the <strong>IPP</strong> RF source from the plasma grid (0 cm) to the driver exit (19 cm)<br />
A new test facility ELISE (Extraction from a Large Ion<br />
Source Experiment) is currently being designed for long pulse<br />
and large-scale extraction from a half-size ITER source. ELISE<br />
is an important step between the small-scale extraction experiments<br />
at BATMAN and MANITU and the full size ITER<br />
neutral beam system. Due to the limits of the <strong>IPP</strong> HV system,<br />
only pulsed extraction is possible. The start of integrated<br />
commissioning is planned for the end of 2009. ELISE<br />
makes use to a large extent of existing hardware at <strong>IPP</strong>,
including the cryo system of MANITU and the CODAC<br />
system of RADI. Hence both these test facilities are planned<br />
to be decommissioned in the course of 2009.<br />
<strong>IPP</strong> continued its contribution to the design of the International<br />
Neutral Beam Injector Facility in Padua, Italy. The<br />
main activity of <strong>IPP</strong> is the strong support of RFX Padua –<br />
also by the exchange of personnel – in the design of the full<br />
size RF source and the RF circuit. Smaller activities are the<br />
support of the layout of the source and beam diagnostic system<br />
and the design of an alternative magnetic ion removal system.<br />
ICRF Antenna Design<br />
Substantial progress has been made this year in the definition<br />
of the ICRF antenna. At a meeting in Ringberg, hosted by<br />
<strong>IPP</strong>, the groundwork was laid for the ITER Design Review<br />
working group to recommend that future work would concentrate<br />
on the “ex-vessel matching” option. A number of<br />
tasks were defined by the ITER Design WG. <strong>IPP</strong> contributed<br />
to one of those: the grounding of the antenna. As the antenna<br />
plug is presently only grounded at the port plug flange, the<br />
plug itself works as the inner conductor of a transmission<br />
line. It can therefore sustain eigenmodes, which lead to high<br />
voltages between the antenna plug and the surrounding blankets.<br />
Proper grounding can avoid this.<br />
Europe has also made progress in the legal aspects of setting up<br />
a consortium (CYCLE), which is meant to take the responsibility<br />
for the ICRF antenna design. <strong>IPP</strong> is part of the consortium.<br />
Optimisation of the Upper ECRH Launcher<br />
For the optimization of the “front-steering” launcher, beam<br />
shaping of the radiated antenna beams by waveguide mode<br />
mixtures is under investigation. Converters from smooth circular<br />
waveguide modes to Gaussian beams have been designed.<br />
To enlarge the database on cooling requirements of launcher<br />
mirrors, Ohmic losses of mirror samples that had been<br />
exposed to fusion plasmas were measured with a 3-mirror<br />
resonator at 170 GHz. After one year of operation, launcher reflectors<br />
from ECRH systems of ASDEX Upgrade and W7-AS<br />
showed visible coatings on the surface. As a result, the<br />
Ohmic loss increased by a factor of 1.4 to 1.9 with respect to<br />
an identical new sample. Compared to theoretical values,<br />
the Ohmic loss was higher by factors between 2.3 and 3.0.<br />
ECRH Reliability Data<br />
As part of an EFDA task, the operational experience of the<br />
ASDEX Upgrade ECRH-1 system has been documented with<br />
respect to reliability and main reasons for failures. For this purpose<br />
the old logbooks have been revisited for all pulses between<br />
7.5.1998 and 25.4.2006 in which ECRH was requested (1806<br />
pulses) and a condensed database has been delivered to EFDA.<br />
This information will be recorded in the “Fusion Component<br />
Failure Rate Database” and used as one of the inputs for<br />
making projections of the reliability of the ITER ECRH system.<br />
ITER Cooperation Project<br />
66<br />
Physics Integration<br />
ECRH Physics Integration<br />
Work on the design of the ITER ECRH Upper Launcher was<br />
continued together with partners at CRPP, CNR, FOM and<br />
FZK. An optimization of the mirror design of the reference,<br />
front steering option was analyzed with the aim to minimize<br />
spread in individual beams reflected off one mirror. In the<br />
physics area, work was started on deriving a criterion for FIR<br />
NTM triggering. This criterion will be of the same type as<br />
that for sawtooth stabilisation (i.e. figure of merit I ECCD /d 2 ),<br />
but numerical values can only derived from code modelling<br />
which is in progress. Arrangements have been started amongst<br />
the EU partners to form a consortium that can bid for the<br />
ITER procurement package for the Upper Launcher.<br />
Erosion/Redeposition Studies in PSI-2<br />
In close cooperation with the EFDA group in Garching,<br />
experiments were performed at the PSI-2 plasma generator<br />
in Berlin aiming to test whether nitrogen is suited to serve as<br />
a scavenger gas. Methane was blown into hydrogen discharges<br />
with nitrogen injected into the target chamber.<br />
Deposition or erosion of hydrocarbon layers was monitored<br />
in situ. The various molecules and radicals being produced<br />
in the plasma could be identified using mass spectrometry.<br />
A strong effect was observed in the case of nitrogen injection,<br />
whereas no effect was found for other gases. The variations of<br />
the layer thicknesses were measured on collectors located<br />
either in the target chamber or in the pumping duct. In the target<br />
chamber the growth rate was reduced considerably (0.89<br />
to 0.09 nm/min) while N 2 was blown into the discharge. In the<br />
pumping duct even a reversion from growth (+0.05 nm/min)<br />
to erosion (-0.044 nm/min) could be achieved.<br />
Non-axisymmetric Stability & Resistive Wall Modes<br />
The 3D code package consisting of the CAS3D, STAR-<br />
WALL and OPTIM codes has been applied to stability and<br />
feedback studies of ITER scenario 4. From these studies, it<br />
has been determined that: the no-wall beta limit is β N ~2.3;<br />
the ideal wall limit is β N ~3.55 with a closed wall and ~3.14<br />
for a wall with holes; and no feedback stabilization could be<br />
achieved with β N =2.676. These results suggest that the considered<br />
equilibria and feedback coil system may be inappropriate<br />
for stabilizing the RWM. Nevertheless, before a final<br />
conclusion is drawn, further benchmark calculations with<br />
the MARS, KINX and VALEN codes are required and<br />
remaining differences between codes have to be clarified.<br />
Retention in Mixed Materials<br />
In the framework of an EFDA Task, a study was made of the<br />
retention of fuel ions in mixed materials such as will be<br />
present in ITER. This work is reported in the Plasma-Facing<br />
Materials Chapter of this annual report.
3D Analysis of Impurity Transport and Radiation for ITER Limiter<br />
Start-up Configurations<br />
Three-dimensional modelling of ITER SOL transport during<br />
the start-up limiter phase with the EMC3-EIRENE code has<br />
been extended to include the limiter-released Be production,<br />
transport and radiation. The distributions of the single Be<br />
charge-state densities and line radiation have been simulated<br />
for two plasma densities =0.2 n G , 0.5 n G and three plasma<br />
configurations, I p =2.5, 4.5, 6.5 MA. All Be charge states<br />
exhibit a strong poloidal density modulation due to the small<br />
poloidal extension of the limiters.<br />
Diagnostics<br />
ITER Procurement Package 21<br />
In January <strong>2007</strong> a consortium of the Euratom Fusion<br />
Associations (<strong>IPP</strong>, HAS, FZK, CEA and CIEMAT) under<br />
the leadership of <strong>IPP</strong> began work on the task of providing a<br />
project plan for the full development of ITER Procurement<br />
Package 21 (PP21). PP21 consists mainly of the bolometer<br />
diagnostic and the pressure-gauge diagnostic, but also of all<br />
diagnostic hardware associated with lower port 16, including<br />
that of other “client” diagnostics.<br />
The project plan contains a definition of the scope of PP21,<br />
of the work breakdown structure (WBS), the WBS dictionary,<br />
an implementation schedule and management plans for<br />
risk, procurement, communication, costs and quality. The<br />
project plan developed by <strong>IPP</strong> concentrates on the needs of<br />
the bolometer diagnostic and the port engineering activities.<br />
Aspects of the project plan concerning the pressure gauge<br />
diagnostic are the responsibility of CIEMAT.<br />
HAS contributes with the performance analysis of the system<br />
and the finite element analysis of the thermal behaviour of<br />
bolometer mini-cameras. FZK has made its experience in the<br />
nuclear analysis of the ITER environment available for the<br />
analysis of nuclear heat loads on models of mini-cameras.<br />
CEA contributed with its experience on various bolometer<br />
detector concepts and on irradiation tests. In addition to providing<br />
the project leader, <strong>IPP</strong> provided the lead engineer and<br />
contributed with research activities on the metal-resistor<br />
bolometer detector and to the integration of the diagnostic<br />
into the ITER CODAC system. In order to develop the project<br />
plan and to provide urgently needed data for the integration<br />
of the diagnostic in ITER, a number of R&D and engineering<br />
tasks had to be carried out in parallel to developing the project<br />
plan. The ongoing research activities on the reference metalresistor<br />
bolometer detector were continued and a prototype<br />
with a 4 μm Pt absorber was successfully tested in ASDEX<br />
Upgrade. Irradiation tests are in preparation as are the contracts<br />
with a new cooperation partner for the development of<br />
thin-foil detectors with 12 μm absorbers.<br />
In April a proposal for the LOS distribution was submitted<br />
to ITER. This was further refined in order to account for the<br />
ITER Cooperation Project<br />
67<br />
changes following the ITER design review. Based on this distribution,<br />
an initial performance analysis of the diagnostic was<br />
made. A preliminary ITER bolometer mini-camera and collimator<br />
were designed and adapted to all locations in the divertor<br />
cassettes (an example for divertor cassette 45 is given in<br />
figure 3) and to some in the VV, thus giving the basic definitions<br />
of the interfaces for the integration of the bolometer diagnostic.<br />
Figure 3: Distribution of mini-cameras as foreseen for the locations in<br />
divertor cassette 45<br />
The mini-camera/collimator model was analysed for its thermal<br />
behaviour in the divertor and behind the inner heat shield<br />
under conditions expected for the ITER standard scenario 2.<br />
The results showed that the mini-cameras should be able to<br />
cope with the demanding boundary conditions if sufficient<br />
thermal contact to actively cooled structures can be provided.<br />
In-Vessel Neutral Pressure Measurement<br />
The ASDEX Pressure Gauge (APG) is, at present, the main<br />
candidate for in-vessel neutral pressure measurement in<br />
ITER. The response of conventional APGs is found to saturate<br />
at around 15 Pa, below the ITER requirement of 20 Pa.<br />
With small modifications to the gauge geometry and potential<br />
settings, however, it is possible to obtain monotonic output<br />
with sufficient slope up to the maximum achievable pressure<br />
of 30 Pa at 6 T. The improved pressure range is achieved at<br />
the expense of a lower sensitivity and a somewhat stronger<br />
dependence on the magnetic field.<br />
Test of a Compact Soft X-Ray Spectrometer<br />
A prototype of a compact SXR spectrometer for ITER has<br />
been designed at the Kurchatov <strong>Institut</strong>e in Moscow and is<br />
presently being tested in ASDEX Upgrade. At present, one<br />
spectrometer channel is equipped with a crystal made of<br />
high purity quartz and a deeply depleted back illuminated<br />
CCD camera chip for radiation hardness. The spectrometer<br />
is set to monitor the resonance line of He-like argon. Due to the<br />
large diffraction angle used (≈70°), a high resolving power
of λ/Δλ≈6800 is reached despite the compact dimensions.<br />
First results were obtained during the <strong>2007</strong> campaign allowing<br />
the extraction of Ar concentrations and ion temperatures<br />
in the central plasma with a temporal resolution of 8 ms.<br />
Dust Measurement<br />
The production of dust is an important safety issue for ITER.<br />
Investigations in AUG have been started to compare different<br />
dust measurement techniques and to quantify the dust produced<br />
in a tungsten wall device. Methods under test include a filtered<br />
vacuum collection technique, Si wafer collectors, an in-situ<br />
monitor developed by PPPL and a fast visible camera with a<br />
tangential view. First investigations show spheres of tungsten<br />
with a typical diameter of 1 μm. With a frame rate of 20 kHz,<br />
the fast camera can produced 8 GB of data during one discharge.<br />
Up to now only manual data evaluation has been done.<br />
Typical speeds of 100 m/s are observed for dust particles.<br />
ITER Core Charge Exchange System<br />
Simultaneous observations of charge exchange (CX) transitions<br />
from Ar XVI, XVII and XVIII were obtained in AUG<br />
H-mode plasmas to provide experimental validation of new<br />
fundamental CX cross-sections for Ar. In addition, the influence<br />
of W I and W II line intensities on ITER CX spectra<br />
has been calculated. Using a simple model for W sources, it<br />
is calculated that the CX-lines from C VI and N VII are<br />
unperturbed while the Be IV and He II spectrum has to deal<br />
with only two W I lines. The Ne X and Ar XVIII CX-lines<br />
suffer from several W I lines and therefore may not be suitable<br />
for ion temperature measurements, unless the lines of<br />
sight are chosen with great care.<br />
ITER Design Review<br />
Operating Scenarios for ITER (Current Rise and Current Decay)<br />
In order to achieve the range of scenarios foreseen for ITER,<br />
it is necessary to access a range of q-profiles at the start of the<br />
burn phase. For the ITER Design Review, experimental data<br />
from ASDEX Upgrade have been supplied for two cases.<br />
The first case is based on a dataset of 84 Ohmic pulses with<br />
q 95
Plasma-wall-interactions<br />
and Materials
Surface Processes on Plasma-<br />
Exposed Materials<br />
Simultaneous Irradiation of<br />
Tungsten with D and C at<br />
Elevated Temperatures<br />
Tungsten (W) erosion and carbon<br />
(C) layer growth during simultaneous<br />
irradiation by combined<br />
D + -C2 3<br />
Plasma-facing Materials and Components<br />
Head: Prof. Dr. Dr. Harald Bolt, Dr. Joachim Roth<br />
- ions at 400 °C has been<br />
investigated using the mass-analyzed<br />
dual-beam ion accelerator<br />
at <strong>IPP</strong>. The simultaneous bombardment results in a competition<br />
of erosion and implantation processes that cannot be<br />
described by the linear superposition of the respective pure<br />
species sputtering. Instead, one observes two regimes of<br />
either continuous growth of a C layer or continuous W erosion.<br />
W films deposited on nickel and graphite substrates resulting<br />
in “smooth” and “rough” surfaces respectively, were used as<br />
a model system for irradiation. The different substrates were<br />
chosen to isolate the effect of surface roughness from chemical<br />
erosion, since to this date, no experiments have conclusively<br />
shown a clear correlation between C chemical erosion in the<br />
W matrix, and its effect on W sputter yield and C levels in the<br />
implantation zone. The incident ion energy of D + and C - was<br />
3 keV and 6 keV respectively, and were chosen to obtain the<br />
maximum flux. The dynamics of W sputtering was measured<br />
in-situ by Rutherford Backscattering Spectrometry using<br />
2.5 MeV 3 He ions. Corresponding concentrations of implanted<br />
C and D were measured by Nuclear Reaction Analysis. The<br />
incident C/D ratio was varied over the range 3-20 % and<br />
was determined by a new diagnostic tool, the Beam Viewing<br />
System (BVS), which was able to record in real time quantitative<br />
images of the C and D beam intensities.<br />
For a given C/D ratio at low fluences, the W sputter yield and<br />
total C concentrations at 400 °C deviate little from RT measurements.<br />
However at higher fluences, an increase in W sputtering<br />
and C re-erosion is observed for 400 °C measurements,<br />
resulting in a shift of the transition point from steady state W<br />
erosion to C deposition to higher C/D ratios. Further experiments<br />
at 500 and 600 °C are planned. Experimental results<br />
will be used to benchmark the kinematic code TRIDYN coupled<br />
with the module YCHEM, which provides the chemical<br />
erosion rate of C.<br />
Synergistic Erosion of Hydrocarbon Films Studied by Molecular<br />
Dynamics<br />
Hydrogen isotope retention in carbon-based plasma-facing<br />
materials is a potentially limiting constraint in the long-term<br />
operation of fusion reactors since tritium will be used as<br />
fuel, and hence the tritium inventory build-up may lead to<br />
various safety issues limiting the operation as well as to economic<br />
constraints due to fuel retention.<br />
Within the project “Plasma-facing Materials and<br />
Components” the areas of plasma-wall interaction<br />
studies, material modification under plasma<br />
exposure, development of new plasma-facing<br />
materials and their characterisation have been<br />
merged to form a field of competence at <strong>IPP</strong>.<br />
The work supports exploration and further development<br />
of the fusion devices of <strong>IPP</strong> and also<br />
generates basic expertise with regard to PFCrelated<br />
questions in ITER and fusion reactors.<br />
71<br />
The plasma-facing components<br />
interact with both energetic and<br />
thermal hydrogen species. In<br />
order to understand and quantify<br />
the influence of the energetic particles<br />
on carbon erosion, various<br />
experiments employing hydrogen<br />
ion beams have been performed.<br />
The experiments showed<br />
that the resulting erosion rates at<br />
moderate energies are far higher<br />
than expected from physical sputtering.<br />
The same enhancement was also found in experiments<br />
on the erosion of graphite or amorphous hydrocarbon<br />
films (a-C:H) where the kinetic energy and the chemical<br />
reactivity were supplied by two independent particle fluxes,<br />
a beam of energetic argon ions and another flux of thermal<br />
hydrogen atoms and explained by a rate equation model.<br />
However, the adequacy of this phenomenologically derived<br />
atomistic picture of the erosion mechanism was not clear.<br />
Therefore, molecular dynamics simulations were performed to<br />
gain insight into the atomistic erosion processes resulting in<br />
the unexpected erosion enhancement. After preparation of an<br />
amorphous C:H-sample with 930 atoms with an H/C-ratio<br />
of 0.61 and a density of 1.7 g/cm 3 a comprehensive set of<br />
bombardment simulations has been performed. The simulations<br />
revealed an erosion mechanism which can be described<br />
best as Hydrogen Enhanced Physical Sputtering (HEPS):<br />
First, the energetic argon ions create dangling bonds within<br />
the penetration range. Then the abundant hydrogen atoms<br />
saturate most of the broken bonds in the first few atomic<br />
layers. Subsequent Ar bombardment causes the breaking of<br />
more C-C bonds. The steric repulsion which arises from H<br />
atoms bound to neighboring C atoms in the top layer prevents<br />
the recombination of broken C-C bonds. Finally, the release<br />
of hydrocarbon molecules is caused by a physical sputtering<br />
step. Hence, the emitted molecules are energetic radicals in<br />
contrast to thermalized and saturated hydrocarbon molecules<br />
suggested earlier. The observed HEPS mechanism is a<br />
fast surface erosion process and the time scales are in the<br />
picosecond range.<br />
Characterization of a New Atomic Beam Source<br />
A new beam source for atomic hydrogen was constructed<br />
that will be applied for growth and erosion studies of amorphous<br />
hydrogenated carbon films (a-C:H). The aim was to<br />
develop a source that produces a quantified beam of low<br />
energetic atomic hydrogen (H 0 ) or deuterium (D 0 ) with a<br />
much higher flux than the presently used thermal source.<br />
The new source is based on dissociation of H 2 (D 2 ) in a microwave<br />
plasma. It promises higher flux densities as it features a<br />
high degree of dissociation even at higher pressures. In addition,<br />
a substrate in front of such a source would not be
exposed to thermal loads, as with the old source, and would,<br />
therefore, allow much smaller working distances and consequently<br />
higher flux densities. Furthermore, the source can<br />
also be applied to produce atomic nitrogen as well as atomic<br />
oxygen (using N 2 and O 2 as working gas, respectively)<br />
which will be of interest for future work. The new source<br />
was characterized with molecular-beam mass spectrometry<br />
(MBMS) and with a catalytic sensor in terms of atomic flux<br />
density produced as a function of gas throughput, microwave<br />
power, and distance from the source. Both methods<br />
were cross checked with the standard erosion method of an<br />
a-C:H film at elevated temperature.<br />
To achieve a high degree of dissociation the discharge is<br />
ignited in a quartz tube. Quartz is used because the recombination<br />
coefficient of H 0 (D 0 ) on quartz is very low at room<br />
temperature. For sufficiently long tubes the particle flux<br />
only consists of thermal H 0 (D 0 ) and H 2 (D 2 ) because the<br />
energetic species thermalise due to collisions with the cold<br />
walls of the tube before leaving the source.<br />
The catalytic sensor consists of a 200 μm thin gold plated<br />
nickel disc that is connected with two 25 μm thick thermocouple<br />
wires of the K type and follows the design of<br />
Mozetic. If H 0 (D 0 ) hits the sensor surface it can recombine<br />
to H 2 thereby transferring part of the released binding energy<br />
to the sensor. In equilibrium, the heating due to surface<br />
recombination balances the cooling due to thermal conductivity<br />
of the surrounding gas, thermal conductivity of the<br />
probe, and grey-body radiation. For temperatures up to<br />
500 K cooling by radiation can be neglected so that the temperature<br />
is a direct measure of the flux of atoms onto the<br />
probe tip surface. Because the recombination probability of<br />
H 0 (D 0 ) on the specific surface, as well as the energy fraction<br />
transferred to the sensor is unknown, the sensor is a priori<br />
not suited for absolute measurements, but proved to be valuable<br />
as it allows easy real-time measurements. Because the<br />
sensor surface needs to be activated and can degrade with<br />
time, cleaning by argon sputtering and atomic hydrogen in<br />
vacuum is necessary to activate it and get reliable results.<br />
Both methods reveal, that the H 0 (D 0 ) flux increases with the<br />
flow of H 2 (D 2 ) and decreases with one over the square of the<br />
distance from the exit orifice. Initially the flux increases with<br />
microwaver power, but shows a maximum around 90 W. For<br />
higher power the flux quickly decreases, possibly because<br />
H 0 (D 0 ) recombines on the increasingly hotter tube walls. A<br />
gas independent calibration procedure by reference signals<br />
was developed to achieve absolute quantification of the atomic<br />
flux with the quadrupole. For a tube with an inner diameter of<br />
8 mm the maximum D 0 flux on the beam axis is 1×10 22 m -2 s -1<br />
in a distance of 10 mm given a D 2 -flow of 100 sccm and<br />
90 W microwave power. This flux is more than 2 orders of<br />
magnitude higher than the flux that can be achieved with the<br />
presently used sources which are based on thermal dissociation<br />
of H 2 (D 2 ) in a resistively heated tungsten capillary.<br />
Plasma-facing Materials and Components<br />
72<br />
Migration of Materials in Fusion Devices<br />
Carbon Deposition in the Inner Divertor of ASDEX Upgrade<br />
The deposition of carbon in the inner divertor of ASDEX<br />
Upgrade was determined concomitantly to the transition from<br />
a carbon-dominated machine in the discharge campaign<br />
2002/2003 to a full tungsten machine in <strong>2007</strong>. In the carbondominated<br />
campaign about 15 g of carbon was deposited<br />
on the inner divertor tiles in 3000 s divertor plasma time.<br />
Coating of the upper divertor and the passive stabiliser loop<br />
with tungsten did not significantly change the carbon deposition<br />
in the inner divertor during the campaign 2004/2005.<br />
A substantial decrease of the carbon deposition by a factor<br />
of 5-7 was only observed after coating the ICRF protection<br />
limiters with tungsten in 2005/2006. The remaining carbon<br />
deposited in the inner divertor originated at least partly from<br />
the outer carbon divertor tiles. The replacement of all remaining<br />
carbon tiles at the inner and outer strike points by<br />
tungsten coated ones resulted in a further decrease of carbon<br />
deposition. A large fraction of the inner divertor changed from<br />
a net carbon deposition area to an area without carbon deposition,<br />
where only small residual amounts (about 20 nm) of<br />
re-deposited carbon were observed. Some remaining carbon<br />
deposition was observed below the inner strike point and at<br />
the roof baffle just opposite to the inner strike point.<br />
Electrical arcs burned through the tungsten layers in some<br />
areas of the inner divertor resulting in some carbon erosion.<br />
Beryllium Wall Sources and Migration in L-Mode Discharges after<br />
Beryllium Evaporation in JET<br />
The evolution of gross erosion flux, plasma concentration,<br />
and divertor deposition of the wall constituents (Be, C) in the<br />
JET tokamak has been investigated by spectroscopic measurements<br />
of local Be and C sources and C plasma concentration<br />
directly after 4h extended Be evaporation in a series of<br />
identical 2.5 MA L-mode discharges with 1.5 MW neutral beam<br />
heating. A plasma cross-section with high wall clearance<br />
and divertor strike-points at the horizontal divertor plates was<br />
chosen to optimise spectroscopic lines of sight and to avoid<br />
excessive local erosion. Line intensities of Be II and C II<br />
ions normalised to D α and D β emission of the local D recycling<br />
flux provided information about the time evolution of relative<br />
abundance and surface coverage of both wall materials.<br />
Charge exchange spectroscopy was used to measure the evolution<br />
of the carbon plasma concentration due to the changing<br />
surface composition. In addition, impurity deposition in<br />
the inner divertor was measured by a quartz microbalance.<br />
The extended Be evaporation leads to an initial ≈8-fold<br />
increase of the Be main chamber wall source over the pre-Beevaporation<br />
level and a corresponding reduction of the carbon<br />
source by a factor of ≈2. A similar increase of the Be<br />
source is observed at the outer divertor target plate while in the<br />
inner divertor, the Be source increased only by a factor of ≈3.
In contrast to the main chamber, divertor C sources were only<br />
25 % lower than pre-Be-evaporation level. Both the carbon<br />
wall and divertor sources, and the deposition rate in the inner<br />
divertor increase to a stationary level within the first 3 discharges<br />
still below the initial values before Be evaporation.<br />
Correspondingly, one observes a steep decrease of the Be<br />
sources in the first 3 discharges. In contrast to the carbon<br />
sources, Be sources continue to decrease until the end of the<br />
experiment although with a slower rate than in the initial discharges.<br />
Also the carbon plasma concentration continues to<br />
increase at this slower rate, which shows that unobserved carbon<br />
sources, possibly at main vessel limiters or recessed wall<br />
areas, contribute to the carbon plasma contamination. The Be<br />
source in the outer divertor returns to almost pre-Be-evaporation<br />
level while in the inner divertor the decrease is much less pronounced.<br />
This confirms results of post-campaign analysis of<br />
Be/C coverage on retrieved divertor tiles, which showed that<br />
redeposition of low-Z elements generally prevails in the inner<br />
divertor while the outer target plate is a region of net erosion.<br />
DIVIMP simulations are on the way to interpret the results<br />
and to derive a detailed model of the Be migration pattern.<br />
Tritium Inventory – Understanding and Control<br />
Retention of Deuterium in Tungsten<br />
The ion-driven retention of deuterium in polycrystalline<br />
tungsten was studied theoretically as a function of temperature,<br />
incident ion energy, and incident ion fluence based on<br />
experimental data obtained by thermodesorption spectroscopy<br />
(TDS) and ion beam analysis. Three types of defects<br />
have to be taken into account in order to explain the experimental<br />
results: Intrinsic defects (dislocations, vacancies,<br />
grain boundaries) distributed homogeneously throughout the<br />
whole sample thickness, and ion induced defects (vacancies,<br />
dislocations, deuterium clusters) within a shallow implantation<br />
range (thickness about 100 nm) and ion induced defects<br />
within a modified layer having a thickness of a few μm. Ion<br />
induced defects in the modified layer extend much further<br />
than the ion range, which can be explained by a stress field<br />
induced by the deuterium concentration in the near-surface<br />
layer. At high fluences an additional change of the diffusion<br />
coefficient within the modified layer has to be assumed. This<br />
allows a full description of all experimental observations<br />
(TDS curves, deuterium depth profiles, fluence dependence,<br />
temperature dependence, energy dependence of the amount<br />
of trapped deuterium) with a single set of parameters.<br />
Binding States of Deuterium Implanted into Beryllium<br />
In the context of plasma−wall interaction of hydrogen ions<br />
and beryllium as a first wall material for the future fusion<br />
experiment ITER, the retention of 1 keV H + and D + ions implanted<br />
into clean, single crystalline Be at room and elevated<br />
temperatures is investigated by temperature programmed<br />
Plasma-facing Materials and Components<br />
73<br />
desorption (TPD). Although many studies have been dedicated<br />
to this issue in the past, details of the retention mechanisms<br />
are still unclear, mostly because of oxidised sample surfaces.<br />
In situ XPS measurements show, that the cleaned and<br />
annealed Be sample has residual oxygen concentration<br />
equivalent to 0.2 ML BeO in the near surface region as the<br />
only contamination. Low energy ion spectroscopy (LEIS)<br />
shows, that Be from the bulk covers thin BeO surface layers<br />
above an annealing temperature of 1000 K by segregation,<br />
forming a pure Be-terminated surface which is stable at lower<br />
temperatures until again oxidised by residual gas. No hydrogen<br />
is retained in the cleaned sample above 950 K. Annealing<br />
the sample at 1000 K recrystallises the surface and thus heals<br />
defects in the lattice. By analysis of TPD spectra, active retention<br />
mechanisms and six energetically different binding states<br />
are identified. Activation energies for the release of D from<br />
binding states are obtained by modelling the experimental data<br />
with TMAP7, a code that includes diffusion, trapping, and surface<br />
processes. Together with literature values for solubility<br />
and diffusivity, binding energies (E B ) for D in Be are obtained<br />
(figure 1). Two types of ion induced trap sites (point defects)<br />
with release temperatures between 770 and 840 K (E B =1.69<br />
and 1.86 eV, states 3 and 4) are created at fluences below<br />
1·10 17 cm -2 by the D implantation itself. 80 % of the implanted<br />
hydrogen is trapped in these defects. Two trap sites (states 1<br />
and 2, release between 440 and 470 K with E B =1.06 and<br />
1.14 eV) are created due to local supersaturation of the bulk<br />
above the local saturation concentration of 0.35 D/Be. Implantation<br />
of H and D indicates, that the ion induced trap sites<br />
are influenced by an isotope effect. None of the release steps<br />
shows a surface recombination limit. A thin BeO surface layer<br />
introduces an additional binding state with a release temperature<br />
of 680 K (6). Implantation at elevated temperatures (up to<br />
530 K) changes the retention mechanism above the saturation<br />
limit. A phase transition due to the elevated substrate temperature<br />
leads to the formation of increasing amounts of BeD 2 in<br />
the supersaturated areas, which decomposes at 570 K (5).<br />
Temperature [K]<br />
300<br />
400<br />
500<br />
600<br />
700<br />
800<br />
900<br />
1000<br />
(5)<br />
E<br />
S<br />
=<br />
- 0.1 eV<br />
(1) (2)<br />
(6)<br />
(3)<br />
(4)<br />
E<br />
Desorption rate of<br />
D 2 (m/q = 4) [a.u.]<br />
∆ED = 0.29 eV<br />
Mobile<br />
state<br />
- 1.69 eV<br />
- 1.86 eV<br />
- 1.06 eV<br />
Ion-induced<br />
defects<br />
BeD2<br />
Supersaturation<br />
Be bulk<br />
BeO-D<br />
E0 = 0 eV<br />
D atom<br />
EBE (1/2 D2) =<br />
- 2.28 eV<br />
D2 molecule<br />
Surface<br />
∆EAdsorbed =<br />
0.87 eV<br />
Figure 1: Schematic energy diagram of the binding states of deuterium<br />
implanted into beryllium (right side) and a typical TPD spectrum (left side).<br />
The horizontal arrows assign the identified binding states to experimental<br />
desorption peaks (1-6).
Ion Beam Analysis of Deuterium Retention in Be/D<br />
Co-Deposited Layers<br />
The co-deposition of Be and D will be a challenging problem<br />
for ITER: Due to the large Be covered first wall area in ITER<br />
and the high physical sputtering yield of Be plasma concentrations<br />
of up to percent levels can be expected in the ITER<br />
divertor. This results in an influx of Be and D onto the divertor<br />
elements that can lead to deposition of thick Be layers containing<br />
a fraction of D that depends on surface temperature,<br />
particle energy and the Be flux fraction. The dependence of the<br />
D/Be ratio on these parameters is yet unknown since a large<br />
scatter in the available data exists. To remedy this situation dedicated<br />
experiments have been performed at the PISCES-B<br />
facility at UC-San Diego: A solid Be sample was exposed to a D<br />
plasma and the eroded Be and D reflected from the sample were<br />
collected on a temperature controlled disc that was shielded from<br />
direct plasma impact. In these experiments the disc temperature<br />
and D ion energy were varied. The Be/D ratio in the co-deposited<br />
layers on these discs was analysed by ion beam analysis<br />
at <strong>IPP</strong>. Both the Be and D areal density were measured using<br />
nuclear reaction analysis (NRA) at the <strong>IPP</strong> tandem accelerator.<br />
A2MeV 3 He ion beam was used to simultaneously measure<br />
both the Be and D areal densities utilizing the Be( 3 He,p)B and<br />
D( 3 He,p)a reactions, respectively. The energy of 2MeV was<br />
chosen to yield a roughly constant cross-section for both<br />
nuclear reactions through out the co-deposited layer. The typical<br />
layer thickness was in the order of several hundred nm.<br />
The NRA results showed that the Be/D ratio in these layers<br />
varies from 0.005-0.7 depending on disc temperature and D<br />
ion energy. Two general trends can be observed: The D/Be<br />
ratio decreases with increasing deposition rate and increasing<br />
temperature and it increases with D ion energy. This<br />
behaviour can be qualitatively understood: High deposition<br />
rates require a higher Be flux fraction onto the disc and thus<br />
a lower D/Be ratio. High temperatures lead to an increased<br />
loss of D due to effusion during layer deposition and therefore<br />
results in a lower D/Be ratio. Higher D ion energy also<br />
means that the reflected D that is co-implanted with the Be at<br />
the collector disc has a higher energy resulting in a thicker<br />
implantation zone and thus increased D accumulation.<br />
Fuel Retention in ITER-Relevant Mixed-Materials<br />
It is expected that mixed material layers will develop on the<br />
wall surface of ITER resulting from the interaction of plasma<br />
and plasma-facing materials (Be, W and CFC). The understanding<br />
of hydrogen retention in such mixed material system is important<br />
for a reliable extrapolation of in-vessel tritium retention<br />
of ITER. In this study, D retention in “binary systems” and<br />
ITER-relevant “mixed layers” (Be 2 C, Be 12 W and tungsten carbide)<br />
was investigated under controlled laboratory conditions.<br />
Binary system samples were prepared as thin films of about<br />
200 nm on a substrate. The following film/substrate combinations<br />
investigated in this study were: C/Be, C/W, Be/C,<br />
Plasma-facing Materials and Components<br />
74<br />
Be/W, W/C, W/Be. C and W films were deposited by magnetron<br />
sputter deposition and Be films by thermionic vacuum<br />
arc deposition. Some of these samples were subsequently<br />
annealed at defined temperatures for the fabrication of<br />
mixed layers. 200 eV D ion implantation into the sample with<br />
a flux of ≈3×10 19 D/m 19 s 1 was performed in the <strong>IPP</strong> High<br />
Current Ion Source at room temperature. After reaching predefined<br />
values of fluence (up to ≈4×10 24 D/m 2 ), the amount<br />
of D retained in the samples was measured by nuclear reaction<br />
analysis.<br />
Figure 2: Fluence dependence of D retention in (a) carbon-coated samples,<br />
(b) Be-coated and Be-related mixed layer samples and (c) W-coated and<br />
W-related mixed layer samples, together with the literature data of each<br />
pure material.<br />
The results are summarized in figure 2. In the case of C or Be<br />
coating, the D retention is predominantly determined by the film<br />
with almost no influence of the substrate. This is probably<br />
because D diffusion in C or Be at room temperature is negligible,<br />
i.e. most of D is retained within the implantation range.<br />
Eventually, D retention in the films saturates at a certain amount.
In both C and Be films, the D saturation level for 200 eV D<br />
implantation is ≈7.0×10 20 D/m 2 . D retention in W coated<br />
samples shows no clear saturation in this fluence range. On<br />
the other hand, D bulk accumulation is inhibited, because at<br />
room temperature D diffusion in the substrate material (Be<br />
or C) is much lower than in W. As a consequence, the total<br />
retention in the high fluence range in such thin W films is<br />
lower compared to poly-crystalline (PCW) bulk tungsten.<br />
D retention in Be 2 C, Be 12 W and tungsten carbide layers increases<br />
with the incident fluence as ≈Φ 0.2 (Be 2 C, Be 12 W) and<br />
≈Φ 0.4 (tungsten carbide), respectively (see figure 2b and c).<br />
Moreover, D retention in Be 2 C and Be 12 W is comparable to<br />
that of pure Be. Tungsten carbide shows similar fluence<br />
dependence as PCW rather than graphite.<br />
Permeation of Deuterium through Tungsten<br />
The ion-driven permeation of deuterium through 50 μm thick<br />
tungsten foils was investigated at elevated temperatures in the<br />
range of 823-923 K, incident fluxes of 10 13 -10 14 D/sec/cm 2<br />
and ion energy of 200 eV. The effective diffusivity for deuterium<br />
transport through the samples is about four orders of<br />
magnitude smaller than the classical Frauenfelder’s values.<br />
This can be explained by the strong influence of defects.<br />
Simulation calculations using the TMAP-7 code give a detrapping<br />
energy of about 2.3 eV for these defects, and these<br />
high-energy traps govern the diffusion process in the investigated<br />
temperature range. The recombination coefficients for<br />
the front and back sides have also been estimated. Sputter<br />
cleaning of the surfaces increases the recombination coefficient<br />
by several orders of magnitude.<br />
Materials – Processing and Characterisation<br />
Structural Investigation of Metal-Doped Carbon Films<br />
Doped carbon materials show strongly reduced erosion yields<br />
compared to pure carbon. This is due to an influence on the erosion<br />
mechanism and the successive formation of a protective<br />
metal-enriched surface region. Amorphous metal-doped carbon<br />
films (a-C:Me) have recently been used for systematic erosion<br />
studies. To investigate the influence of the film structure on the<br />
erosion process, basic information about the metal distribution<br />
and the structure of the carbon matrix is required. Therefore,<br />
the structure of a-C:Me films was systematically analysed.<br />
The investigated parameters were type of doping metal<br />
(Me=W, Ti, V, Zr), metal concentration (
In previous experiments it was demonstrated that W alloys containing<br />
Si form a protective SiO 2 layer in air at elevated temperatures,<br />
which reduces the oxidation rate. Using the ternary<br />
alloys W-Si-Cr, W-Si-Y, and W-Si-Zr, the oxidation behaviour<br />
was further improved. The Arrhenius plot in figure 3 shows the<br />
comparison of the oxidation rates k (= mass gain due to oxidation<br />
per square centimetre and second) of pure tungsten, binary, and<br />
ternary alloys at different temperatures. The contents of the additives<br />
are given in weight percent in the alloy notation. From<br />
the investigated samples the WSi8Cr12 alloy shows the highest<br />
reduction of k by more than two orders of magnitude in the<br />
whole investigated temperature range from about 900 to 1300 K.<br />
The oxidation rate of this Cr-doped alloy is about a factor of<br />
10 lower than that of the corresponding Cr-free alloy WSi13.<br />
MoS 2 Coatings for W7-X<br />
During operation of the W7-X stellarator, high forces act between<br />
the superconducting coils. Therefore the coil casings are<br />
reinforced among each other by narrow support elements (NSE).<br />
For the pads inside the NSEs, a lubricant coating had to be developed,<br />
which works in high vacuum under cryogenic temperatures<br />
and which withstands the loads. Another challenge<br />
was, that the coating has to ensure the expected lifetime of<br />
W7-X without access for service and maintenance of the<br />
NSEs after assembly of the experiment.<br />
The materials research division of <strong>IPP</strong> Garching developed an<br />
anti-friction MoS 2 coating which meets these requirements.<br />
The applied MoS 2 coating is very thick (about 8 μm) compared<br />
to the usually applied coating thicknesses of about 1 μm.<br />
Nevertheless the MoS 2 layers show no columnar structure.<br />
This is important, because columns will break under load.<br />
Tests under high loads confirmed/approved that the coating<br />
will protect the pad surface for the designated lifetime.<br />
Transfer of the specific sputter deposition parameters to industrial<br />
scale was not successful. The MoS 2 layers provided by<br />
industrial partners showed columnar structure, lower lifetime,<br />
and unsatisfying adhesion properties. Therefore, all NSE pads<br />
for W7-X will be coated at <strong>IPP</strong> Garching using the available<br />
magnetron sputter device.<br />
Metal Matrix Composites<br />
In future fusion reactors like DEMO, the fusion plasma leads to<br />
a heat flux of typically 15 MW/m² in the divertor region. The<br />
heat has to be removed efficiently from the plasma-facing<br />
material (W, C) through the copper-based heat sink to the cooling<br />
channels. According to the power plant conceptual study<br />
(model A), it is desired to increase the cooling water temperature<br />
to at least 300 °C for efficient energy production. Depending<br />
on the divertor design, this will lead to high temperatures of up to<br />
550 °C at the interface between plasma-facing material (W, C)<br />
and heat sink material (Cu, CuCrZr). The mechanical properties<br />
of the current Cu-based material at this high temperature are<br />
insufficient. Additionally, due to the temperature gradient and<br />
Plasma-facing Materials and Components<br />
76<br />
different coefficients of thermal expansion (CTE) of W and Cubased<br />
materials, high stresses occur at the interface of PFM and<br />
the heat sink material. The metal-matrix composite (MMC)<br />
W-fibre-reinforced Cu has the potential to strengthen this zone<br />
and shows great promise to improve the mechanical performance<br />
at high temperatures compared to conventional Cu-based<br />
alloys. The focus was placed on the optimization of the interface<br />
to achieve an enhanced adhesion between W fibre and Cu<br />
matrix. Five different interfacial concepts (e.g. pure copper<br />
PVD interlayer, a graded transition PVD interlayer from<br />
100 % W to 100 % Cu) and six different microstructuring concepts<br />
(e.g. chemical etching, ion etching, fibre twisting) were<br />
chosen to modify the tungsten fibre surface to achieve enhanced<br />
interfacial adhesion. The interfacial properties were investigated<br />
through pull-out measurements of single matrix-coated<br />
fibres. Concerning the different interfacial concepts, up to 6 fold<br />
increase in shear strength was achieved by depositing a graded<br />
transition between W and Cu plus additional heat treatment.<br />
Regarding the different microstructuring concepts, the highest<br />
effect on interfacial adhesion between Cu and W (up to 3 fold<br />
increase in shear strength) was achieved by fibre twisting to 30°.<br />
Additionally, multi-fibre metal-matrix composites with the<br />
best interfacial concept were synthesized using the Matrix-<br />
Coated-Fibre (MCF) procedure. Discs of the MMCs were<br />
thermally cycled between 350 °C-550 °C to investigate the<br />
thermal stability and the behaviour of the fibre-matrix interface<br />
which can be critical due to the CTE mismatch of W and Cu.<br />
After 120 cycles no debonding of the W fibre from the Cu<br />
matrix was observed. Therefore, the thermal stability of the<br />
MMC in thermal cycling tests can be assured by depositing<br />
a stepwise graded transition between W fibre and Cu matrix.<br />
Figure 4: SEM images of the twisted and chemical etched W fibre a) and its magnification<br />
b) used to achieve enhanced interfacial adhesion in a copper matrix<br />
Component Behaviour<br />
Probabilistic Failure Assessment of an Embrittled Tungsten<br />
Divertor Structure<br />
Inherent brittleness and neutron embrittlement are the most<br />
critical weaknesses of tungsten for fusion application. Pronounced<br />
scattering of the fracture strength of tungsten requires
a statistical treatment. Thus, the risk of structural failure of a<br />
tungsten component can be estimated only in a probabilistic<br />
framework. To this end, we applied a probabilistic failure analysis<br />
code STAU to estimate the performance of a water-cooled<br />
tungsten mono-block divertor component. The STAU code is<br />
based on the weakest-link failure theory and linear elastic fracture<br />
mechanics. A heat flux load of 15 MW/m² and a coolant<br />
temperature of 320 °C typically expected for a water-cooled<br />
fusion reactor were considered for the FEM stress analysis.<br />
The failure probability was computed considering various<br />
fracture criteria. Both the experimental (unirradiated tungsten)<br />
and hypothetical Weibull parameters were used as material<br />
data. The measured parameters were 31 (shape modulus) and<br />
2353 MPa (scale parameter), respectively. The hypothetical<br />
shape parameters ranged from 5 to 20 whereas the assumed<br />
scale parameters from 1500 to 2500 MPa. In the case of unirradiated<br />
tungsten, the failure probability was acceptably small<br />
ranging from 0.025 % (surface cracks) to 0.08 % (volume<br />
cracks). When either the Weibull modulus or the scale parameter<br />
was hypothetically reduced, the resulting failure risk was<br />
significantly increased far beyond a tolerable level. This result<br />
clearly demonstrated the essential impact of embrittlement<br />
on the failure behaviour. The most dangerous regions were<br />
identified to be the narrow stress concentration domains<br />
near the free surface edge of the bond interface between the<br />
tungsten block and the copper cooling tube.<br />
High Heat Flux Test Facility GLADIS: Test of W7-X-Target<br />
Elements<br />
The aim of the GLADIS facility (Garching LArge DIvertor<br />
Sample test facility) is to provide thermal testing capabilities<br />
for highly heat loaded divertor components which have both<br />
active water cooling and large outer dimensions. In <strong>2007</strong>,<br />
approximately 35,000 pulses of typically 10 to 25 MW/m 2<br />
heat flux density and pulse lengths between 10 s and 45 s have<br />
been applied on the test samples. The technical improvement<br />
of the facility resulted in a further extension of pulse length and<br />
pulse repetition rate, respectively. As a new option a helium<br />
beam can be generated with similar parameters in addition<br />
to the hydrogen neutral beam for standard operation.<br />
The main tasks of GLADIS in <strong>2007</strong> were the continuation of<br />
thermo-mechanical qualification test for the actively cooled<br />
W7-X pre-series divertor target elements and the participation<br />
in the JET ITER-Like Wall Project to qualify the industrial<br />
W coatings of CFC tiles.<br />
More than 65 % of GLADIS operation time was dedicated to<br />
high heat flux testing of a new set of W7-X pre-series divertor<br />
targets. As most important result of the high number cyclic<br />
loading tests can be summarized that a sudden defect of the<br />
divertor due to loss of CFC tiles does not have to be expected<br />
during plasma operation in W7-X. In previous test campaigns<br />
of more than 30 full-scale elements the heat removal capability<br />
of the W7-X target concept (flat tiles of CFC NB31 as plasma<br />
Plasma-facing Materials and Components<br />
77<br />
facing material bonded by an Active Metal Casting (AMC ® )<br />
copper interlayer onto a water-cooled CuCrZr structure) has<br />
been demonstrated for the envisaged operational power load of<br />
10 MW/m². No large detachment or loss of CFC tiles occurred<br />
during cyclic loading tests at 10.5 and 13 MW/m², but growing<br />
local debonded zones at the free edges of several CFC<br />
tiles were observed on the previous prototypes.<br />
As a consequence, detailed 3/D non-linear thermo-mechanical<br />
FEM analysis of the system of CFC/Cu bonding with respect to a<br />
further reduction of the stress at the CFC/Cu interface were<br />
carried out by the manufacturer PLANSEE SE. As result a set of<br />
17 additional pre-series elements was manufactured to investigate<br />
the thermo-mechanical behaviour of the three most promising<br />
design variations (for further information see chapter 3 –<br />
Wendelstein 7-X, section 3.5.1 – Target Modules). For the preferred<br />
design variation with the insertion of an additional compliant<br />
Cu interlayer between AMC ® and CuCrZr cooling structure,<br />
so called “bi-layer” and shown in figure 5, a 50 % reduction<br />
of stresses and strains in the CFC/Cu interface was predicted.<br />
Figure 5: Cross section of CFC/Cu bonding of bi-layer type after 5000<br />
cycles 10 MW/m². The image clearly shows the good joining quality of the<br />
Cu interlayer and the good CFC/AMC® bonding.<br />
The extended cycling of two elements with more than 5000<br />
cycles at 10 MW/m 2 confirmed the significantly higher reliability<br />
of this type of CFC bonding. The targets were loaded with a<br />
Gaussian heat flux distribution to study the evolution of bonding<br />
defects depending on cycle number and local heat load. A<br />
target length of 75 mm was loaded with 10 MW/m² on average,<br />
the surfaces close by with load profiles between 9-7.5 MW/m².<br />
The results of IR examination during these heat loading tests<br />
are summarized in figure 6. For six identified growing hot<br />
spots, the measured local surface temperature increase is correlated<br />
to an expected size of debonding at the CFC/Cu interface<br />
on the basis of thermal FEM calculations. The metallographical<br />
analysis after testing confirmed that all observed growing hot<br />
spots originated from a CFC/Cu de-bonding on the free edge.<br />
The predicted de-bonding sizes of small hot spots are in<br />
good agreement with the metallographically measured sizes.<br />
The defects D1 and D2 were identified as slowly growing<br />
defects for the applied heat flux density of 10 MW/m². For the<br />
largest failure D1, the measured CFC surface temperature of<br />
1755 °C after 5000 cycles of 10 MW/m² should be acceptable
for operation in W7-X. Growing defects were clearly detected<br />
in an early stage of 10 MW/m² HHF testing. The defects D5<br />
and D6, 10 MW/m² loaded as well, are very small and practically<br />
stable defects. No significant progress of existing debonding<br />
was observed for heat loads
Plasma Theory
Tokamak Physics Division<br />
Head: Prof. Dr. Sibylle Günter<br />
Tokamak Edge Physics Group<br />
Work in the group has balanced<br />
the use of existing codes to understand<br />
phenomena in the edge plasma<br />
(or to identify discrepancies<br />
between code and experiment),<br />
and the improvement of the codes.<br />
Current edge codes form an important<br />
bridge between results<br />
on present machines and divertor operation on ITER. The<br />
present ITER divertor is based to a large extent on the results<br />
of simulations with one of the existing edge codes, while a<br />
number of edge codes are in use to understand present day<br />
experimental results. To place the ITER predictions on a<br />
firmer footing, an effort has been made to verify the existing<br />
codes by careful code-code comparison, and then to validate<br />
the codes against the experiment. This is done within the<br />
framework of an ITPA DivSOL activity (DSOL-14), and<br />
also as part of the activities of the EU Task Force on<br />
Integrated Tokamak Modelling. In 2004, the results of the<br />
EDGE2D-NIMBUS, B2-EIRENE (SOLPS5) comparison<br />
for the D only case were reported together with some preliminary<br />
results with drifts. During the <strong>2007</strong> JET edge modelling<br />
campaign, these results were extended to D+C for<br />
SOLPS, and some results for D and D+C for EDGE2D-<br />
NIMBUS and EDGE2D-EIRENE were also obtained. One<br />
of the major results was a renewed look at the atomic<br />
physics being used in the edge codes. For one particular<br />
case, the peak target electron temperature was found to<br />
change by a factor of nearly 10 depending on the choice of<br />
atomic physics (for hydrogen).<br />
In-depth examination of earlier identified discrepancies<br />
between SOLPS modelling and AUG experimental data was<br />
continued. Three types of discrepancies – in the divertor<br />
electron temperature T e , radial electric field E r and Mach<br />
numbers of parallel ion flow in the main scrape-off layer<br />
(SOL) M || – were linked together. A consistent picture of the<br />
problems encountered by the code modelling has been confirmed.<br />
The leading assumption about the origin of the discrepancies<br />
is the neglect of kinetic effects in the parallel electron<br />
heat transport from the SOL to divertor. Analysis of publications<br />
related to the role of kinetic effects in the SOL reveals<br />
a significant effect which they can have on the electron distribution<br />
function near the target, resulting in higher parallel<br />
electron heat flux and a large Debye sheath drop at the target.<br />
Work has started on developing a kinetic treatment for the<br />
edge plasma, with the intention of either coupling this to B2,<br />
or to try to parameterize the results in some fashion for<br />
inclusion in the fluid plasma code. In continuation of a project<br />
on disruptions at JET, a series of modified pre-disruptive<br />
Theoretical Plasma Physics<br />
Head: Prof. Dr. Per Helander<br />
The project “Theoretical Plasma Physics” is devoted<br />
to first-principle based model developments<br />
and combines the corresponding efforts of<br />
the divisions Tokamak Physics and Stellarator<br />
Theory, of the Junior Research Groups “Turbulence<br />
in Magnetized Plasmas”, “Theory and Ab Initio<br />
Simulation of Plasma Turbulence”, and “Computational<br />
Material Science”, and the EURYI Research<br />
Group “Zonal Flows”. It is headed by one theorist<br />
on the board of scientific directors at a time.<br />
81<br />
JET equilibria has been subjected<br />
to thermal quench modelling<br />
with the SOLPS package.<br />
Development of version 6.0 of<br />
the SOLPS package supporting<br />
adaptive mesh refinement has<br />
continued. Based on the current<br />
implementation of the B2 fluid<br />
code, approaches to implement a<br />
generalized framework for the solution<br />
of the fluid equations have<br />
been studied. The main focus lies<br />
on higher-order schemes for conservation laws on unstructured<br />
quadrilateral meshes and efficient data structures enabling<br />
later parallelization of core components of the code.<br />
Other work included: (1) continuing activities associated<br />
with the EFDA Task Force on Integrated Tokamak Modelling;<br />
(2) maintenance, support, and further development of<br />
the SOLPS code; (3) supporting the use of SOLPS at <strong>IPP</strong> to<br />
(i) explore the differences between L- and H-mode edge profiles<br />
in terms of the derived transport coefficients, (ii) explore<br />
the impact of a killer gas puff on AUG, and (iii) explore the<br />
process of detachment.<br />
MHD Theory Group<br />
Heat Transport in Magnetic Islands<br />
Heat diffusion studies using a recently developed numerical<br />
scheme were continued. For cylindrical geometry, heat diffusion<br />
across magnetic islands and ergodic layers has been<br />
studied in detail. The effect of the observed island temperature<br />
flattening on the stability of Neoclassical Tearing Modes<br />
was examined. It was found that the neoclassical island drive<br />
is significantly stronger for realistic island parameters than<br />
predicted by Fitzpatrick 1 .<br />
A new code has been implemented which applies the numerical<br />
scheme to toroidal geometries using straight field line<br />
coordinates. First results for magnetic islands and ergodic<br />
layers in realistic ASDEX Upgrade equilibria suggest that<br />
cases with realistic heat diffusion anisotropies can be very<br />
well resolved.<br />
Fully Three-dimensional Resistive Wall Mode and Feedback<br />
Stabilization Studies<br />
The feedback stabilization of Resistive Wall Modes (RWMs)<br />
has been studied in the presence of multiply connected wall<br />
structures using the fully three dimensional CAS3D, STAR-<br />
WALL, and OPTIM codes. The coupling of toroidal modes<br />
in 3D has been taken into account. The codes have been<br />
applied to an ITER and an ASDEX Upgrade like equilibrium<br />
with β N =2.51 and β N =2.62, respectively. For both cases stable<br />
solutions have been found.<br />
1 R. Fitzpatrick, Physics of Plasmas 2, 825 (1995)
While for the ITER wall the mode coupling is negligibly small,<br />
the complex structure of the additional AUG wall segment leads<br />
to a significant coupling of the n=1 and n=2 toroidal harmonics.<br />
Furthermore, the feedback optimization code OPTIM has<br />
been supplemented with a robust control package. Eigenvalue<br />
sensitivity is now taken into account by the concept of<br />
pseudospectra. The computed feedback controllers are optimally<br />
robust with respect to, e.g., model imperfections, and<br />
transient amplifications of initial perturbations are kept at a<br />
moderate level.<br />
Preliminary investigations indicate that both robustness and<br />
transient growth could be a severe issue when attempting to<br />
stabilize RWMs in ITER.<br />
Kinetic MHD and Fast Particle Physics<br />
A comprehensive and self-consistent kinetic investigation of<br />
global fast particle driven modes in tokamak plasmas below<br />
the toroidal Alfvén Eigenmode (TAE) frequency requires<br />
the inclusion of the bulk ion compressibility. This extension<br />
enables the linear gyro-kinetic eigenvalue code LIGKA to<br />
analyse the low-frequency properties of the Alfvén cascade<br />
modes (AC), the beta-induced Alfvén eigenmodes (BAE)<br />
and the energetic particle modes (EPM). Furthermore, also<br />
the linear phase of micro-instabilities like ion-temperaturegradient<br />
modes, trapped-particle modes or micro-tearing<br />
modes can now be described with LIGKA. Thus, it closes<br />
the gap between global low-n MHD descriptions and high-n<br />
micro-scale turbulence codes (in their linear phase). As an<br />
application, the kinetic damping mechanisms of the resistive<br />
wall modes have been investigated. It was found that not<br />
only the sound wave damping near the rational surfaces contributes<br />
but also the coupling to the electrostatic drift branch<br />
modifies the mode structure and therefore modifies the<br />
damping rate.<br />
Linear MHD Stability Analysis<br />
Within the Integrated Tokamak Modelling effort (IMP#1), a<br />
matching suite for optimized linear MHD stability analysis<br />
has been created by improving and adapting the converter<br />
tool RWSHOT for experimental shotfiles, the fixed boundary<br />
equilibrium code HELENA, and the linear MHD stability<br />
code ILSA.<br />
It is now possible to calculate the linear MHD spectrum of<br />
edge modes vs. their toroidal mode number starting from<br />
free boundary equilibria generated by the equilibrium codes<br />
CLISTE and EFIT, thereby facilitating comparison of most<br />
major tokamak devices in the fusion community. In the light<br />
of this new possibility, benchmarking studies of edge stability<br />
have been carried out at DIII-D and ASDEX Upgrade,<br />
highlighting the influence of near-X-point geometry on the<br />
stability of the peeling-ballooning mode. While there is<br />
good agreement on the stability of the ballooning term,<br />
results with respect to the pure peeling and kink terms<br />
Theoretical Plasma Physics<br />
82<br />
remain inconclusive due to numerics limitations in the<br />
vicinity of the X-point. Further, potentially analytical, effort<br />
is needed to elucidate on the relevance of the peeling mode<br />
in strongly sheared geometries.<br />
Non-linear MHD Studies<br />
The locking of neoclassical tearing modes (NTMs) by error<br />
fields was studied numerically. In the regime with low mode<br />
frequency and large plasma viscosity, the required field<br />
amplitude for mode locking is found to be proportional to<br />
the plasma viscosity and the mode frequency but inversely<br />
proportional to the square of the magnetic island width and<br />
the Alfvén velocity, indicating that NTMs will be locked to<br />
low amplitude error fields in a fusion reactor. The stabilization<br />
of NTMs by RF current in the presence of a static helical<br />
field was therefore further investigated. The applied helical<br />
field allows controlling the location of the island’s o-point<br />
to be in the RF wave deposition region, to enable the NTM<br />
stabilization by RF current after mode locking. When the<br />
island is large enough to be locked by a small amplitude helical<br />
field in the desired phase, the island is reduced to a<br />
smaller width by RF current compared to the case without<br />
the helical field. This suggests a possible way to enhance the<br />
stabilization of NTMs by RF current.<br />
The error field (or externally applied helical field) penetration<br />
was studied numerically based on the two fluids equations.<br />
It was shown that there is a minimum in the required<br />
field amplitude when the applied helical field frequency is<br />
the same as the mode frequency being determined by both<br />
the background equilibrium plasma rotation and the diamagnetic<br />
drift. The mode penetration threshold significantly<br />
increases as the field frequency deviates from the mode frequency<br />
and can become asymmetric on both sides of the<br />
minimum due to parallel transport. After mode penetration,<br />
the non-linear saturated island width is found to be smaller<br />
for larger electron diamagnetic drift frequencies.<br />
Transport Analysis Group<br />
In the field of core transport, work has been dedicated to<br />
understanding the central behaviour of Si laser ablated impurities<br />
in response to localized central electron heating in<br />
AUG H-mode plasmas with a background of NBI heating.<br />
The Si impurity central profile flattens in response to central<br />
electron heating up to exhibiting a hollow profile which cannot<br />
be explained by neoclassical theory. The gyrokinetic<br />
code GS2 has been used to calculate the turbulent transport<br />
of the Si impurity under these experimental conditions.<br />
It has been found that in the presence of strong central electron<br />
heating, modes rotating in the electron diamagnetic drift<br />
direction are destabilized in the central region of the plasma,<br />
generated by the non-adiabatic response of passing electrons<br />
and featuring extremely elongated eigenfunctions along<br />
the field lines. The related fluctuations in the electrostatic
potential generate an outward convection of the impurities<br />
which is in agreement with the outward convection of Si<br />
measured under these experimental conditions. By contrast,<br />
in the outer region of the plasma, as well as everywhere in<br />
the absence of central electron heating, ion temperature gradient<br />
modes produce an inward impurity pinch, which is<br />
also in agreement with experimental observations.<br />
In the framework of transport modelling, simulations of<br />
ITER and DEMO scenarios have been continued. The question<br />
which has been answered is whether a theory-based transport<br />
simulation can be characterized by a fixed enhancement<br />
factor with respect to the H98(y,2) confinement scaling.<br />
It is found that although a noticeable concurrence is observed,<br />
this is no more than an occasional coincidence. The<br />
scaling and theory-based predictions show very different<br />
parameter dependences and there is no simple recipe to<br />
replace one by the other. During this work, a new numerical<br />
algorithm has been developed that allows for an increase of<br />
the speed of computations by orders of magnitude and<br />
enables massive parametric studies with theory-based stiff<br />
transport models.<br />
Kinetic Theory and Wave Physics Group<br />
We have completed the implementation of a realistic NBI<br />
source in the SSFPQL Fokker-<strong>Planck</strong> solver embedded in<br />
the TORIC package. This was motivated by ASDEX<br />
Upgrade experiments, suggesting a 2 nd -harmonic heating of<br />
NBI deuterons in the neutron rate time trace. We have<br />
improved the algorithms and added toroidal effects on the<br />
RF quasi-linear operator.<br />
To close the consistency loop between the TORIC full-wave<br />
solver and the Fokker-<strong>Planck</strong> module, we have started to<br />
modify the interface for the evaluation of the coefficients of<br />
the wave equation in the presence of non-<strong>Max</strong>wellian distribution<br />
functions.<br />
We have updated and optimized the full-wave code FELHS<br />
for lower hybrid (LH) waves in slab geometry. This code<br />
estimates the grill coupling efficiency for general density<br />
and magnetic field profiles. It is currently used by the POLITO<br />
group (Torino, Italy) to obtain the plasma response in their<br />
antenna code for the evaluation of the coupling efficiency of<br />
LH launchers.<br />
The propagation of LH waves in toroidal plasmas can be<br />
computed employing the beam tracing technique, which reduces<br />
the wave equation to a set of ordinary differential<br />
equations (thus reducing the computational effort) retaining<br />
diffraction effects. The diffractive broadening of the beam<br />
is believed to provide a mechanism for filling the spectral<br />
gap between the electron thermal velocity and the phase<br />
velocity of the wave. To this aim, the code LHBEAM has<br />
been developed. It solves the beam tracing equations in<br />
tokamak geometry for arbitrary launching conditions and<br />
for analytic magnetic equilibria. First results show a signifi-<br />
Theoretical Plasma Physics<br />
83<br />
cant broadening of the LH beam for parameters typical of<br />
present-day experiments. The evaluation of the resulting<br />
wave-number spectrum is under way.<br />
The expulsion of fast trapped ions generated during IC heated<br />
discharges has been investigated. Losses of energetic particles<br />
with gyroradii above 4 cm have recently been observed<br />
in ASDEX Upgrade and have been shown to be related to<br />
low-frequency MHD modes like NTMs.<br />
The loss mechanism is found to be connected to the drift of<br />
the ions along the perturbed magnetic field, which acquires<br />
a preferential radial direction if the bounce frequency is close<br />
to a multiple of the toroidal precession frequency. This mechanism<br />
also explains the phase modulation of the particle-loss<br />
signal. Numerical simulations performed with the HAGIS<br />
code show good agreement with experimental results.<br />
Development of Mathematical Tools<br />
Mathematical models for anomalous transport were considered.<br />
In particular, a quasi-linear heat equation with only<br />
piecewise differentiable coefficients was investigated further.<br />
Existence of solutions with a moving free boundary was<br />
proven under milder assumptions than previously.<br />
Also, matrix-free iteration schemes for the solution of large<br />
non-linear parameter-dependent systems were investigated<br />
further. If Picard iterations cease to converge at a certain<br />
parameter value, it almost always helps to split the solution<br />
manifold: Newton iterations on a small invariant subspace,<br />
Picard iterations on the large remainder.<br />
Turbulence Theory Group<br />
We continue to study low frequency fluid like drift turbulence<br />
employing gyrofluid models extended to capture<br />
important kinetic effects such as Landau damping and finite<br />
gyroradius (FLR), as well as gyrokinetic models, treating all<br />
phenomena at the scales of interest (1 mm to 10 cm, 10 kHz<br />
to 1 MHz). Both types of model have been recast for greater<br />
accuracy within a wider set of parameter regimes. The<br />
gyrofluid model GEM and the gyrokinetic model dFEFI are<br />
intended to treat equilibrium and turbulence phenomena<br />
together at all collisional regimes, as especially needed for<br />
the tokamak edge. The gyrokinetic particle in cell code<br />
ORB5 is intended to treat global core turbulence and will<br />
attempt full-scale ITER simulations in 2008.<br />
Gyrokinetic/Gyrofluid Studies of Core Turbulence<br />
The ORB5 model treats the plasma as a set of marker particles<br />
sampling the phase space on a discrete basis. ORB5 is<br />
one of the codes advancing the state of the art on PIC methods<br />
in global gyrokinetic computation in this decade. Work on<br />
hyperfine scale electron temperature gradient (ETG) turbulence,<br />
occurring at scales below the ion gyroradius, was<br />
completed in 2006 and published in early <strong>2007</strong>. Ion temperature<br />
gradient (ITG) turbulence was the focus for <strong>2007</strong>.
Generally, ITG turbulence is more difficult computationally<br />
because it generates large scale “zonal” flows (“zonal”<br />
refers to the flux surface average component). These flows<br />
represent the perturbed equilibrium and are involved in geodesic<br />
acoustic oscillation “modes” (GAMs). They serve to<br />
moderate the turbulence and represent a long-term background<br />
phenomenon to which the turbulence is coupled.<br />
Hence, runs must be longer and noise and saturation issues<br />
increase the difficulty. In <strong>2007</strong> the massively parallel scaling<br />
properties of the code were improved and it now runs reliably<br />
on at least 10,000 processors. A novel diagnostic to<br />
quantify the noise issues was developed; recent cases are<br />
run to saturation with the noise in the range of 5 percent.<br />
Kinetic electrons have been included. A run on 10 k processors<br />
on the Edinburgh Hector platform found well behaved<br />
long term saturation and converged scale separation<br />
(between turbulence and profile relaxation). In 2008 the<br />
Alfvén dynamics will be tested and full scale ITER cases<br />
will be run.<br />
Global electromagnetic computations of ITG/Alfvén turbulence<br />
were run using GEM for various tokamak sizes.<br />
For domain sizes of at least 200 ion gyroradii complete<br />
scale separation was found: the turbulence no longer has<br />
any effect on the profile of poloidal (specifically, E×B)<br />
rotation. The rotation profile is determined by neoclassical<br />
effects (balances between parallel forces/divergences and<br />
magnetic drifts). For JET and ITER scale (400 or 800 gyroradii)<br />
even the details of the profile shape change only on<br />
transport time scales. In the course of this work the GEM<br />
code was improved so as to scale to 512 processors on the<br />
IBM Regatta architecture at well over 80 percent efficiency<br />
Theoretical Plasma Physics<br />
84<br />
in the hard scaling. Similar performance up to 2048 processors<br />
on the new Blue GENE/P was achieved.<br />
Gyrofluid/Gyrokinetic Studies of Edge Turbulence<br />
The study of self consistent geometry up to now requires<br />
analytical models for the metric. Changes in the q-profile<br />
and the Shafranov shift due to the background currents and<br />
pressure profile are followed. This model was extended to<br />
include proper separatrix geometry, which will be incorporated<br />
into the GEM code.<br />
Several series of parameter scalings were run using both<br />
GEM and dFEFI in fluxtube mode (radially local gyrofluid<br />
and phase space gyrokinetic treatments of the same problem<br />
set) to test hypotheses involving temperature scaling of<br />
sheared equilibrium E×B rotation and turbulence. A weak<br />
dependence of shear suppression on temperature and flow<br />
shear was found, but too weak to overcome the larger ρ ∗ at<br />
higher temperatures.<br />
The ideal MHD instability scenario for ELM events was<br />
investigated using GEM. In contrast to other studies using<br />
MHD models, GEM also treats the generic drift wave turbulence<br />
down to and below the ion gyroradius scale. No threshold<br />
was found because the turbulence remains driven by<br />
temperature gradients (both species) when the ideal ballooning<br />
instability is absent. The transition to MHD dominance<br />
is gradual. Converged cases are found only when the spectrum<br />
reaches all the way down to the ion gyroradius. The time<br />
scale and energy content of the blowout are commensurate<br />
with experimental observations, but the scenario remains a<br />
hypothesis because clearly self consistent representations<br />
of the H-mode state are still lacking.<br />
Figure 1: Electron density contours before, during, and after an ideal ballooning mode blowout. The original instability has toroidal mode numbers 7-9, visible at<br />
the beginning of the event. The blowout eventually saturates upon its own self-generated turbulence, whose scale range reaches down to the ion gyroradius.<br />
Work carried out in collaboration with A Kendl, Uni Innsbruck.
Fundamental Theory<br />
The proper form of magnetic non-linearities in gyrofluid<br />
equations which treat electron gyroradius effects was<br />
worked out. These equations can be used for reconnection<br />
studies which involve non-linearly generated current sheets<br />
on the plasma skin depth and electron gyroradius scales.<br />
The complete derivation of the reduced MHD equations<br />
from fully non-linear (“total-f”) gyrokinetic field theory was<br />
worked out. Improved numerical schemes using this as a<br />
splitting method are under investigation.<br />
EU-Task Force on Integrated Modelling<br />
We are participating intensively in the turbulence benchmarking<br />
projects under the auspices of the EU Task Force<br />
on Integrated Tokamak Modelling. B Scott is the Project 4<br />
leader.<br />
Scientific Staff<br />
C. Angioni, A. Bergmann, R. Bilato, A. Bottino, M. Brüdgam,<br />
A. Chankin, D. Coster, A. Dodhy-Würsching, S. Gori,<br />
S. Günter, M. Hölzl, O. Kardaun, H.-J. Klingshirn, C. Konz,<br />
K. Lackner, P. Lauber, P. Martin, P. Merkel, R. Meyer-<br />
Spasche, G. Pautasso, G. Pereverzev, E. Poli, T. Ribeiro,<br />
W. Schneider, E. Schwarz, B. Scott, M. Sempf, M. Siccinio,<br />
H. Siddiqui, E. Strumberger, C. Tichmann, C. Wigger, Q. Yu,<br />
R. Zille.<br />
Guests<br />
C. V. Atanasiu, <strong>Institut</strong>e of Atomic Physics, Bukarest, RO;<br />
N. Bertelli, University of Pavia, IT; O. Maj, University of Pavia,<br />
IT; P. McCarthy, University College, Cork, IR; G. J. Miron,<br />
<strong>Institut</strong>e of Atomic Physics, Bukarest, RO; E. Quigley, University<br />
College, Cork, IR; V. Rozhansky, Technical University,<br />
St. Petersburg, RU; G. Sias, RFX Consorzio, IT;<br />
G. N. Throumoulopoulos, University of Ioannina, GR;<br />
S. Voskoboynikov, Technical University, St. Petersburg, RU;<br />
H. Weitzner, Courant <strong>Institut</strong>e, New York, USA.<br />
Theoretical Plasma Physics<br />
85<br />
Stellarator Theory Division<br />
Head: Prof. Dr. Per Helander<br />
During <strong>2007</strong>, Jürgen Nührenberg retired from his post as head<br />
of the Stellarator Theory Division, and the W7-X Applied<br />
Theory Group was incorporated into the Division.<br />
ITG Turbulence Simulations<br />
Ion-temperature-gradient turbulence constitutes a possibly<br />
dominant transport mechanism in optimized stellarators, at<br />
least in some regions, in view of the effective suppression<br />
of neoclassical losses characterizing these devices. The gyrokinetic<br />
code GENE has been extended to work in general<br />
geometry and nonlinear turbulence simulations for W7-X<br />
have been performed, assuming an adiabatic electron response.<br />
Several interesting results have been found, including<br />
the role of zonal flows for turbulence saturation, the<br />
resulting flux-gradient relationship, and the coexistence of<br />
ion-temperature-gradient modes with trapped ion modes in<br />
the saturated state.<br />
Global Gyrokinetic Simulations<br />
The particle-in-cell code EUTERPE which is used for the<br />
global simulation of linear ITG modes in stellarator geometry<br />
has been extended to allow for the inclusion of density gradients.<br />
Since a radial electric field can also be prescribed it<br />
is now possible to run simulations under realistic conditions.<br />
When the electron response is adiabatic the equation for the<br />
electric field consists of a Helmholtz operator plus a nonlocal<br />
term given by the flux surface average of the electrostatic<br />
potential. This term is important to correctly capture<br />
the behaviour of zonal flows which are important for nonlinear<br />
simulations. While the matrix representation of the<br />
Helmholtz operator is sparse that of the averaging operator<br />
leads to a dense matrix. To overcome the related memory<br />
problems a new solver has been developed which treats the<br />
non-local term as matrix-free in the context of preconditioned<br />
iterative solver methods. As an application for this<br />
new solver the Rosenbluth-Hinton test was performed for<br />
tokamak configurations with different aspect ratio and elongation.<br />
It was found that the residual flow level increases<br />
with increasing elongation or decreasing aspect ratio in<br />
good agreement with semi-analytical theory. To perform<br />
global simulations of turbulence, a non-linear version of<br />
EUTERPE has been developed. Scalability has been demonstrated<br />
for up to 512 processors, which is a prerequisite for<br />
non-linear simulations.<br />
Plasma Rotation in Stellarators<br />
The conditions were investigated under which rotation<br />
comparable to the ion thermal speed may occur in threedimensional<br />
equilibria. For tokamaks, it is well known that<br />
the plasma can rotate toroidally but not poloidally if the ion
gyro-radius is small. The corresponding question for stellarators<br />
had, however, not been answered. It turns out that<br />
rapid plasma rotation is only possible in a certain class of<br />
magnetic fields where the magnetic field strength depends<br />
on the arc length along the field in the same way for every<br />
field line on the same flux surface. In particular, quasiaxisymmetric<br />
and quasi-helically symmetric magnetic<br />
fields fulfil this condition. Moreover, the plasma flow must<br />
be in the direction of constant magnetic field and tangential<br />
to the flux surfaces.<br />
Resistive Stability in Plasmas with Runaway Electrons<br />
In tokamak disruptions, the Ohmic current is often replaced<br />
by a current of runaway electrons which is likely to be<br />
peaked more strongly in the centre of the discharge than the<br />
pre-disruptive current. This raises the question of the resistive<br />
stability of the post-disruption plasma where the equilibrium<br />
current is entirely carried by the runaway electrons<br />
while the cold (
as the background magnetic field the Alfvén continuum<br />
frequency can lie in the range of the diamagnetic frequency<br />
of the background electrons. If the electron diamagnetic<br />
frequency exceeds the mode frequency an unstable drift-<br />
Alfvén wave arises due to the coupling between the drift<br />
and Alfvén waves. The coupling occurs through the parallel<br />
electric field and the mode is destabilized due to parallel<br />
resonances such that this phenomenon can be described in<br />
screw pinch geometry. Since the mode is non-perturbative<br />
its growth rate can be large and comparable to the real part<br />
of the mode frequency. The growth rate usually attains its<br />
maximum at a small mode number such that the most<br />
unstable mode can appear to be global and may be confused<br />
with, e.g., a global Alfvén mode (GAE).<br />
Ideal MHD<br />
The ideal MHD stability code CAS3D was generalized to<br />
be used for the calculation of a perturbed equilibrium<br />
which is provided by the linear ideal stability theory as the<br />
plasma response to a small perturbation of an equilibrium<br />
state. In this approach magnetic islands may be characterized<br />
by a surface current. The CAS3D results were successfully<br />
benchmarked vs. a code for the ideal cylindrical stability.<br />
In stellarator geometry, the shift of the magnetic<br />
surfaces due to a plasma-beta increase, computed by<br />
CAS3D, compares well to results gained from the VMEC<br />
equilibrium code.<br />
Kinetic MHD<br />
The CKA code (to calculate Kinetic Alfvén waves in stellarators)<br />
has been further developed and benchmarked. It<br />
employs a reduced MHD model with finite Larmor radius<br />
effects. So far, relatively good agreement with ideal MHD<br />
has been achieved. To allow the calculation of fast particle<br />
interaction with waves a reorganisation of the CAS3D-K<br />
code has begun. In its new structure the code has been<br />
applied to zonal flow physics.<br />
Development of Stellarator Concept<br />
In quasi-isodynamic configurations, the divergence of the<br />
current density perpendicular to the magnetic field lines<br />
changes sign only once along the magnetic field within one<br />
field period. This implies that the parallel current density<br />
cannot change sign along the magnetic field. Thus, because<br />
of the vanishing net parallel current, the parallel current<br />
density exhibits a dipole component which impairs MHD<br />
stability at very high-β. In this work, a new structure of a<br />
period has therefore been introduced in which the B contours<br />
change their inclination with respect to the orthogonals<br />
to the field lines along the magnetic field within half a<br />
period. This makes it possible to eliminate the dipole component<br />
of the parallel current density whilst keeping the second<br />
adiabatic invariant constant.<br />
Theoretical Plasma Physics<br />
87<br />
Applied Theory Group<br />
Bootstrap Current Benchmarking<br />
In the benchmarking of mono-energetic bootstrap current<br />
coefficients, two different Monte Carlo codes (VENUS-δf,<br />
NEO-MC), the drift kinetic equation solver (DKES), and a<br />
fieldline integration technique (NEO-2) have been applied<br />
for the standard configurations of LHD (classical stellarator),<br />
NCSX (quasi-axisymmetric) and W7-X (minimized bootstrap<br />
current). Very reasonable agreement of these codes for<br />
the three configurations has been obtained. This work is part<br />
of the International Collaboration on Neoclassical Transport<br />
in Stellarators.<br />
Consequences of Assuming Incompressible ExB Drift in<br />
Neoclassical Transport Theory<br />
The conventional “local ordering” assumptions made in the<br />
theory of neoclassical stellarator transport to derive the linearized<br />
drift kinetic equation decrease the number of variables<br />
in the problem by two, with both the flux-surface label<br />
and kinetic energy becoming mere parameters. To express<br />
the resulting mono-energetic kinetic equation in conservative<br />
form requires that the E×B drift within the flux surface<br />
be assumed incompressible. The validity of this assumption<br />
has been investigated by using a δf Monte Carlo code to<br />
solve the local kinetic equation with the option of retaining<br />
the kinetic energy as a variable. Results indicate that the<br />
assumption of incompressible E×B drift is appropriate as<br />
long as this drift is not large enough to compete with the<br />
poloidal component of a particle’s drift along the field line.<br />
When this “resonance” condition is reached, mono-energetic<br />
solutions of the kinetic equation significantly underestimate<br />
the resulting neoclassical transport.<br />
Correction of Neoclassical Fluxes to Satisfy Momentum<br />
Conservation<br />
Following the method of Taguchi (Phys. Fluids B 4 (1982)<br />
3638), solutions of the mono-energetic drift kinetic equation<br />
employing the Lorentz (pitch-angle scattering) collision<br />
operator have been corrected so that the flux surface averaged<br />
neoclassical fluxes, determined from them satisfy parallel<br />
momentum conservation for a multi-species plasma. As<br />
expected from physical considerations, calculations of the<br />
parallel electrical conductivity are strongly affected by this<br />
momentum correction but changes in the radial particle and<br />
energy fluxes are negligible at reactor relevant collisionalities.<br />
The bootstrap current is significantly reduced in pure<br />
ion-electron plasmas (by roughly a factor of two in W7-X)<br />
but rapidly approaches its uncorrected level as the effective<br />
charge state is increased by the introduction of impurities.<br />
Predictive and Analysis Transport Code<br />
Transport simulations for different W7-X magnetic configurations<br />
and heating scenarios have been continued to extend
the reference profile database. The neoclassical transport<br />
simulations for W7-X are based on the DKES database of<br />
mono-energetic transport coefficients for the low-mirror, the<br />
standard, and the high-mirror configurations with ι(a)=1.<br />
Here, the standard configuration has the lowest neoclassical<br />
transport which is further reduced with increasing β (whereas<br />
the bootstrap current increases with β). The high-mirror<br />
configuration fulfils the optimisation criterion of minimized<br />
bootstrap current as long as “electron-root” scenarios are<br />
avoided, although the bootstrap current is also expected to<br />
increase with β (due to reduction of the toroidal mirror term).<br />
The ray-tracing code TRAVIS has been included as a module<br />
in the transport code to self-consistently simulate modifications<br />
of electron cyclotron resonance heating (ECRH), noninductive<br />
current drive, and plasma profiles. The upgraded<br />
codes can now handle multi-beam heating schemes with reflection<br />
from mirrors and the vacuum vessel which is especially<br />
important for O2 (second harmonic of the ordinary mode)<br />
and X3 (third harmonic of the extraordinary mode) scenarios<br />
with incomplete first-pass absorption of the ECRH power.<br />
Transport Simulations of High-Power O2 Heating in W7-X<br />
ECRH at densities as high as 2×10 20 m -3 is envisaged for<br />
W7-X at the second harmonic of the ordinary mode (O2).<br />
First-pass absorption of O2 ECRH is relatively poor for the<br />
projected plasma parameters, enforcing the adoption of a<br />
multi-pass absorption scheme with a fixed launching geometry<br />
to conform with the placement of mirrors and reflecting<br />
surfaces within the vacuum vessel. Using the transport/raytracing<br />
package, this scheme is predicted to deliver threepass<br />
absorption in excess of 95 % and produce plasmas with<br />
〈β〉≈4 % for 10 MW of ECRH power. For such simulations,<br />
the combination of Shafranov shift and diamagnetic effect<br />
moves the ECRH deposition zone significantly inwards<br />
which is most easily counteracted by increasing the initial<br />
strength of B by several percent.<br />
ITER Benchmark of the Ray-Tracing Code TRAVIS<br />
A successful benchmark with the reference scenario 2 for<br />
ITER has been performed with the recently developed raytracing<br />
code TRAVIS. In particular, the electron cyclotron current<br />
drive (ECCD) was calculated for both the upper and equatorial<br />
launcher. It has been found that for the range of angles<br />
expected to be optimal for ECCD, accounting for momentum<br />
conservation is mandatory. Additionally, the scenario with<br />
reduced magnetic field has been considered, where it was<br />
found that the ECCD efficiency (as well as the deposition profile)<br />
may be significantly altered for the equatorial launcher<br />
due to unwanted absorption at the higher (parasitic) harmonics.<br />
Divertor Transport Studies for Helical Devices<br />
Transport essentials of the helical divertor in LHD were<br />
investigated and compared to those already intensively studied<br />
Theoretical Plasma Physics<br />
88<br />
for the island divertor of W7-AS, aiming at identifying common<br />
physics issues of two helical devices with completely<br />
different divertor concepts and geometries. For W7-X, a<br />
systematic numerical study of the island screening effect on<br />
recycling neutrals and intrinsic impurities has been started<br />
with the standard island divertor configuration; preliminary<br />
results are being analyzed. The EMC3-EIRENE code is<br />
being implemented for NCSX.<br />
Configuration Studies for W7-X<br />
The configuration space of Wendelstein 7-X has been explored<br />
at large toroidal mirror ratios. These configurations<br />
show worsened interchange stability properties as both<br />
shear and depth of the vacuum magnetic well are reduced so<br />
that most configurations become interchange unstable at<br />
medium to high β values. Another interesting quality is a<br />
further reduction of the parallel current density which completely<br />
suppresses the dipole component of the Pfirsch-<br />
Schlüter currents for mirror fields around 30 %. Configurations<br />
with negligible Shafranov shift at 〈β〉≈10 % can<br />
be found.<br />
Recovery of External Coil Currents for W7-X Vacuum<br />
Configurations<br />
The fast equilibrium reconstruction technique, called function<br />
parametrisation (FP), was applied, indirectly, to recover<br />
the external coil currents of W7-X in an inverse transformation.<br />
The “inversion” is in the mapping of (known or<br />
pre-determined) physical parameters of a configuration<br />
onto the coil currents. The importance of this lies in the<br />
fact that it serves to answer queries on the feasibility of<br />
desired configurations with respect to allowed values of<br />
external currents, something very crucial during the operation<br />
of stellarators. The method employs an iterative minimisation<br />
of target functions using the FP with the coil currents<br />
as independent parameters since direct inversion is<br />
not possible.<br />
Scientific Staff<br />
C. D. Beidler, M. Borchardt, S. Braun, M. Drevlak, D. Eremin,<br />
Y. Feng, J. Geiger; P. Helander, K. Kauffmann, R. Kleiber,<br />
A. Könies, H. Maaßberg, N. Marushchenko, A. Mishchenko,<br />
C. Nührenberg, J. Nührenberg, J. Riemann, A. Runov, F. Sardei,<br />
A. Sengupta, Yu. Turkin, P. Xanthopoulos, X. Zha.<br />
Guests<br />
J. Canic (ORNL), T. Fülöp (TU Chalmers Göteborg),<br />
L. Guazzotto (MIT), M. Kobayashi (NIFS), L. Koziol (USC),<br />
R. Maingi (ORNL), M. Mikhailov (Kurchatov <strong>Institut</strong>e),<br />
D. Mikkelsen (PPPL), A. Simakov (LANL), Z. Unterberg<br />
(DIII-D).
<strong>Max</strong> <strong>Planck</strong> Junior Research Group<br />
“Turbulence in Magnetized Plasmas”<br />
Head: Dr. Wolf-Christian Müller<br />
Turbulent Convection<br />
Turbulence driven by thermal fluctuations around a mean<br />
temperature gradient plays a role in various physical systems<br />
like the Sun, the earth’s atmosphere, and fusion plasmas.<br />
Large scale direct numerical simulations of turbulent convection<br />
in plasmas as well as neutral fluids described in the Boussinesq<br />
approximation were performed using a parallel pseudospectral<br />
code in fully periodic geometry. Two dimensional magnetohydrodynamic<br />
(MHD) convective turbulence shows self-excited<br />
quasi-oscillations between regimes that are either dominated by<br />
buoyancy or by inertial forces depending on the mutual alignment<br />
between velocity and magnetic field. In addition, a simulation of<br />
a three-dimensional hydrodynamic system with 20483 collocation<br />
points has been started, making this simulation the largest<br />
numerical effort in turbulent convection world-wide. To this end,<br />
the numerical code has been highly optimized for the HLRBII<br />
supercomputer at the Leibniz computing centre in Garching.<br />
Lagrangian Statistics of Turbulence<br />
Turbulent transport is a key feature of many physical problems<br />
such as plasma confinement in fusion devices, the turbulent<br />
dynamo, or the propagation of cosmic rays in the interstellar<br />
medium. The diffusive characteristics of turbulence are best<br />
studied from the Lagrangian viewpoint. Lagrangian statistics<br />
of incompressible magnetohydrodynamic turbulence are obtained<br />
by tracking tracer particles in direct numerical simulations.<br />
A full parallelization of the particle tracking scheme has<br />
made it possible to use up to 1024 parallel processes. In MHD<br />
turbulence under the influence of a mean magnetic field turbulent<br />
diffusion and relative dispersion of the tracer particles<br />
has been found to be enhanced in the direction of the mean<br />
magnetic field. The results agree with the picture which has<br />
been developed for macroscopically isotropic MHD turbulence.<br />
Turbulent flows are commonly driven by temperature gradients.<br />
Therefore, Lagrangian tracers have been added to the<br />
large HLRBII-run of convective Navier-Stokes turbulence.<br />
Compressible Turbulence<br />
Within the Cluster of Excellence “Origin and Structure of the<br />
Universe” the efforts to study supersonic turbulence focus on<br />
turbulent dynamics which are probably of importance for starand<br />
structure-formation in the interstellar medium. To this end,<br />
a new numerical framework is being developed to work reliably<br />
on turbulent configurations with Mach numbers greater than<br />
five. Special attention is paid to a low dissipation approach since<br />
thin and sharply resolved shock fronts are a dominant feature<br />
of supersonic turbulence. The new 2D and 3D compressible<br />
MHD codes are able to capture shocks while maintaining the<br />
divergence free constraint on the magnetic field. The underlying<br />
Theoretical Plasma Physics<br />
89<br />
numerical scheme of Kurganov-Tadmor type in combination<br />
with third order CWENO reconstruction is built on central differences<br />
meeting the requirements of low numerical dissipation and<br />
of high precision. The code has been successfully tested for accuracy<br />
and for its shock capturing ability and is currently being parallelized.<br />
The project represents a direct point of contact with astrophysics<br />
groups of the MPA (Hillebrandt) and LMU (Burkert).<br />
Structure Formation in MHD Turbulence<br />
Magnetic helicity quantifies various structural aspects of a<br />
magnetic field. It is important in reversed-field-pinch experiments<br />
as well as in astrophysical plasmas since its dynamics<br />
is believed to be the cause of large scale magnetic structures<br />
accompanying many celestial bodies. We study the associated<br />
inverse cascade, i.e., the self-similar spectral transport from<br />
small scales to large scales by means of direct numerical simulations<br />
of 3D MHD turbulence. Systems with small scale drive<br />
of turbulence and magnetic helicity have been set up resulting<br />
in a clearly established cascade process whose characteristics<br />
are in contradiction to all known theories. Current studies<br />
focus on a more realistic representation of the small scale<br />
dynamics of turbulence to verify this finding. In a complementary<br />
activity, the behaviour of magnetic helicity in decaying<br />
3D MHD turbulence is investigated numerically.<br />
Fundamental Properties of Turbulence<br />
The investigation of anisotropic cascade dynamics in MHD turbulence<br />
permeated by a strong mean magnetic field is continued.<br />
Recent numerical experiments as well as detailed diagnostics<br />
of large scale simulations have led to serious doubts about the<br />
validity of the well-accepted Goldreich-Sridhar picture of anisotropic<br />
turbulence. Further efforts will be necessary to corroborate<br />
this claim. Numerical investigations of the monoscaling property<br />
of probability density functions (PDFs), recently found in the<br />
solar wind, show that this feature is probably a new universal<br />
symmetry of turbulence. We found it in various turbulent MHD<br />
and Navier-Stokes systems for the two-point energy fluctuations.<br />
The PDFs resemble Levy laws of gamma-type ~1/x 1+k exp(-x/x 0 ),<br />
k>0. A newly developed theory in the spirit of polymer fragmentation<br />
models explains the observed behaviour as a consequence<br />
of a turbulent transfer process in spectral space and restricts the<br />
monoscaling property to cascading quantities like energy or density<br />
(in the compressible case). Triad interactions, the fundamental<br />
building blocks of non-linear dynamics in incompressible turbulence,<br />
are studied in 3D Navier-Stokes and MHD-turbulence. After<br />
the necessary diagnostic tool has been developed and successfully<br />
tested on the dual cascade of 2D hydrodynamic turbulence,<br />
the analysis is currently being extended into the third dimension.<br />
Scientific Staff<br />
A. Busse, T. Hertkorn, S. Malapaka, M. Momeni, D. Škandera,<br />
Y. Rammah, Ch. Vogel.
Helmholtz University Research Group<br />
“Theory and Ab Initio Simulation of Plasma Turbulence”<br />
Head: Prof. Dr. Frank Jenko<br />
The main goal of this project (in collaboration with the<br />
<strong>Institut</strong>e for Theoretical Physics at the University of Münster)<br />
is to treat the important unsolved problem of plasma turbulence<br />
in an interdisciplinary way. To this end, we extend and<br />
extend ideas from fluid turbulence, non-linear dynamics, and<br />
statistical physics. Spanning a wide range of approaches,<br />
from simple analytical models to simulations on massively<br />
parallel computers, we strive for a deeper understanding of<br />
the fundamental processes in turbulent magnetoplasmas.<br />
Beyond this, we hope that this project helps to improve the<br />
general dialogue and cross fertilization between plasma<br />
physics and the related fields.<br />
Massively Parallel Gyrokinetic Simulations<br />
The non-linear gyrokinetic continuum code GENE has been<br />
developed during past years. It includes the following effects:<br />
(1) fully kinetic ions and electrons [passing and trapped]<br />
(2) beam ion and impurity species [passive and active]<br />
(3) collisional scattering in pitch angle and energy<br />
(4) electromagnetic effects<br />
(5) general toroidal geometry or simple model equilibria.<br />
Moreover, GENE runs on several parallel platforms and has<br />
been shown to scale almost linearly up to 32,768 processors<br />
on an IBM BlueGene architecture. It is thus suited for high<br />
resolution runs containing most of the physics which is currently<br />
considered important for turbulence and transport in<br />
the core of magnetized fusion plasmas.<br />
Non-linear Saturation of Trapped Electron Modes<br />
While it has been known for many years that ion temperature<br />
gradient (ITG) modes are usually saturated via the nonlinear<br />
generation of zonal flows, we have found a different<br />
behaviour for trapped electron modes – another key driver<br />
of tokamak core turbulence. Recently, several research<br />
groups in the US have confirmed this result. Via non-linear<br />
GENE simulations and careful postprocessing of the simulation<br />
data we have found that the turbulent E×B fluctuations<br />
induce a perpendicular scattering of the particles which may<br />
be described by an additional diffusion term in the basic<br />
equations. Thus, the long wavelength modes causing most<br />
of the transport are damped by small scale vortices. This<br />
explains the similarity of non-linear and linear modes in the<br />
low wavenumber regime. Moreover, we can now construct<br />
refined quasi-linear transport models which describe the<br />
non-linear runs quite well.<br />
Turbulent Transport of Fast Ions<br />
Studies on the interactions of fast ions in the plasma with the<br />
background turbulence were carried out employing both<br />
Theoretical Plasma Physics<br />
90<br />
simple two dimensional models of passive tracers in turbulent<br />
or pseudo-turbulent fields as well as direct three dimensional<br />
simulations with the GENE code. We were able to<br />
show that under certain, rather generic conditions, the diffusivities<br />
of particles up to about 10 times the thermal energy of<br />
the plasma resemble those of the main ions. The underlying<br />
physical mechanisms was identified and explained. This<br />
finding may serve as an explanation of the relative inefficiency<br />
of neutral beam current drive observed in ASDEX<br />
Upgrade under certain conditions.<br />
Turbulence and Transport in the Core of Stellarators<br />
We also conducted GENE simulations of adiabatic ITG turbulence<br />
in the stellarators Wendelstein 7-X and NCSX.<br />
For Wendelstein 7-X, we found that there exist several fundamental<br />
features different from a tokamak, including the<br />
role of zonal flows for turbulence saturation, the resulting<br />
flux-gradient relationship, and the co-existence of ITG<br />
modes with trapped ion modes in the saturated state. The<br />
resulting transport levels are very moderate, indicating low<br />
ion temperature profile stiffness.<br />
In the case of NCSX, we found that zonal flows are not<br />
responsible for the saturation level, and that the normalized<br />
(with respect to the minor radius) ion temperature gradient<br />
for ITG instability is relatively large compared to a tokamak.<br />
The transport levels are again quite moderate. Further<br />
studies along these lines, also for non-adiabatic ITG modes<br />
and trapped electron modes, are currently underway.<br />
Magnetohydrodynamic Dynamos in Spherical Geometry<br />
Employing the non-linear MHD code DYNAMO, we investigated<br />
the effect of turbulent fluctuations on the onset of<br />
dynamo action in spherical geometry. These studies are<br />
closely linked to the present generation of liquid sodium<br />
experiments like the one at the University of Madison at<br />
Wisconsin. For the first time, it could be shown that certain<br />
findings from recent 3D periodic box simulations carry over<br />
to finite size systems. This concerns, in particular, the rise<br />
and saturation of the critical magnetic Reynolds number<br />
with the fluid Reynolds number. However, there are indications<br />
that the underlying mechanisms are different in the<br />
two situations. Detailed analyses of simulation data are supposed<br />
to shed light on these questions and are expected to<br />
indicate ways of lowering the critical magnetic Reynolds<br />
number in actual experiments.<br />
Scientific Staff<br />
T. Görler, T. Hauff, F. Jenko, F. Merz, M. Püschel, K. Reuter.
Helmholtz Junior Research Group<br />
“Computational Material Science”<br />
Head: Dr. Ralf Schneider<br />
The group studies effects on materials in contact with fusion<br />
and low-temperature plasmas. The major objective is the<br />
development and application of computational physics tools.<br />
Development of a Multi-scale Model for the Interaction of<br />
Hydrogen with Graphite<br />
The multi-scale model was extended further by including the<br />
formation and destruction of hydrogen molecules and the chemical<br />
reactions between hydrocarbons and hydrogen (Küppers-<br />
Hopf cycle). The model has been applied to study hydrogen<br />
retention and release from deposits collected from the leading<br />
edge of the neutralizer of Tore Supra. The simulations showed<br />
that the macropores play the dominant role in the retention and<br />
release behavior of hydrogen. The hydrogen released from<br />
the micropores and mesopores is adsorbed on the surfaces of<br />
the macropores. This internal deposition of hydrogen increases<br />
the tritium retention problem for carbon in a fusion reactor.<br />
Atomistic Description of the Plasma-wall Interaction using Ab<br />
Initio Methods<br />
Highly accurate global potential energy surfaces for C2H +<br />
3 and<br />
C2H +<br />
5 were generated using cluster expansions. They agree<br />
well with spectroscopic frequencies within several cm-1 .<br />
Density Functional Theory methods were applied to study<br />
the diffusion of atomic hydrogen trapped within crystalline<br />
graphite. The ab initio molecular dynamics calculations at<br />
10 K and 300 K show that the H atom forms a chemical bond<br />
with one of the C atoms in graphite. At these temperatures<br />
the H atom is not able to overcome the barrier and thus is<br />
not able to diffuse. These results drastically differ from<br />
those obtained by the use of the empirical Brenner potential<br />
where the H atom is able to diffuse freely. The potential<br />
energy curves calculated using the Brenner potential show a<br />
flat potential in the central region between graphite planes<br />
whereas for DFT calculations a higher potential energy<br />
region between the two planes is observed due to the contribution<br />
from the non-local pseudo-potential energy term.<br />
Kinetic Modelling of Complex Plasmas<br />
Kinetic modelling of plasmas with PIC (Particle-in-Cell)<br />
methods was done in close collaborations with experiments<br />
at the Ernst-Moritz-Arndt University in Greifswald within<br />
the Transregio TR-24 project. Calculation of spatial-temporal<br />
emission profiles in RF-discharges in oxygen including<br />
the formation of negative ions and comparison with experiments<br />
allowed for an estimate of the heavy ion collision<br />
cross-section for dissociative excitation of atomic oxygen<br />
+ by energetic O2 . The oxygen molecular ions get their maximum<br />
energy at the electrode after crossing the sheath.<br />
Theoretical Plasma Physics<br />
91<br />
Figure 4: Distribution of the plasma potential in an azimuthal segment for<br />
quasi steady-state in SPT-100. The fluctuations are clearly visible.<br />
PIC-modelling of electric propulsion Hall thrusters (SPT-100)<br />
demonstrated the importance of secondary electron emission<br />
for the operation of this system: electrons emitted from<br />
the surface of the SPT-100 have lower energies than the<br />
impinging ones. They leave the walls on a different spiral<br />
trajectory which is displaced towards the anode. This creates<br />
a high density low energy layer close to the walls which<br />
increases the electron conductivity strongly in this region.<br />
Another reason for electron cross field transport and axial<br />
currents beyond classical estimates are azimuthal fluctuations,<br />
which were visible in the simulations.<br />
Figure 5: Time evolution of the azimuthal profile of the plasma potential in<br />
the center of the discharge channel. The propagation of the fluctuations<br />
can be seen.<br />
Scientific Staff<br />
K. Matyash, A. Rai, R. Schneider, A.R. Sharma, F. Taccogna.
EURYI Research Group “Zonal Flows”<br />
Head: Priv.-Doz. Dr. Klaus Hallatschek<br />
The project started towards the end of <strong>2007</strong> with the employment<br />
of two doctoral students in November.<br />
The targets for the first year (2008) are a theoretical understanding<br />
of the experimental GAM frequencies and the turbulent<br />
control of the scale length of the zonal flows.<br />
Geodesic Acoustic Mode Studies: Impact of Coupling to Sound<br />
Waves and Turbulence Effect<br />
Analogous to the well known zonal winds in the atmosphere<br />
of gas planets, plasma zonal flows (ZF) are excited<br />
due to the quasi-2D restriction of the turbulence perpendicular<br />
to the magnetic field. Different from the purely 2D<br />
planetary zonal winds, the inhomogeneous magnetic fields<br />
frozen into the moving plasma excite strong flows parallel to<br />
the field as the circulating flux ropes compress or expand to<br />
adjust to the ambient conditions. Depending on the magnetic<br />
geometry, the parallel flow may have the effect of a changed<br />
effective inertia (typically in the tokamak core where the<br />
safety factor is around one) or can be such a strong energy<br />
drain that a stationary flow pattern becomes impossible and<br />
an oscillation between plasma compression and flow results<br />
(usually in the tokamak edge with q~3-5), the Geodesic<br />
Acoustic Mode (GAM). Stationary ZFs and GAMs have<br />
turned out to be a ubiquitous phenomenon in many magnetic<br />
confinement devices (AUG, CHS, H-1, HL-2A, JFT-2M,<br />
Jet, J<strong>IPP</strong>-T2, Textor, TJ-2, T-10). The increasing detail of<br />
the available measurement data on the GAMs allows for a<br />
quantitative comparison with theoretical concepts of the<br />
plasma flows.<br />
In particular, the GAM frequencies in ASDEX Upgrade discharges<br />
with circular flux surfaces1 agreed for low gradients<br />
with the theoretical GAM frequency ωcirc = cs /R, with<br />
κ=5/3 and cs = (see figure 6). However for GAMs at<br />
higher gradients the experimental frequencies were up to a<br />
factor two higher and for elliptic discharges up to a factor<br />
two lower than that.<br />
The down shift of the GAM frequency (neglecting the coupling<br />
to sound waves) for elliptic Miller geometry3 including the<br />
differential Shafranov shift was computed analytically2 2κ<br />
2T/ mi<br />
.<br />
Just using the reconstructed shape of the flux surfaces resulted<br />
in a frequency still about 30 % too high. Including the very<br />
strong differential ellipticity for the respective discharges is<br />
1 th G. D. Conway et al., 34 EPS Conf. on Control. Fusion and Plasma Physics<br />
(Warsaw, Poland) paper O4.009 (<strong>2007</strong>); Conway et al.: “Geodesic acoustic<br />
mode scaling and core localization in ASDEX Upgrade using Doppler<br />
reflectometry”, Plasma Physics and Controlled Fusion, to be published.<br />
2 K. Hallatschek: “Nonlinear three-dimensional flows in magnetized plasmas”,<br />
Plasma Physics and Controlled Fusion 49, B137-B148 (<strong>2007</strong>).<br />
3 R. L. Miller et al.: Physics of Plasmas 5, 973 (1998).<br />
Theoretical Plasma Physics<br />
92<br />
enough to match theoretical and experimental frequencies.<br />
However, the large uncertainties of the reconstruction in the<br />
edge-region require a more detailed survey of data to be<br />
satisfactory.<br />
To facilitate extensive comparisons including the shaping<br />
effects, which are planned for next year, an eigenvalue code<br />
for the computation of GAM frequencies in arbitrary Miller<br />
geometry, including the coupling to parallel sound waves<br />
was written. It turned out, that the presence of the sound<br />
waves typically shifts the GAM frequency by about 20 % –<br />
not enough to be relevant at the current detail level. The<br />
code also yields the hypothesized windows of GAM activity<br />
due to resonances with the sound waves, but will require<br />
accurate flux surface data for a meaningful validation with<br />
the experiment.<br />
The problem of the excess frequencies in case of high gradient<br />
discharges is most likely caused by the turbulence itself. For<br />
once it is possible that the turbulence simply increases the<br />
GAM frequency due to its non-linear interaction 2 . On the<br />
other hand, due to the rapid changes of the plasma parameters<br />
throughout the region with GAM activity, the turbulence<br />
might synchronize the GAM frequency to an area of relatively<br />
high temperature, i.e., high frequency.<br />
Figure 6: From [2]. Measured GAM frequencies (points), and calculated<br />
linear GAM frequencies including sound wave coupling, using a Miller [3]<br />
equilibrium reproducing the parameters R, r, R’, k, k’ of the nominal equilibrium.<br />
Experimental data from [1].<br />
Scientific Staff<br />
N. Gürtler, R. Hager.
Supercomputing and other<br />
Research Fields
Introduction<br />
The Rechenzentrum Garching<br />
(RZG) traditionally provides supercomputing<br />
power and archival<br />
services for the <strong>IPP</strong> and other<br />
<strong>Max</strong> <strong>Planck</strong> <strong>Institut</strong>es throughout<br />
Germany. Besides operation<br />
of the systems, application support<br />
is given to <strong>Max</strong> <strong>Planck</strong> <strong>Institut</strong>es<br />
with high-end computing<br />
needs in fusion research, materials science, astrophysics,<br />
and other fields. Large amounts of experimental data from<br />
the fusion devices of the <strong>IPP</strong>, satellite data of the MPI for<br />
Extraterrestrial Physics (MPE) at the Garching site, and data<br />
from supercomputer simulations are administered and stored<br />
with high lifetimes. In addition, the RZG provides network<br />
and standard services for the <strong>IPP</strong> and part of the other MPIs<br />
at the Garching site. The experimental data acquisition software<br />
development group XDV for both the W7-X fusion<br />
experiment and the current ASDEX Upgrade fusion experiment<br />
operates as part of the RZG.<br />
Furthermore, the RZG is engaged in several large projects in<br />
collaboration with other, partly international scientific institutions.<br />
One of these projects is a bioinformatics project<br />
dealing with genome research, another one the ATLAS project,<br />
which is part of the LHC experiment at CERN. And finally,<br />
the RZG is a member of DEISA, a consortium of the leading<br />
European supercomputing centers supporting the advancements<br />
of computational sciences in Europe. In this project the<br />
RZG holds the task leaderships for global file systems, for the<br />
operation of the distributed infrastructure, for applications<br />
enabling, and for joint research activities in plasma physics and<br />
in materials science. All these projects are based on new software<br />
technologies, among others so-called Grid-Middleware<br />
tools. Since the importance of Grid technology for international<br />
collaborations has significantly increased in recent years,<br />
broad competence has to be established also in this field.<br />
Major Hardware Changes<br />
The supercomputer landscape, consisting of the IBM pSeries<br />
690 based supercomputer and the IBM p575 based cluster of<br />
8-way nodes, has been augmented in September <strong>2007</strong> with an<br />
IBM BlueGene/P system with 8,192 PowerPC@850MHz-based<br />
cores which is especially suited for applications scaling up to<br />
1,024 cores and beyond. Furthermore, a series of Linux clusters<br />
with Intel Xeon and AMD Opteron processors is operated,<br />
which has been further extended in the area of Intel Xeon quadcore<br />
and AMD dual-core Opteron based Linux clusters. Besides<br />
the generally available systems, dedicated compute servers<br />
are operated and maintained for: <strong>IPP</strong>, Fritz-Haber-<strong>Institut</strong>e, MPI<br />
for Astrophysics, MPI for Polymer Research, MPI for Quantum<br />
Computer Center Garching<br />
Head: Dipl.-Inf. Stefan Heinzel<br />
A major task has been the optimization of complex<br />
applications from plasma physics, materials<br />
science and other disciplines. The data acquisition<br />
system of W7-X has been implemented<br />
on a smaller existing device (WEGA) and reaches<br />
its test phase. For the FP6 EU project DEISA,<br />
codes from Plasma Physics (GENE and ORB5)<br />
have been enabled for hyperscaling to make<br />
efficient use of up to 32,000 processors.<br />
95<br />
Developments for High-End Computing<br />
Optics, MPI for Extraterrestrial<br />
Physics, MPI for Biochemistry,<br />
MPI for Chemical Physics of<br />
Solids, MPI for Physics and MPI<br />
for Astronomy. In the mass storage<br />
area, the capacity of the new automated<br />
tape library Sun SL8500<br />
has been extended to 6 PB of<br />
compressed data. Both LTO3 and<br />
LTO2 tape drives are supported.<br />
The application group of the RZG gives support in the field of<br />
high-performance computing. This includes supervising the<br />
start-up of new parallel codes, giving advice in case of software<br />
and performance problems as well as providing development<br />
software for the different platforms. One of the major<br />
tasks, however, is the optimization of complex codes from<br />
plasma physics, materials sciences and other disciplines on the<br />
respective, in general parallel high-performance target architecture.<br />
This requires a deep understanding and algorithmic<br />
knowledge and is usually done in close collaboration with<br />
the authors from the respective disciplines. In what follows<br />
selected optimization projects are presented in more detail.<br />
GEM Code<br />
The GEM (Gyrofluid-ElectroMagnetic) code from the <strong>IPP</strong><br />
plasma theory solves nonlinear gyrofluid equations for electrons<br />
and one or more ion species in tokamak geometry. It is<br />
restricted to a local approach in geometry, a so-called fluxtube<br />
approach. According to the parallelization concept of<br />
one-dimensional domain decomposition along the magnetic<br />
field the maximum number of processors to be used was 16.<br />
The new code version GEMR treats the full geometry in the<br />
radial x-direction. Hence, more realistic simulations of turbulence<br />
in experiments like JET and ITER are now in progress.<br />
However, the necessary grid resolution of at least 1024×512×16<br />
is already far too large to be run on just 16 processors.<br />
Correspondingly, the scaling properties of the GEMR code<br />
had to be improved towards many hundreds of processors.<br />
After the single-processor performance had been increased<br />
by 50 %, the parallelization concept was expanded to a twodimensional<br />
domain decomposition by additionally parallelizing<br />
along the x-coordinate. For this purpose the index structure<br />
of the most important arrays had to be adapted to avoid<br />
unnecessary copying in connection with communication. The<br />
parallelization of the matrix solver in x-direction was a nontrivial<br />
task which could finally be solved with an elaborated<br />
parallel transpose of the data and corresponding matrices.<br />
As a result, the scalability could be increased by the envisaged<br />
factor of 32; a parallel efficiency of 89 % from 64 to 512<br />
processors could be observed. Hence, both the distributed
memory and compute power of 512 IBM Power 4 processors<br />
of the “Regatta” high-performance computer at RZG<br />
can be used now to perform simulations of JET and ITER<br />
configurations with the GEMR code.<br />
GENE Code<br />
The GENE code from the <strong>IPP</strong> plasma theory is a so-called<br />
continuum or Vlasov code for turbulence simulations. Nonlinear<br />
gyrokinetic equations are solved on a fixed grid in fivedimensional<br />
phase space. All differential operators in phase<br />
space are discretised by fourth-order (compact) finite differences.<br />
GENE can deal with arbitrary toroidal geometry (tokamaks<br />
or stellarators) and retains full ion/electron dynamics as<br />
well as magnetic field fluctuations. At present, GENE is the<br />
only plasma turbulence code in Europe with such capabilities.<br />
The version 10 of the GENE code, which was already a parallel<br />
hybrid code using both OpenMP (for usage within an SMP) and<br />
MPI (for usage across SMP nodes), was further enhanced by<br />
adding new functionality and parallelizing additionally with<br />
respect to the parallel velocity by applying domain decomposition<br />
techniques. The new version 11 is now scaling up to<br />
several thousands of processors. Tests on an IBM BlueGene/L<br />
at IBM Watson Research Center showed quasi-linear strong<br />
scaling from 1,024 up to 16,384 processors (see figure 1). A<br />
parallel efficiency of 99 % on 32,768 processors for the case<br />
of weak scaling clearly demonstrates the capability of the<br />
newest GENE version for efficient usage on between 10 4 and<br />
10 5 processors of a scalable supercomputing architecture.<br />
speedup<br />
16<br />
14<br />
12<br />
10<br />
8<br />
6<br />
4<br />
2<br />
0<br />
0 5000 10000 15000 20000<br />
number of processors<br />
ORB5 Code<br />
The particle-in-cell code ORB5 from the <strong>IPP</strong> plasma theory<br />
is able to simulate plasmas of high complexity and has high<br />
relevance for ITER. Special effort was given to the ORB5<br />
code to enable it to run with high scalability on thousands of<br />
processors. Benchmarks showed good strong scaling properties<br />
for different test cases up to 8192 processors and a<br />
parallel efficiency of 88 % on an IBM BlueGene/L at the<br />
IBM Watson Research Center.<br />
Computer Center Garching<br />
96<br />
Massive Data Visualization<br />
Since the beginning of 2006, the RZG engages in the visualization<br />
of large datasets as typically produced by scientific<br />
simulation programs. A dedicated visualization workstation is<br />
used, which was purchased by the MPI for Astrophysics. On<br />
this machine a so-called particle-cloud algorithm was implemented<br />
and successfully applied to the massive output of the<br />
millennium simulation by Volker Springel from the MPA. A<br />
special feature of the program in combination with the fast<br />
machine is that the user can interactively fly through the dataset.<br />
Based on this experience a similar method has been implemented<br />
to visualize plasma flux with datasets produced by the<br />
GENE code from the turbulence group of the <strong>IPP</strong> plasma theory.<br />
As the visualization method is independent of the geometry,<br />
it is applicable to datasets of both tokamaks and stellarators.<br />
In close cooperation with M. Püschel, a Java program<br />
has been developed that allows to interactively view a complete<br />
rendering of the plasma (half-) torus or part of the stellarator.<br />
This has been achieved using a hardware-accelerated<br />
point-based plasma rendering. Over 20 Million points can be<br />
handled interactively on the visualization workstation. As the<br />
geometry of the simulated plasma does not change, it was<br />
possible to animate the plasma turbulence; moreover, the<br />
physicist can interactively change the viewpoint and alter the<br />
point size together with a brightness value. Thus different<br />
structures in the dataset can be enhanced (see figure 2).<br />
Figure 1: Strong scaling of GENEv11 for a small problem size (300-500 GB)<br />
on a BlueGene/L machine at IBM Watson Research Center (measurements<br />
in co-processor mode) Figure 2: Snapshot of the visualization program developed for the GENE<br />
code showing a quarter of a half-torus from a tokamak dataset and some<br />
elements to control viewpoint and presentation parameters<br />
The Munich-ATLAS-Tier2 project<br />
Collaborating research groups from the <strong>Max</strong> <strong>Planck</strong><br />
<strong>Institut</strong>e of Physics (MPP) and from the Ludwig <strong>Max</strong>imilian<br />
University (LMU) play a significant role in the ATLAS project<br />
of the Large-Hadron-Collider (LHC) experiment at the<br />
international European Centre for Particle Physics (Cern).
ATLAS is one particular detector, which will provide huge<br />
amounts of data from 2008 on, and many institutes all over<br />
the world consider working with these data. In order to make<br />
this feasible, a hierarchical network of so-called Tier centres<br />
has been established, by which the data is shared and replicated<br />
in a reasonable fashion and the workload is distributed<br />
to the centres.<br />
In Munich, a Tier2 centre was set up by the MPP, the Physics<br />
department of the LMU and the associated computing centres<br />
LRZ and RZG. The tasks of a Tier2 centre are to provide a<br />
certain amount of compute and memory resources, which are<br />
placed at the disposal of all sites taking part in the WLCG<br />
(world-wide LHC Computing Grid) community, and to establish<br />
sufficient memory bandwidth and services for the data<br />
exchange with the associated Tier1 centre. Furthermore, the<br />
Tier2 centre has to provide and support a so-called Gridmiddleware<br />
system, which enables all partners in the WLCG<br />
to access and use the mutual resources.<br />
Bioinformatics/Computational Biology<br />
Within an interdisciplinary consortium joined by several<br />
<strong>Max</strong> <strong>Planck</strong> <strong>Institut</strong>es, the RZG has established a soft and<br />
hardware infrastructure for computational-biology applications<br />
called MIGenAS (<strong>Max</strong> <strong>Planck</strong> Integrated Gene Analysis<br />
System). Generally speaking, this environment allows integrated<br />
access to all relevant software tools and biological<br />
data which are required for comprehensive analyses of biological<br />
systems and mediates transparent access to the underlying<br />
computing resources operated by the RZG. With the<br />
help of two scientific positions provided by the <strong>Max</strong> <strong>Planck</strong><br />
Society, the RZG hosts various bioinformatics services for<br />
project-internal and public use, offers application support<br />
for bioinformatics projects of the <strong>Max</strong> <strong>Planck</strong> Society, contributes<br />
original software development and also participates<br />
in various research projects.<br />
Currently we are, for example, involved in a number of computationally<br />
challenging analyses which are emerging from<br />
so-called metagenomics projects: Thanks to the latest generation<br />
of high-throughput sequencing technology, huge amounts<br />
of DNA sequence data can nowadays efficiently be recovered<br />
from all kinds of environmental samples. Comparing<br />
such DNA sequence data with large databases of annotated<br />
sequences allows one to assign species information to the<br />
unknown sequences and thus gain insights into the biodiversity<br />
of the corresponding habitat. Given the amount of<br />
sequence data to be processed and the size of the relevant<br />
databases to compare with, thorough optimizations of the<br />
corresponding computations have become indispensable. To<br />
this end, a systematic survey of existing algorithms and their<br />
implementation in software was conducted in the context of<br />
a Diploma thesis (H. Zimmerer) supervised jointly with<br />
Prof. D. Huson (University of Tübingen).<br />
Computer Center Garching<br />
97<br />
Concerning bioinformatics software development work has<br />
been focused on the reimplementation and functional extension<br />
of HaloLex, which is a software system for the central<br />
management, integration, curation, and web-based visualization<br />
of genomic and other related “omics” experimental<br />
data (e.g. proteomics) for micro-organisms. The reimplementation<br />
of HaloLex is based on modern software technology<br />
and is being performed in close collaboration with the<br />
original authors (Dept. Oesterhelt, MPI of Biochemistry).<br />
Meanwhile, the system is capable of efficiently handling<br />
data for any given micro-organism and the new web portal<br />
(www.halolex.mpg.de) is already being used by different collaborations<br />
in production for data curation of various genomes.<br />
Videoconferencing (VC)<br />
The VC infrastructure load surpassed the 2006 level. The<br />
total conference time increased to 7152 h, that is about 30 %<br />
plus compared to 2006. The Gatekeeper worked without<br />
breakdowns, with some scheduled shut-downs due to power<br />
supply work. The number of registered endpoints increased<br />
to 350, a plus of 40 %. Conferences with presentation sharing<br />
have become standard. The new Codian MCUs of the<br />
DFNVC Service delivered a very reliable and high-quality<br />
performance; about 30 % of all calls are multi-point. The<br />
new booking system covering 28 rooms (8 VC rooms in<br />
Garching, 6 in Greifswald, 14 non VC meeting rooms) has<br />
been accepted throughout both sites. In 2006 there have<br />
been 2123 bookings (the system was implemented in July<br />
2006), in <strong>2007</strong> the number was 10767 equivalent to an average<br />
1.5 bookings/room/working day. Several test and beta<br />
installations have been done, including a new web-based<br />
calendar and Microsoft’s Office Communicator and its coupling<br />
to the VC standard H.323 via an MCU.<br />
Data Networking<br />
<strong>IPP</strong>’s data network infrastructure was planned with a<br />
cabling structure in mind that can easily be adapted to future<br />
technologies. The network realized is therefore based on the<br />
concept of a “collapsed backbone”, consisting of high-level<br />
switches at a few central locations which directly connect to<br />
all endpoints via links based on copper or fibre – eliminating<br />
the need of limiting switches at workgroup or story level.<br />
With this structure we greatly improved overall network<br />
performance (uplinks up to 10 Gigabit/s) and security and<br />
integrity of data, because eavesdropping is almost impossible.<br />
For logical security based on the functionality of the internet<br />
protocol suite TCP/IP a packet filter firewall combined with<br />
stateful inspection at the access point to the internet (a Cisco<br />
6509 router with hardware-based firewall module) is implemented,<br />
where all the incoming/outgoing packets are<br />
checked against a set of blocking or granting rules.
Additionally all incoming electronic mail is scanned for<br />
viruses and only clean and unobjectionable data (based on<br />
known problems) will be passed to the internal network, the<br />
rest gets quarantined. Spam mail marking is also active.<br />
Based on a level of probability users can define and set filter<br />
threshold values at their PC’s email client. In addition the<br />
individual activation of “greylisting” drastically reduces the<br />
incoming of unwanted emails.<br />
After having successfully renovated the old building of the<br />
computer center, a very flexible passive network structure<br />
with fixed and hidden loose cables has been installed. The<br />
active part of the data network is made up of a state-of-theart<br />
high-performance switch-router Foundry MLX, where<br />
all the supercomputer and server nodes get attached with the<br />
highest performance available. The coupling of the new<br />
BlueGene/P system with the storage subsystems was accomplished<br />
with a 10-Gigabit-only Force10-E600 switch-router.<br />
Data Acquisition and Data Bases for Plasma Fusion<br />
Experiments<br />
The main task of the XDV group at the computer center in<br />
Garching is to develop the data acquisition and data storage<br />
system for the W7-X experiment in Greifswald. This work<br />
is done in close cooperation with the experiment control<br />
group, the data analysis group as well as the diagnostic and<br />
physics department.<br />
The scheduling of the long discharges of W7X will be done by<br />
predefining operational parameters in segments and scenarios.<br />
Segments are valid for a certain amount of time and a scenario<br />
is a fixed sequence of segments with a special physical background.<br />
These segments contain very detailed but necessary<br />
information for the hardware and software to operate the discharge.<br />
Apart from the technical view of the segments the<br />
experiment leader or physicist needs a more physical view to<br />
the discharge description. Therefore an abstraction layer was<br />
introduced that only shows physically interesting information<br />
(high-level parameters). An executable segment will be generated<br />
after verifying the consistency of these high-level parameters<br />
by using a transformation function for every technical<br />
parameter involved. The definition of the necessary structures<br />
and interfaces is finished and by the end of <strong>2007</strong> some sample<br />
implementations of transformation functions have been<br />
available. The implementation of object life cycles, object<br />
states and user access rights on objects is completed. The<br />
package is used by the editors to visualize object properties<br />
and to handle access to objects in a safe and consistent way.<br />
By the end of <strong>2007</strong> the generic editor (Confix) for the structures<br />
in the data base has reached its intended functionality.<br />
The Confix editor works on all kind of objects in the data base<br />
and can only safely be used by an experienced user who knows<br />
about the structure and the object relations. The physicists<br />
need much simpler and more specialized editors for defining<br />
Computer Center Garching<br />
98<br />
configurations, segments and scenarios. The introduction of<br />
the physics abstraction layer with the high-level parameters<br />
is the basis for these editors and reduces the information presented<br />
to the user considerably. At the moment two editors are<br />
in development and first versions with basic functionality<br />
are already available. The group configuration editor is used<br />
to edit and define the description of components containing<br />
several control stations (fast control stations and data acquisition<br />
stations). It handles stations, the communication description<br />
necessary to operate the stations as well as the<br />
definition of the high-level parameters and the corresponding<br />
transformation functions. The segment editor has all the features<br />
to handle segment descriptions for components and<br />
projects. If not specified differently all high-level parameters<br />
are displayed in a standard way. If anything is changed, the<br />
segments may be saved and by using the specified transformation<br />
function, translated to the technical description used<br />
for machine operation. Both editors use the life cycle package<br />
to handle access rights and segment states correctly.<br />
The implementation of the complete control and data acquisition<br />
system of W7X on the already existing and simpler<br />
WEGA device reaches its first milestone at the beginning of<br />
2008. The control and data acquisition will then be replaced<br />
by the new system. At the moment the first test runs are<br />
accomplished and show promising results. Continuing tests<br />
will also incorporate physicists of W7-X to show the efficiency<br />
of the user interfaces and structures.<br />
Initiated by the ASDEX-Upgrade CODAC (Control and Data<br />
Acquisition) team, a new standard data acquisition station<br />
was defined and constructed. Based on the serial optical link<br />
(Hotlink standard) and a proprietary backplane defined locally,<br />
several remotely available ADCs of various sample speeds<br />
can be connected to any standard computers equipped with<br />
PCI or Compact PCI slots. This solution allows the build-up<br />
of data acquisition systems with a large number of channels.<br />
Staff<br />
A. Altbauer, G. Bacmeister, V. Bludov, G. Bronold, R. Bruckschen,<br />
J. Daschner, K. Desinger, R. Dohmen, R. Eisert * , I. Fischer,<br />
S. Groß * , K. Gross, C. Guggenberger, A. Hackl, C. Hanitsch,<br />
C. Hanke, R. Hatzky, S. Heinzel, F. Hinterland, M. Kölbl,<br />
G. Kühner * , H. Lederer, K. Lehnberger, J. Mejia, K. Näckel * ,<br />
W. Nagel, M. Panea-Doblado, F. Paulus, A. Porter-Sborowski,<br />
M. Rampp, J. Reetz, H. Reuter, K. Ritter, S. Sagawe * ,<br />
R. Schmid, A. Schmidt, H. Schürmann * , J. Schuster,<br />
U. Schwenn, T. Soddemann, R. Tišma, S. Valet * , I. Weidl.<br />
Data Acquisition Group: T. Bluhm * , P. Heimann, C. Hennig * ,<br />
G. Kühner * , J. Maier, Ch. Meyer, H. Riemann * , M. Zilker.<br />
* <strong>IPP</strong> Greifswald
SERF<br />
Euro-Asian electricity model<br />
Coal and oil, in limited form<br />
also gas, are traded over long<br />
distances. On the global market<br />
single prices exist for coal and<br />
oil. In case of the secondary energy<br />
carrier electricity, the situation<br />
is different. Various independent<br />
or only loosely coupled<br />
markets exist.<br />
A simple linear model of the European and Russian power system<br />
was introduced. The model was optimised for minimal<br />
overall costs for installation, production and transport while<br />
varying the transportation capacities. The computed scenarios<br />
of the Eurasian network show that transport between neighbouring<br />
areas leads to more flexibility in power generation.<br />
Mainly this effect can be employed for better usage of base<br />
load processes and therefore lower energy costs and/or carbon<br />
dioxide emissions. Some of the disadvantages of renewable<br />
energies like wind power can be reduced. Advantages of a<br />
stronger link over a wide area between east end west are very<br />
dependent on conditions of standards and prices in the regions.<br />
Traffic in the global model<br />
One of the projects treated by the <strong>IPP</strong> energy and system studies<br />
group is the participation on the design of a global multiregional<br />
energy model. The goal of this model is to explore the<br />
conditions under which fusion energy can efficiently enter into<br />
the global energy market. This is realized by means of the<br />
TIMES model generator which relies on an economic optimization<br />
procedure. Presently the ETM is being revised by various<br />
European research groups within the framework of SERF activities.<br />
Our group takes care of the ETM transportation sector.<br />
Recent improvements of both the software and input data used<br />
reinforce the prospects for first sensible results. Responsible<br />
for roughly one fourth of the global energy demand, future<br />
Figure 1: Global energy consumption by private cars in two scenarios<br />
Energy and System Studies<br />
Head: Dr. Thomas Hamacher<br />
Energy issues start to dominate global and local<br />
politics. Climate changes and steadily rising oil<br />
prices are subjects of political summits and<br />
international meetings. System analysis is more<br />
than ever asked to prepare sound answers and<br />
present realistic outlooks to future developments.<br />
The group for energy and system studies<br />
is working on local and global, long and short<br />
term issues. This mix seems best to produce<br />
realistic long term visions.<br />
99<br />
transportation activities will have<br />
substantial impact on the entire<br />
energy system. As a first project,<br />
the ETM transportation technology<br />
base has been revised arriving,<br />
at a more generic treatment<br />
of future transportation demands.<br />
Various scenario studies have<br />
shown that the invention of very<br />
efficient private cars, driven by<br />
conventional fossil fuels, could<br />
lead to substantial fuel savings<br />
such that almost a stabilization of energy consumption by road<br />
traffic, notwithstanding the heavily growing demands, could<br />
be obtained, see Figure 1. In the near future a new treatment of<br />
transportation habits together with an extension and improvement<br />
of the ETM technology base will allow for a modal<br />
split of transportation activities and, therefore, provide a more<br />
realistic projection of future transportation energy needs.<br />
Urban Energy Systems<br />
Introduction<br />
The United Nation Population Fund asks for a “revolution in<br />
thinking” in the field of urban planning. Many cities in Asia,<br />
Africa and Latin America are expected to double their population<br />
over the next 30 years. Energy issues are certainly not the<br />
only problems of these cities but certainly some of the most<br />
pressing. Developing tools and methodologies to improve<br />
urban energy systems is vital for a global prosperous future.<br />
Still, the work of the <strong>IPP</strong> focuses on Europe for the beginning.<br />
Greifswald<br />
An urban energy system model for Greifswald was finalized.<br />
This linear optimization model was developed with the model<br />
generator TIMES. The model was used to analyse different scenarios<br />
of future energy supply and demand within the city of<br />
Greifswald. There are two different types of scenarios. One type<br />
deals with the different possibilities to reach self-determined<br />
objectives (e.g. a CO 2 -Cap), the other one analyses the reactions<br />
of Greifswald’s energy system under changing economic parameters<br />
(e.g. increasing energy source prices). Presently, a multiagent-model<br />
of Greifswald and its economic circuit is being developed<br />
with the software SeSAM. This model will be used to<br />
examine the effects of different energy paths to the local economy,<br />
which are defined with the former mentioned energy<br />
model. The <strong>IPP</strong> further tries to initiate an active climate protection<br />
process in Greifswald. The city council has passed a<br />
ten point climate protection program. In several teams the<br />
administration now deals with topics like energy efficiency,<br />
biogas using, better conditions for cycling, energetic reconstruction<br />
etc. In spring 2008 the first climate protection conference<br />
of Greifswald will take place in cooperation with the <strong>IPP</strong>.
Figure 2: Basis: a business as usual scenario, CO2-Bound: step by step<br />
reduction of CO emission of 40 %, Solar-City: usage of photovoltaic and<br />
2<br />
solar collector systems.<br />
Malacky<br />
Malacky is a small town in Slovakia close to Bratislava,<br />
which undergoes a tremendous economic growth. The <strong>IPP</strong><br />
develops an energy model especially for Malacky. The main<br />
emphasise of the model will be to describe a population<br />
which expects to increase the per capita income in the next<br />
two decades considerably and a landscape in which major<br />
industries are developed on the green field.<br />
Ungerhausen<br />
A possibility to solve the dilemma between the limited fossil<br />
resources and a growing global energy demand is to build<br />
up local supply concepts. Such regional concepts are mainly<br />
based on the conversion of solar energy, which is theoretically<br />
available in huge amounts. The main focus of this study<br />
is to compare two different conversion concepts of using<br />
solar energy to satisfy the electricity and heating demand of<br />
a model region in consideration of the efficiencies and economical<br />
boundaries.<br />
One concept is to use agricultural land and goods as well as<br />
local wood potentials to produce energy in combined heat<br />
and power processes. Here the analysis of flows of agricultural<br />
products is important, because the energy production<br />
competes with the production of food, e.g. milk or meat. If<br />
the agricultural structure allows for the planting of energy<br />
crops, energy potentials have to be estimated in a realistic<br />
manner and crop rotations have to be followed.<br />
The electricity production by photovoltaics is therefore a more<br />
physical way of converting the solar radiation. The concept<br />
of producing solar hydrogen is a possibility to generate heat<br />
from electricity as well. Comparing both conversion concepts<br />
shows a lot about potentials, consequences and limitations of<br />
the substitution of fossil energy sources. Using combined heat<br />
and power processes is the most effective way to reduce CO 2<br />
emissions. The most efficient way of using the solar energy<br />
is the installation of photovoltaic modules, because biomass<br />
actually converts the solar radiation with efficiency of 1 %.<br />
Energy and System Studies<br />
100<br />
ESCOBALT<br />
The ESCOBALT project was finished in 2008. Results and<br />
findings of the project can be found on the internet. One of<br />
the goals, to create an energy saving network in the Baltic<br />
Sea, was certainly reached. The Baltic Sea region is unique<br />
in its variety for different concepts to supply energy.<br />
Methodologies<br />
Stochastic programming<br />
The German electricity system is expected to undergo major<br />
transitions in the future. Drivers of the expected change are<br />
the political decision to phase out nuclear energy and the<br />
confession to fulfil the Kyoto protocol. But also uncertain<br />
factors like weather conditions or price developments have<br />
an influence on the decision; therefore it is important to perform<br />
risk analyses. With the help of stochastic programming<br />
techniques, such uncertainties can be trapped to a certain<br />
point. A stochastic linear program of the German electricity<br />
system was developed to generate a system causing the<br />
minimal total costs in consideration of uncertainties. The<br />
fuel prices, the CO 2 prices and the wind supply where regarded<br />
as stochastic elements. Within this work the influence<br />
of wind to the existing system was analysed and the<br />
phase out of nuclear energy as well as CO 2 reduction scenarios<br />
were studied.<br />
EPS<br />
The <strong>IPP</strong> helps the European Physical Society to establish a<br />
working group on energy issues. The goal of this working<br />
group is to develop proposals for a sound European energy<br />
research in the field of physics. While the EPS is here certainly<br />
in competition with various other actors, the EPS<br />
offers the chance to develop balanced and independent<br />
views.<br />
Outlook<br />
Energy system studies will certainly become even more<br />
important in the future. The problem remains that talking<br />
about the future requires a very special care and adequate<br />
methodologies. Only work which is well aware of these<br />
methodological deficiencies will be able to make sound and<br />
helpful future outlooks.<br />
Scientific Staff<br />
Group: M. Bartelt (Uni Greifswald), M. Baumann (TU Graz),<br />
F. Botzenhart (Uni Augsburg), S. Braun (Uni Greifswald),<br />
G. Dressler (FH Stralsund), J. Düweke, T. Hamacher,<br />
N. Heitmann, J. Herrmann, M. Krüger (FH Wismar), P. Kurz<br />
(Uni Greifswald), P. Mühlich.
Charged Water Clusters<br />
Many aspects of the photoelectron<br />
spectra of free molecules<br />
are well understood. On the other<br />
hand, electron spectroscopy of<br />
liquids has only become possible<br />
recently and is a field of rapidly<br />
growing interest. Photoelectron<br />
spectra of liquid water differ in a<br />
number of respects from the mole-<br />
cule: Features due to ionic state vibrations, a characteristic<br />
of molecular conformational changes, are smeared out or<br />
absent in the liquid. Ionization energies of all orbitals shift towards<br />
lower values. The value of the vertical ionization energy<br />
of the least strongly bound electrons in the liquid has been<br />
measured some years ago. In our study of free water clusters,<br />
we show how this literature value is smoothly approached<br />
when ionization of clusters of increasing size is studied.<br />
HOMO Energy Shift to Monomer (eV)<br />
1.6<br />
1.4<br />
1.2<br />
1.0<br />
0.8<br />
0.6<br />
0.4<br />
0.2<br />
0.0<br />
0.0<br />
0.2<br />
0.4 0.6<br />
N-1/3 Figure 1 gives a graphical representation of the shift in photoionization<br />
energy of water clusters. Experimentally, clusters<br />
are produced by supersonic expansion of water vapour<br />
into vacuum. Clusters with a rather broad size distribution<br />
are thus produced, the mean of which can be varied by<br />
changing the expansion conditions (pressure and nozzle<br />
temperature). An empirical scaling law, derived from mass<br />
spectrometry of cluster beams, was used for estimating this<br />
mean size. The energy plotted in figure 1 is measured from<br />
the adiabatic peak in the isolated molecule to the maximum<br />
of the first photoelectron peak in the cluster.<br />
The linear dependence of these energies vs. inverse size is in<br />
line with expectation, if their main origin is the polarization<br />
Electron Spectroscopy<br />
Head: PD Dr. Uwe Hergenhahn<br />
Photoelectron spectroscopy is a valuable tool<br />
for the study of material properties, as seen for<br />
example by its use in the investigation of fusion<br />
reactor wall materials. In fundamental studies<br />
of its application to materials in general we<br />
have measured photoelectron and autoionization<br />
spectra from free water clusters. The sizedependent<br />
vertical ionization energies are shown<br />
for the first time.<br />
Cluster<br />
Monomer<br />
Liquid Water<br />
0.8<br />
1.0<br />
Figure 1: Energy difference of the least strongly bound photoelectrons of<br />
water clusters as a function of inverse cluster size. N is the mean value of<br />
the number of molecules in the cluster. The asymptotic value for liquid<br />
water is taken from the literature.<br />
101<br />
Autoionization of Clusters<br />
screening of the positive hole in<br />
the cluster. Initial state effects,<br />
surface charging and changes<br />
of the nuclear framework in the<br />
ionization process are thus found<br />
to be of minor importance. For<br />
the latter, this is confirmed by<br />
the fact that these shifts are<br />
practically identical in heavy<br />
water (D 2 O).<br />
The influence of the chemical environment on autoionization<br />
in weakly bonded systems has been studied recently,<br />
and a new transition pathway, which is only possible<br />
because of the cluster environment, identified (Intermolecular<br />
Coulombic Decay, ICD). ICD is expected to be a<br />
universal phenomenon, but so far has only been identified in<br />
noble gas clusters. The presence of a large quantity of low<br />
kinetic energy electrons coincident with primary inner<br />
valence photoelectrons from water clusters is the first experimental<br />
evidence for ICD in a hydrogen bridge-bonded system<br />
(figure 2). The same set-up was used to record electronelectron<br />
coincidence spectra of Ne clusters. Here, ICD is<br />
well-known from our experiments using a conventional<br />
(non-coincident) spectrometer. These earlier findings were<br />
beautifully corroborated.<br />
Coinc. Events /eV<br />
Kinetic Energy (e1) (eV)<br />
10000<br />
8000<br />
6000<br />
4000<br />
2000<br />
0<br />
16<br />
14<br />
12<br />
10<br />
8<br />
6<br />
4<br />
ICD Spectrum<br />
Scientific Staff<br />
5 10 15 20<br />
Kinetic Energy (e2) (eV)<br />
250<br />
S. Barth (1-3/07), V. Ulrich (1-7/07), M. Mucke (8-12/07),<br />
M. Förstel (9-12/07), T. Lischke, A. M. Bradshaw, U. Hergenhahn.<br />
Inner Valence<br />
2<br />
Coinc. Events / (eV x eV)<br />
Photoelectron Spectrum<br />
0 2000 4000 6000<br />
Coinc. Events /eV<br />
Figure 2: Intensity map of photoelectron-secondary electron pairs for inner<br />
valence ionization of water clusters. The ionization energy was set to 45 eV.<br />
The joint emission probability for each combination of kinetic energies of the<br />
two electrons detected in coincidence is presented in the two-dimensional<br />
map. Spectra shown in the top and righthand panel pertain to summation over<br />
all secondary electron energies or all photoelectron energies, respectively.
University Contributions to<br />
<strong>IPP</strong> Programme
In <strong>2007</strong> there were some retirements<br />
of members of the Board<br />
of Scientific Directors at <strong>IPP</strong>.<br />
Prof. Behringer left <strong>IPP</strong> in August.<br />
To elect his successor within a<br />
joint appointment of Augsburg<br />
University and <strong>IPP</strong>, a colloquium<br />
took place at Augsburg University<br />
on December 11 th . In consequence<br />
of the retirement of<br />
Prof. Fußmann, the cooperation<br />
with the “Humboldt-Universität<br />
zu Berlin” ended in September.<br />
A concept for a new cooperation with the Technical University<br />
Berlin is in progress and is expected to be signed in 2008.<br />
Since fusion-relevant physics and engineering are not the most<br />
prevalent subjects in Germany’s academic landscape, sparking<br />
student’s interest in high-energy plasma physics and other<br />
fusion-relevant fields is a duty and delight. Teaching at universities<br />
therefore has a sound tradition at <strong>IPP</strong>. In <strong>2007</strong> there<br />
were about 107 contact hours at universities or universities<br />
of applied sciences in Germany or neighbouring countries:<br />
Augsburg, Bayreuth, Bochum, Ghent, Greifswald, Helsinki,<br />
Munich, Padua, Stralsund, Tübingen, Ulm and Vienna.<br />
Lecturing at universities is supplemented by the <strong>IPP</strong>’s<br />
“Summer University in Plasma Physics”: one week of lectures<br />
Country Postgraduates Postdocs<br />
male female male female<br />
Australia 1<br />
Austria 1<br />
Canada 1<br />
Chile 1<br />
Czech Republic 1<br />
France 1<br />
Germany 30 9 10 1<br />
Greece 1<br />
India 2 1 1<br />
Italy 3 1 1<br />
New Zealand 1<br />
Poland 1 1<br />
Romania 1<br />
Russia 1 2<br />
Spain 1<br />
The Netherlands 1<br />
Ukraine 1 3<br />
United States of America 1<br />
Yugoslavia 1<br />
38 14 26 3<br />
52 29<br />
Table 1: Countries of origin and sex of the 52 postgraduates and 29 postdocs<br />
at <strong>IPP</strong> (31.12.<strong>2007</strong>)<br />
Cooperation with Universities<br />
Author: Dr. Axel Kampke<br />
Many important goals in plasma physics and<br />
materials science have to be met on the way to<br />
a fusion power plant. Since this process will<br />
last another generation, <strong>IPP</strong> attaches great importance<br />
to the training of young scientists. The<br />
close interaction with the universities in teaching<br />
and research is therefore an important part<br />
of the mission of <strong>IPP</strong>. It has also borne fruit in<br />
recent years. Moreover, the joint projects, which<br />
exist with several universities, form an integral<br />
part of the <strong>IPP</strong> research programme.<br />
105<br />
given by <strong>IPP</strong> staff and lecturers<br />
from partner institutes providing<br />
detailed tuition in nuclear<br />
fusion – in <strong>2007</strong> for the 22 nd<br />
time at Greifswald.<br />
The international character of<br />
fusion research is also reflected<br />
in the countries of origin of graduate<br />
students at <strong>IPP</strong>: one fourth<br />
of the postgraduates and more<br />
than 60 per cent of the postdocs<br />
are from abroad. Table 1 shows<br />
the distribution with respect to<br />
country and sex of the 52 postgraduates and 29 postdocs at<br />
the end of <strong>2007</strong>. Due to the restricted time for their work at<br />
<strong>IPP</strong> the total numbers of supervised postgraduates and postdocs<br />
within <strong>2007</strong> are higher by a factor of 1.3 than the above<br />
mentioned numbers.<br />
In addition, <strong>IPP</strong> uses specific instruments developed by the<br />
<strong>Max</strong> <strong>Planck</strong> Society, the Helmholtz Association and the<br />
Deutsche Forschungsgemeinschaft (DFG) for more intensive<br />
networking with universities on a constitutional basis:<br />
• participation in the DFG Collaborative Research Centre<br />
Transregio 24, “Fundamentals of Complex Plasmas”, at<br />
Greifswald University<br />
• the “International <strong>Max</strong> <strong>Planck</strong> Research School on Bounded<br />
Plasmas” at Greifswald in cooperation with Greifswald<br />
University<br />
• a “Helmholtz Virtual <strong>Institut</strong>e” together with the Universities<br />
of Stuttgart and Karlsruhe and Karlsruhe Research<br />
Centre<br />
• two “Helmholtz Young Investigators Groups” – “Computeraided<br />
Materials Sciences”, headed by Dr. Ralf Schneider,<br />
and “Theory and Ab Initio Simulation of Plasma Turbulence”,<br />
headed by Dr. Frank Jenko – in cooperation with<br />
the Universities of Greifswald and Münster, respectively,<br />
• the “<strong>Max</strong>-<strong>Planck</strong> Young Investigators Group” “Turbulence<br />
in Magnetised Plasmas”, headed by Dr. Wolf-Christian<br />
Müller, and<br />
• the “Young Investigators Group” “Zonal Flows”, headed by<br />
last years “European Young Investigator Award” winner<br />
Dr. Klaus Hallatschek.<br />
The young investigators groups got founded a common 500thousand-Euro-Linux-Cluster<br />
by the Helmholtz Association.<br />
In 2006 <strong>IPP</strong> was successful within the “Excellence<br />
Initiative” of the German government; the proposals for<br />
“Munich Centre for Advanced Photonics” and “Origin and<br />
Structure of the Universe” – both in cooperation with LMU<br />
and TUM – were accepted as “Clusters of Excellence”. In<br />
<strong>2007</strong> “Origin and Structure of the Universe” was officially<br />
established in the former “ITER building” of the <strong>IPP</strong>.
Species distribution [% n e ]<br />
University of Augsburg<br />
Lehrstuhl <strong>für</strong> Experimentelle <strong>Plasmaphysik</strong><br />
Head: Prof. Dr. Kurt Behringer<br />
Low Temperature Hydrogen<br />
at the NBI source. A pressure<br />
Plasmas<br />
variation at GLADIS showed<br />
that increasing the pressure at<br />
Basic investigations on diagnos-<br />
constant RF power causes a<br />
tics and modelling of low temperature,<br />
low pressure plasmas<br />
with hydrogen (or deuterium) ad-<br />
strong increase in H<br />
mixtures are carried out at inductively<br />
driven RF plasmas,<br />
microwave excited and electron cyclotron excited plasmas<br />
covering a wide range of pressure and input power and thus,<br />
a wide plasma parameter range. Focus is laid on molecular<br />
plasma physics. The methods developed are applied to the<br />
cold edge plasma of ASDEX Upgrade and to several ion<br />
sources at the <strong>IPP</strong>.<br />
+ The research at the University focuses on the<br />
development and application of diagnostic<br />
methods for low temperature plasmas, in particular<br />
for hydrogen ion sources, and on studies<br />
of plasma-surface interaction. The work is carried<br />
out in close collaboration with several<br />
divisions of the <strong>IPP</strong>.<br />
and H + at 3<br />
the expense of H + . From the<br />
2<br />
measurements of the molecular<br />
radiation a gas temperature of<br />
1000 K has been obtained; the<br />
vibrational temperature could be estimated to be 5000-<br />
8000 K for H and, as expected, lower for D : 3000-5000 K.<br />
2 2<br />
In order to measure the electron energy distribution function<br />
(EEDF) directly, the Boyd-Twiddy setup has been applied to<br />
a conventional Langmuir probe system. Since a voltage ramp<br />
is superposed by an AC modulated signal, the current at the<br />
modulation frequency directly yields the EEDF, whereas the<br />
80<br />
70<br />
60<br />
50<br />
40<br />
30<br />
nH /n H2<br />
20<br />
H<br />
10<br />
0<br />
0.25<br />
0.20<br />
0.15<br />
0.10<br />
0.05<br />
0.00<br />
DC current yields the plasma potential, the floating potential,<br />
and the electron and ion saturation currents. In addition, an<br />
RF disturbance is automatically filtered by a fast Fourier<br />
transformation. Measurements carried out at the experiments<br />
at the University show a good agreement between the conventional<br />
Langmuir probe and the Boyd-Twiddy technique,<br />
the latter being much less noisy. The setup has been transferred<br />
to the high power (P=60-120 kW), RF driven, negative<br />
hydrogen ion sources developed at <strong>IPP</strong>. EEDF’s are shown in<br />
the ITER section of this report. Electron density profiles on<br />
the central axis of the negative ion source BATMAN from the<br />
plasma grid to the driver are shown in figure 2 for two grid<br />
configurations (LAG and CEA). A low and a high bias current<br />
(1 A and 10 A) have been applied to reduce the amount of coextracted<br />
electrons. The electron density decreases exponentially<br />
over 4 cm towards the grid, being drastically depleted<br />
at 10 A for both grids. It was assumed that the position of the<br />
magnets for the magnetic filter field (FF) determines the<br />
sheath of electron depletion; however, the measurements<br />
clearly show a correlation with the grid position.<br />
+ H<br />
3<br />
+ H<br />
2<br />
+<br />
D<br />
nD /n D2<br />
+<br />
D + 2<br />
D + GLADIS<br />
AUG:NBI-RF source<br />
3<br />
0 15 20 25 30 60 70 80 90<br />
RF power [kW]<br />
Figure 1: Species distribution and the atomic to molecular density ratio in<br />
two positive ion RF sources at <strong>IPP</strong><br />
Two RF driven positive hydrogen ion sources, one of the neutral<br />
beam injection system (NBI) at ASDEX Upgrade and the<br />
one of the high heat flux test facility GLADIS were investigated<br />
by spectroscopic techniques at different RF input powers.<br />
The NBI source at ASDEX Upgrade works at higher<br />
powers, has a rectangular body, and worked with deuterium<br />
during the measurements, whereas the smaller cylindrical<br />
GLADIS source works with hydrogen at lower power levels.<br />
The ion species distribution was determined by H α -Doppler<br />
spectroscopy of the extracted ion beams. In addition, the radiation<br />
of atoms and molecules in the source plasma itself was<br />
measured to determine the density ratio of atoms to molecules.<br />
As shown in figure 1 the ion species distribution and the atomic<br />
to molecular density ratio depend clearly on input power.<br />
Furthermore, the assumption that a higher RF input power<br />
increases the degree of dissociation of the molecules and<br />
accordingly the atomic ion fraction has been confirmed and<br />
quantified. The difference in absolute values and ion species<br />
distribution among the two sources is most probably due to the<br />
different RF power and gas pressure which are both higher<br />
Density ratio: atoms/molecules<br />
107<br />
Electron density [m -3 ]<br />
5x10 17<br />
10 17<br />
CEA grid<br />
LAG grid<br />
magnets<br />
FF<br />
CEA<br />
LAG<br />
full symbols: 1A bias<br />
open symbols: 10A bias<br />
10<br />
-6 -4 -2 0 2 4 6 8 10 12 14 16 18 20<br />
Axial direction [cm]<br />
16<br />
Figure 2: Electron density profiles for two different grids (at low and high<br />
bias current) of the <strong>IPP</strong> negative ion source BATMAN
Since evaporation of cesium and the formation of Cs layers<br />
on metal surfaces play a key role in negative hydrogen ion<br />
sources, basic investigations on Cs behaviour in hydrogen<br />
plasmas have been started at the University in <strong>2007</strong>. To<br />
determine the thickness of a Cs layer, a specially designed<br />
quartz-crystal-microbalance is used that measures the frequency<br />
difference between two oscillating crystals. Figure 3<br />
(inlay) shows the measured correlation between Cs evaporation<br />
using a Cs dispenser at different currents and the<br />
change in frequency and thus the film thickness. In contrast<br />
to studies in high-purity conditions, the growth of Cs onto<br />
the examined surfaces (Cu, Mo, W, steel) is inhomogeneous;<br />
the cesium forms local, drop-like structures with a size of<br />
several μm. SEM pictures show that only 20-30 % of the<br />
metal is covered by those structures; consequently the measured<br />
thickness represents an effective thickness. In addition,<br />
a method for in-situ measurements of the work function<br />
using the photoelectrical effect (Fowler method) has been<br />
established. As shown in figure 3 the work function decreases<br />
with the Cs coverage of the molybdenum surface; however<br />
the work function does not fall below 2.8 eV towards the<br />
expected 2.2 eV for pure Cs.<br />
Work function [eV]<br />
4.4<br />
4.2<br />
4.0<br />
3.8<br />
3.6<br />
3.4<br />
3.2<br />
3.0<br />
2.8<br />
0.0<br />
Frequency change [Hz]<br />
600<br />
500<br />
400<br />
300<br />
200<br />
100<br />
Plasma Surface Interaction Studies<br />
0<br />
6.5A<br />
dispenser<br />
current<br />
7A 7.5A<br />
0 300 600 900 1200<br />
Dispenser on-time [s]<br />
0 10 20 30 40 50 60<br />
Effective cesium thickness [nm]<br />
Figure 3: Work function of a cesium layer on molybdenum as a function of<br />
the effective thickness. The inlay shows the thickness of the Cs layer during<br />
Cs evaporation using a dispenser.<br />
In strong collaboration with the materials research group at<br />
<strong>IPP</strong>, the ongoing work on chemical erosion of different<br />
doped carbon materials in low pressure ICP hydrogen and<br />
deuterium plasmas has now been focused on the one hand on<br />
the effect of the dopant distribution, i.e. carbide grain size<br />
and on the other hand on manufacturing and surface temperature<br />
effects on the erosion yield (released carbon particles<br />
per incident ion). Doping of carbon leads to a reduction of<br />
the effective carbon surface and thus to a reduced erosion<br />
University of Augsburg<br />
60<br />
50<br />
40<br />
30<br />
20<br />
10<br />
0<br />
Cesium thickness [nm]<br />
108<br />
yield in hydrogen plasmas. In-situ measurements of the fluence<br />
resolved erosion yield were carried out by optical<br />
emission spectroscopy (CH and C 2 band emission) in combination<br />
with weight loss measurements and RBS measurements.<br />
The incident ion flux towards the surface was measured<br />
using an energy resolved mass spectrometer in combination<br />
with a Langmuir probe. The effect of the dopant distribution<br />
was studied with amorphous carbon layers with atomically<br />
disperse distribution and different concentrations of the<br />
dopant materials (V, Ti, W). Another set of these samples<br />
was previously annealed at up to 1100 K leading to the formation<br />
of carbide grains with a size of several nm depending<br />
on dopant material and concentration. Figure 4 shows the<br />
results for vanadium doped samples with a surface temperature<br />
of 300 K and incident ion energy of 30 eV in deuterium<br />
plasmas. The solid line represents the erosion yield of undoped<br />
amorphous carbon. The yields show a strong decrease<br />
with the fluence and depend strongly on the dopant concentration.<br />
This strong reduction of the erosion yield can be<br />
explained by a surface enrichment of the dopant material<br />
which was proven by RBS measurements at the <strong>IPP</strong>. The<br />
pre-annealed samples always show significantly higher<br />
yields compared to samples without annealing; an effect<br />
which is less pronounced for titanium doped layers due to a<br />
less effective grain formation by annealing.<br />
Erosion yield G C /G ion [%]<br />
10<br />
1<br />
8.5%V<br />
Scientific Staff<br />
8.5%V<br />
pre-annealed<br />
1.5%V<br />
3.5%V<br />
Dopant: V<br />
3.5%V<br />
pre-annealed<br />
a-C<br />
1.5%V<br />
pre-annealed<br />
0.1<br />
0.0 0.5 1.0 1.5 2.0<br />
Fluence [1024 m-2 ]<br />
Figure 4: Erosion yields of vanadium doped amorphous carbon with atomically<br />
disperse dopant distribution and nm-sized carbide grains (preannealed)<br />
considering different concentrations of the dopant in ICP discharges<br />
with deuterium<br />
U. Fantz, P. Starke, S. Dietrich, S. Briefi, J. Ebad-Allah,<br />
D. Filimonov, S. König, A. Manhard, P. Schmidt.<br />
Energy scenarios group: J. Herrmann, F. Botzenhart, B. Grotz,<br />
A. Hämmerle, T. Hartmann.
Elementary reactions of<br />
hydrogen atoms with adsorbates<br />
and solid surfaces<br />
University of Bayreuth<br />
Lehrstuhl <strong>für</strong> Experimentalphysik III<br />
Head: Prof. Dr. Jürgen Küppers<br />
A considerable fraction of the species<br />
impinging on the first wall of<br />
a fusion experimental vessel are<br />
neutrals and ions in the energy<br />
range below a kinetic energy of about 10 eV. These particles are<br />
not capable of causing physical sputtering, but can induce several<br />
processes, such as chemical erosion, abstraction etc, which<br />
contaminate the plasma. Since low-energy ions are neutralised in<br />
the immediate vicinity of a substrate by resonance neutralisation,<br />
it is sufficient to study low-energy atom-surface interaction.<br />
For experimental reasons, the present work utilised only<br />
thermal atoms with energies in the range of a few tenth of an eV.<br />
Interaction of thermal hydrogen atoms with graphite basal<br />
plane surface leads to the formation of weak C-H bonds on<br />
top of C in a unique bonding scheme. The rigidness of the C<br />
lattice in which C-H groups are embedded prevents a full<br />
rehybridization towards strong tetrahedral sp 3 C-H bonds as<br />
are present in alkanes. Using ultra sensitive thermal desorption<br />
spectroscopy, we have found atomic and molecular<br />
hydrogen release upon thermal activation between about<br />
100 K and 700 K. First thermal (2000 K) hydrogen atoms<br />
a<br />
Mass spectrometer signal 10 -12 A)<br />
0.2<br />
0<br />
0.6<br />
0.4<br />
0.2<br />
0<br />
D 2<br />
D<br />
340 K<br />
340 K<br />
490 K<br />
580 K<br />
Cooperation between <strong>IPP</strong> and the University<br />
of Bayreuth is concentrated on investigating<br />
fusion-relevant plasma-wall interaction processes.<br />
Accordingly, the hydrogen atom surface<br />
chemistry on possible reactor wall materials is<br />
the primary research topic.<br />
b<br />
6<br />
4<br />
2<br />
0<br />
2<br />
D 2<br />
D<br />
109<br />
stick with a probability of about<br />
0.1 (figure 2b) and activate the<br />
surface towards adsorption of<br />
further atoms in close proximity.<br />
The total hydrogen sticking efficiency<br />
increases up to about<br />
0.4 and cluster of nearby C-H<br />
groups grow very efficiently.<br />
Figure 1 displays thermal desorption data of D coverages on<br />
graphite from 0.00008 to 0.5 ML. Measurements with H exhibit<br />
the same spectral features. The icons in the figure correspond to<br />
the adsorption geometries deduced by STM. The assignment is<br />
based on the simultaneous appearance of spectral features in<br />
TDS after selected D exposure and is in line with measurements<br />
of the adsorbed structures left behind on the surface after<br />
progressive heating. The various local maxima in TDS originate<br />
from dissociation of C-D groups in different types of adsorbed<br />
clusters. Figure 1a displays a sequence of atomic and recombinative<br />
molecular desorption spectra for D coverages below<br />
0.001 ML. At the smallest D coverages only desorption of<br />
atoms from isolated C-D groups with a maximum at 340 K is<br />
observed. After higher D exposures (figure 1b), predominantly<br />
pairs of C-D groups dissociate via release of D 2 , as can be<br />
deduced from the main D 2 desorption peaks located at 490 K<br />
(pairs with 3, 5 and 7 multiples of a cc ), and 580 K (para pairs).<br />
340 K<br />
490 K<br />
340 K<br />
450 K<br />
580 K<br />
0<br />
0<br />
200 400 600<br />
200 400 600<br />
200 400<br />
Temperature (K) Temperature (K) Temperature (K)<br />
600<br />
c<br />
120<br />
80<br />
40<br />
0<br />
4<br />
2<br />
D 2<br />
D<br />
265 K<br />
500 K<br />
540 K<br />
580 K<br />
450 K<br />
520 K<br />
Figure 1: Thermal desorption of D and D2 from the graphite basal plane after exposure to D at 150 K surface temperature (26). TD spectra were recorded with heating<br />
rates of 1 K/s and desorbing D atoms were detected via HD formed upon collision with the chamber walls. No other desorbing species could be detected. (a) TDS<br />
data from a surface dominated by isolated C-D groups (coverage 0.00008 to 0.001 ML, D exposures were: black 0.0008 ML, red 0.002 ML, green 0.0048 ML, blue<br />
0.01 ML). (b) TDS data from a surface dominated by pairs (coverage 0.001 to 0.02 ML, exposures were: black 0.01 ML, red 0.02 ML, green 0.04 ML, blue 0.08 ML).<br />
(c) TDS data from a surface dominated by big adsorbed clusters (coverage 0.02 to 0.5 ML, exposures were: black line 0.1 ML, red line 0.2 ML, green line 0.3 ML,<br />
blue line 0.5 ML, magenta line 1.0 ML, cyan line 2.0 ML, black symbols 3.0 ML, red symbols 10 ML, green symbols 40 ML, blue symbols 100 ML).
Since D 2 desorbs at higher temperatures than D, it is immediately<br />
clear that a C-D bond gets stronger if a neighbour C-D<br />
group is present in a distance of an odd multiple of a cc on the<br />
surface. Moreover, the spectra in figure 1b show that the<br />
molecular desorption peaks are preceded by an atomic peak<br />
at about 450 K. This shows that in a bigger cluster like a<br />
triple, less stable and stable C-D groups exist, of which the<br />
first dissociate via ejection of D atoms and the latter via<br />
ejection of D 2 molecules. The occurrence of single ortho<br />
pairs in STM coincides with the development of an additional<br />
desorption state which is at high coverage visible as a<br />
shoulder in TD spectra at about 540 K (figure 1c). These<br />
ortho pairs arrange in bigger entities which do not exhibit<br />
clearly distinguishable dissociation temperatures but lead to<br />
desorption between 400 K and 540 K.<br />
Also visible in TD spectra is desorption below the dissociation<br />
temperature of isolated C-D groups. A small fraction of<br />
atomic desorption near 200 K at low coverage (figures 1a,<br />
1b) is seen. Approaching saturation coverage of 0.5 ML, a<br />
pronounced molecular peak located at 265 K (figure 1c)<br />
emerges. This shows the existence of rather unstable C-D<br />
bonds. As stabilization of C-D pairs was only observed with<br />
C-D group separations of odd multiples of a cc , it is suggested<br />
that C-D groups which are separated by even multiples of<br />
a cc from other C-D groups exhibit reduced stability and dissociate<br />
below RT. At low coverages, only atomic desorption<br />
from these unstable groups was observed. This can be understood<br />
by taking into account that by ejection of a D from<br />
such an unstable group a more stable isolated C-D group is<br />
left behind (see the highest coverage atomic D desorption<br />
trace in figure 1b). The mean distance between C-D groups<br />
decreases with coverage. Accordingly, atomic desorption<br />
below room temperature might originate from desorption of<br />
pairs separated by large even multiples of a cc and molecular<br />
desorption at 265 K might predominantly originate from<br />
meta pairs, which exhibit the smallest possible separation, 2 a cc .<br />
a<br />
coverage (ML)<br />
10 -2<br />
10 -3<br />
10 -4<br />
10 -5<br />
singles<br />
b<br />
0.2<br />
0.1<br />
total (D)<br />
pairs<br />
0<br />
singles<br />
10 0 0.05 0.10<br />
-3 10-2 10-1 D exposure (ML) D exposure (ML)<br />
University of Bayreuth<br />
pairs<br />
Figure 2: (a) Number of singles and pairs with respect to D exposure displayed<br />
on logarithmic scale. The values were deduced from integration of the respective<br />
TDS peaks shown in figure 1a, b. (b) D sticking efficiency with respect to D<br />
exposure. The values were deduced from the D coverage data shown in a.<br />
coverage/exposure<br />
110<br />
The thermal desorption data show that thermal hydrogen<br />
atoms adsorb very efficiently on the graphite basal plane<br />
and that C-H bonding energies can be much lower than previously<br />
thought.<br />
Publications<br />
S. Wehner, P. Hoffmann, D. Schmeisser, H. R. Brand, and<br />
J. Küppers: Influence of the substrate on the pattern formation<br />
of a surface reaction. AIP Conference Proceedings 913,<br />
121-126 (<strong>2007</strong>).<br />
Conference contributions<br />
T. Zecho, C. B. Fischer, G. Ehrenhaft, and J. Küppers:<br />
Chemical erosion of graphite (0001) surfaces with thermal<br />
H and D. IVC-17/ICSS-13 and ICN+T <strong>2007</strong>, Stockholm,<br />
Sweden, July <strong>2007</strong>.<br />
S. Wehner, S. Karpitschka, H. R. Brand, and J. Küppers:<br />
Musterbildung auf nicht rekonstruierenden Metalloberflächen:<br />
CO Oxidation auf Ir(111) und Pd(111). CRG-Workshop,<br />
Culmitz, July <strong>2007</strong>.<br />
S. Wehner, P. Hoffmann, D. Schmeisser, H. R. Brand, and<br />
J. Küppers: Pattern formation during the CO oxidation<br />
reaction on non reconstructing platinum group metal surfaces.<br />
X. Latin American Workshop on Nonlinear Phenomena<br />
(LAWNP <strong>2007</strong>), Arica (Chile), October <strong>2007</strong>.<br />
T. Zecho, A. Andree, C. B. Fischer, M. Le Lay, and J. Küppers:<br />
Hydrogenation of graphite and carbon nanotube surfaces<br />
with hydrogen atom beams. 2nd International Workshop on<br />
Materials Science and Nano-Engineering, Awaji Island,<br />
Osaka, Japan, December <strong>2007</strong>.<br />
Seminars<br />
S. Wehner, P. Hoffmann, D. Schmeisser, H. R. Brand, and<br />
J. Küppers: Pattern formation during the CO oxidation reaction<br />
on non reconstructing platinum group metal surfaces.<br />
FCFM-Seminar, Universidad de Chile, Departamento de<br />
Fisica, Santiago (Chile), October <strong>2007</strong>.<br />
S. Wehner, H. R. Brand, and J. Küppers: From adsorbed molecules<br />
to mesoscopic patterns: Experimental studies of the influence<br />
of noise on the CO oxidation reaction on Iridium(111)<br />
surfaces. Nonlinear dynamics: From small scales to coherent<br />
structures (396. Wilhelm and Else Heraeus-Seminar),<br />
Bayreuth, October <strong>2007</strong>.<br />
Scientific Staff<br />
T. Zecho
Plasmagenerator PSI-2<br />
Performing plasma diagnostic<br />
measurements with Langmuir<br />
probes one has to take into consideration<br />
possible disturbances<br />
of the plasma by the probe itself.<br />
Apart from the probe tip, there<br />
is especially the probe shaft that<br />
could influence the results of a<br />
measurement. To resolve this question, measurements were<br />
made of the electron temperature and density using two<br />
Langmuir probes. The probes were arranged in two positions:<br />
In the first case, they were aligned in azimuthal direction<br />
of the PSI-2 plasma column. In the second case, they<br />
were placed in the same axial plane but tilted to each other<br />
in azimuthal direction. Data was acquired keeping one<br />
probe at fixed position while the second one was scanning<br />
the plasma radially. We have found that, irrespective of the<br />
geometry, the electron temperature is not affected by the<br />
probe, however the electron density is. This result can be<br />
explained within a theoretical transport model in which the<br />
probe shaft acts as an additional particle sink (figure 1). It is<br />
interesting to note that the disturbance of the plasma by the<br />
probe takes place on a global scale.<br />
n e and T e [normalized]<br />
1.1<br />
1<br />
0.9<br />
0.8<br />
0.7<br />
T<br />
e<br />
n<br />
e<br />
Model<br />
The flow behaviour of plasmas in contact with a target surface<br />
was investigated. The ion velocity distribution function (ivdf)<br />
of Ar + ions was measured at different displacements from<br />
the target using LIF techniques (see <strong>Annual</strong> <strong>Report</strong> 2006).<br />
In addition to the ivdf, the electron temperature was measured<br />
by means of a Langmuir probe. Assuming T e =T i and combining<br />
the results from the ivdf and Langmuir probe measurements<br />
the Mach number M=u/c s was evaluated (u streaming<br />
velocity, c s =[(T e +T i )/m i ] 1/2 speed of sound). Figure 2 shows M<br />
and the electron density at different axial positions z (spatial resolution<br />
Δz~0.5 mm). Close to the target (z=0) the Mach number<br />
approaches unity in agreement with the prediction by Bohm.<br />
Humboldt-University of Berlin<br />
Arbeitsgruppe <strong>Plasmaphysik</strong><br />
Head: Prof. Dr. Gerd Fußmann<br />
-40 -20 0 20 40<br />
Radial Position x [mm] of Disturbing Probe<br />
Figure 1: Normalized electron density (red) and temperature (blue) measured<br />
at fixed position while a second probe was radially driven. The calculated<br />
density distribution is plotted in black.<br />
The plasma physics group at the Humboldt<br />
University operates the plasma generator PSI-2<br />
and the electron beam ion trap (EBIT). Research<br />
activities comprise basic plasma physics, plasmamaterial<br />
interactions and highly charged ion<br />
processes relevant to fusion experiments. Further<br />
effort is dedicated to the study of plasmoids produced<br />
on water surfaces at atmospheric pressure.<br />
111<br />
Our measurement is thus the<br />
first confirmation of Bohm’s<br />
criterion for conditions relevant<br />
to fusion experiments. An unexpected<br />
result is the short distance<br />
(Δz~5 mm) over which the<br />
final acceleration of the ions to<br />
M=1 takes place. Using a theoretical<br />
presheath model the measured<br />
profiles can be reproduced<br />
by relying on D=20 m 2 s -1 for the perpendicular diffusion coefficient.<br />
However, this D value is unrealistically large to explain<br />
the profiles solely by diffusion. A more refined analysis of our<br />
results suggests that radial electric fields build up in front of the<br />
target causing strong particle transport onto the target surface.<br />
M LIF<br />
M<br />
n LIF<br />
n<br />
-50 -40 -30 -20 -10 0 0<br />
z [mm]<br />
Figure 2: Mach number and electron density as a function of axial position<br />
Electron Beam Ion Trap (EBIT)<br />
To complement earlier work on the line emission from highly<br />
charged tungsten ions (see <strong>Annual</strong> <strong>Report</strong>s 1999 and 2000),<br />
x-ray spectra from Si-like W 60+ to Ne-like W 64+ were measured<br />
in the 1-2 Å wavelength region. Our study includes the directly<br />
excited L-shell spectra as well as the associated satellite<br />
emission originating from dielectronically excited W ions.<br />
Precise knowledge of such data is essential owing to the increasing<br />
use of tungsten as wall material in nuclear fusion<br />
devices. The tungsten ions in the EBIT were produced by<br />
directing a continuous flow of W(CO) 6 gas towards the trap<br />
and ionizing the injected carbonyl compound by the monoenergetic<br />
electron beam. Spectra were obtained for a number<br />
of beam energies between 10 and 20 keV and analyzed<br />
using high resolution x-ray spectroscopy. As an example, in figure<br />
3(a) we present a 15 keV electron beam energy spectrum<br />
showing lines from W 60+ to W 64+ recorded between 1.18 and<br />
1.57 Å. To support our identification of the lines, wavelengths<br />
and intensities were calculated for the ions under investigation<br />
using an atomic structure computer package combined<br />
with a collisional-radiative model (in cooperation with<br />
the division Tokamak Edge and Divertor Physics in Garching).<br />
n 0<br />
M 0<br />
1<br />
0.8<br />
0.6<br />
0.4<br />
0.2<br />
M or n/n 0
Intensity [cph]<br />
I [10-16 3<br />
Ph/s cm /Å]<br />
cs [10 -20 cm 2 ]<br />
100<br />
50<br />
0<br />
5<br />
0<br />
a)<br />
3p - 2s<br />
10 W 64+<br />
5<br />
4<br />
3<br />
2<br />
1<br />
0<br />
b) W 63+<br />
W 62+<br />
W 64+<br />
The results (figure 3b) show that atomic structure calculations<br />
can reproduce the general pattern of the observed spectra.<br />
The predictions for the wavelengths agree with the experimental<br />
values to within about 2-3 %.<br />
In a further experiment, measurements were made of the LMn<br />
(n=3-6) dielectronic-recombination (DR) resonances using a<br />
scanning technique described earlier (see <strong>Annual</strong> <strong>Report</strong> 1997).<br />
The DR process proceeds by capture of a free electron to a target<br />
ion forming an autoionizing doubly excited state followed<br />
by a stabilizing photon emission. Figure 3c shows the DR<br />
spectrum for the LMM resonance of tungsten ions with charge<br />
q
Introduction<br />
In ASDEX Upgrade thermographic<br />
measurements are used<br />
to monitor the surface temperature<br />
of in-vessel components<br />
during plasma discharges. The<br />
heat flux to the components is<br />
calculated from the measured<br />
temperature evolution. Carbon<br />
fibre composite (CFC), often used<br />
as target material, has a substructure in the ten micrometer<br />
range which causes a non-uniform temperature distribution<br />
even for a homogeneous heat load. This can be observed by<br />
measurements with a resolution in the dimension of the single<br />
fibers, as shown in figure 1. Some isolated spots reach much<br />
higher temperatures than the remainder, which are not in<br />
accordance with values expected from theory (figure 2) for a<br />
semi-infinite target. This behavior has influence on temperatures<br />
measured with a spatial resolution of a few millimeters<br />
and the calculated heat flux.<br />
Lock-In thermography<br />
Technical University of Munich<br />
Lehrstuhl <strong>für</strong> Messsystem- und Sensortechnik<br />
Head: Prof. Dr.-Ing. Alexander W. Koch<br />
The simplest thermographic method is to heat up with a short<br />
pulse of energy and to observe the decay of the temperature.<br />
Figure 1 shows a result of this method. A more sophisticated<br />
approach is Lock-In thermography. Instead of a short energy<br />
pulse the sample is heated continuously using a periodically<br />
modulated energy source. This results in the generation of a<br />
thermal wave in the sample. This thermal wave can be characterized<br />
by its amplitude and phase. Both, amplitude and phase,<br />
are affected by the whole domain in which the wave has formed.<br />
temperature / C<br />
160<br />
140<br />
120<br />
100<br />
80<br />
60<br />
40<br />
20<br />
pixel<br />
140<br />
120<br />
100<br />
80<br />
60<br />
40<br />
20<br />
0<br />
The cooperation of <strong>IPP</strong> and Technical University<br />
of Munich is concentrated on the development<br />
of thermography measurement techniques<br />
for surface characterisation. In general thermography<br />
is a means for temperature measurement<br />
of a surface by monitoring the emitted<br />
infrared radiation. With defined temperature<br />
stimulation it is used as a non-destructive and<br />
contact-less testing method.<br />
0 20 40 60 80 100 120 140<br />
pixel<br />
Figure 1: Spatial temperature distribution on a CFC sample heated with a<br />
32 ms Gaussian laser pulse (1 pixel = 30 μm)<br />
113<br />
A characteristic value is the thermal<br />
diffusion length μ, which is<br />
defined with f the frequency of<br />
the modulation and α the thermal<br />
diffusivity of the material as:<br />
For good heat conductors μ is high, i.e. about 6 mm for copper<br />
at a modulation frequency of 1 Hz, and low for bad heat<br />
conductors like steel with about 1 mm.<br />
(1)<br />
(2)<br />
Figure 2: Temperature devolution for one hot spot (1) and the homogeneous<br />
area (2) in the center of the laser pulse<br />
For the calculation of amplitude and phase four data points<br />
are required, which are acquired at time differences of T/4<br />
of the modulation period. With these four points the amplitude<br />
A for the whole monitored surface can be calculated<br />
according to<br />
and the phase ϕ according to<br />
⎛ I<br />
ϕ<br />
= arctan<br />
⎜<br />
⎝ I<br />
1<br />
2<br />
−<br />
−<br />
(3)<br />
Although both, amplitude and phase, are calculated from the<br />
same four data points the phase data has two advantages:<br />
• Amplitude data is sensitive down to a depth of about μ,<br />
phase data up to 2μ.<br />
I<br />
I<br />
3<br />
4<br />
⎞<br />
⎟<br />
⎟.<br />
⎠
• Phase data is insensitive for inhomogeneous heating, variations<br />
of the emission coefficient and similar negative<br />
effects influencing the original temperature data.<br />
The fact that the frequency dependent μ is a limit for the<br />
sensitivity range can be used for depth probing by varying<br />
the frequency systematically for both, amplitude and phase.<br />
Setup<br />
The surface temperature is measured using an infrared camera.<br />
The camera is provided with a microscope objective for<br />
a spatial resolution of about 30 μm. Frame rates above 1 kHz<br />
are possible while observing an area of about 4×4 mm². For<br />
the heating of the samples a fiber-coupled diode laser with<br />
an output power of 80 W is used. The wavelength of the<br />
laser radiation is in the near infrared at 980 nm. Because the<br />
cameras are sensitive between 3 μm and 5 μm, reflected<br />
heating power will not influence the measured signal. The<br />
current through the laser diode and with it the output power<br />
is controlled by an analog input voltage supplied by a frequency<br />
generator for the modulation part and an additional<br />
voltage source for the constant dc offset. Since the spot of<br />
the focused laser beam has a diameter of about 2.8 mm an<br />
average power density of above 10 MW/m² can be achieved.<br />
Amplitude / K<br />
60<br />
40<br />
20<br />
pixel<br />
250<br />
200<br />
150<br />
100<br />
50<br />
0<br />
Figure 3: Calculated amplitude for CFC sample<br />
100 150 200 250 300<br />
pixel<br />
Applying Lock-In thermography to a CFC sample shows at<br />
first the same inhomogeneous temperature distribution as for<br />
pulsed heating. Taking a look at the time devolution shows<br />
that for periodic heating both, the hot spots and the rest of the<br />
sample, follow the modulation signal with a higher amplitude<br />
for the hot spots. Calculating the amplitude and the phase<br />
shows hot spots also in the amplitude image (figure 3) as expected,<br />
but not in the phase image (figure 4), which is uniform.<br />
Technical University of Munich<br />
114<br />
phase / rad<br />
3<br />
2<br />
1<br />
0<br />
-1<br />
-2<br />
-3<br />
pixel<br />
250<br />
200<br />
150<br />
100<br />
50<br />
Amplitude and phase calculations with (2) and (3) have two<br />
drawbacks:<br />
• Depending on the relation of the recording rate and the frequency<br />
modulation it might not be possible to take data<br />
points with an exact difference of T/4 of the modulation<br />
period. This will result in an error which is not constant<br />
over the whole area.<br />
• Sometimes the recorded signal is not sinusoidal at all times<br />
as assumed in the derivation of (2) and (3), e.g. if the camera<br />
signal is saturated at temperatures. Even if half of the signal<br />
would be still evaluable it is not possible to get reasonable<br />
results with the given formulas.<br />
To overcome these problems new algorithms for phase and<br />
amplitude calculation have to been found which do not<br />
require a fixed value of T/4.<br />
Other activity<br />
Another field of activity is the support for high heat flux<br />
tests at the Materials Research division at the <strong>IPP</strong>. For the<br />
new stellerator Wendelstein 7-X divertor target elements<br />
will be tested in GLADIS, a testing facility with a high energy<br />
hydrogen ion beam used to apply numerous heat load pulses<br />
on each target element, to find defective ones before using them<br />
in real fusion experiments. Because there are many elements,<br />
a manual inspection of the recorded infrared data is not reasonable.<br />
With the adaption of ASDEX Upgrade software for<br />
thermographic data visualization and analysis, it will be<br />
possible to automate most of the data analysis.<br />
Scientific Staff<br />
M. Jakobi, P. de Marné.<br />
0<br />
Figure 4: Calculated phase for CFC sample<br />
100 150 200<br />
pixel<br />
250 300
ECRH in over-dense plasmas<br />
University of Stuttgart<br />
<strong>Institut</strong> <strong>für</strong> Plasmaforschung (IPF)<br />
Head: Prof. Dr. Ulrich Stroth<br />
The plasma in the torsatron TJ-K<br />
is generated by microwaves at<br />
2.45 GHz with a maximum power<br />
of 6 kW and at 8 GHz with a<br />
maximum power of 1.2 kW. The<br />
plasma density usually exceeds<br />
the cutoff density. With electron<br />
temperatures of T e ≤20 eV, absorption<br />
at the fundamental resonance<br />
is found to be inefficient<br />
for the O-wave as well as for the X-wave. This is true for<br />
both heating frequencies. Hollow T e profiles observed in the<br />
2.45-GHz-heated plasmas indicate power deposition at the<br />
plasma boundary, more precisely at the upper hybrid resonance<br />
(UHR). At the higher heating frequency the T e profiles<br />
become more flat indicating an increased power deposition<br />
at the plasma centre. This could be due to heating via<br />
electron Bernstein waves (EBW). The EBWs can be generated<br />
by the O-X-B mode-conversion process.<br />
Figure 1: Simulation of the O-X-B conversion performed with a FDTD fullwave<br />
code. Plotted is the positive value of the wave electric field.<br />
This conversion process was investigated in detail with the<br />
full-wave code IPF-FD3D. A simulation result is shown in<br />
figure 1. The O-mode is incident at an optimum angle with<br />
respect to the magnetic field lines from the lower left corner,<br />
indicated by the black arrow. The density gradient is parallel<br />
to the y-axis, the magnetic field parallel to the x-axis. At a<br />
region around the O-mode cutoff the O-X conversion<br />
occurs. The direction of propagation of the X-mode is indicated<br />
by the grey arrow. The X-B conversion happens at the<br />
UHR where the X-mode is converted into a backwards<br />
propagating EBW with the direction of propagation indicated<br />
by the light grey arrow. Furthermore does the formation<br />
of the EBW take some time: several hundred wave periods<br />
are necessary before the EBW reaches the O-mode cutoff.<br />
The joint program between IPF and <strong>IPP</strong> on<br />
ECRH systems for ASDEX Upgrade, W7-X,<br />
and ITER can be found on the respective pages<br />
of this annual report. Here is summarized the<br />
part of the program carried out at IPF, which is<br />
the development of new mm-wave components,<br />
investigations of plasma waves and turbulent<br />
transport. Experiments are carried out on the<br />
torsatron TJ-K, which is operated with a magnetically<br />
confined low-temperature plasma.<br />
115<br />
Array antenna for Bernsteinwave<br />
heating<br />
Bernstein waves are electrostatic<br />
waves, which are efficiently absorbed<br />
at the electron-cyclotron<br />
resonance. They can be used to<br />
heat over-dense plasmas, where<br />
they can be created in a so-called<br />
O-X-B mode conversion process.<br />
The conversion efficiency depends<br />
on the angle between the<br />
wave vector and the direction of the magnetic field at the O-cutoff.<br />
To investigate the O-X-B conversion process it is desirable<br />
to have an antenna with a steerable characteristic.<br />
The array antenna build for TJ-K has this capacity. In the<br />
frequency range from 7.9 to 8.4 GHz the emitted wave vector<br />
can be swept from -45° to +45°. Calculations of the O-X<br />
conversion have shown that the optimal angle of incidence<br />
of the microwave with respect to the magnetic field is about<br />
-45°. The measured characteristics fits rather well the theoretical<br />
one. The full width at half maximum of the pattern is<br />
at about 20°. The power levels of the next maxima are about<br />
20 dB below the main maximum. The main antenna loop<br />
can be steered to an angle of -42° which is close to the optimum<br />
value. Electron density measurements have shown that it is<br />
possible to produce over-dense plasma with the new antenna.<br />
The profile of the electron temperature of such over-dense<br />
plasma is flat over the entire minor plasma radius. This<br />
could be a sign of plasma heating due to Bernstein waves.<br />
Deposition measurements are in progress and first results<br />
show heating at the cyclotron resonance.<br />
Influence of the adiabaticity parameter on the spectral<br />
power transfer of density fluctuations<br />
The investigation of the dual turbulent cascade in drift-wave<br />
turbulence has been continued. Although being a one field<br />
model, the bispectral technique developed by Kim et al. was<br />
applied to 2D density and potential-fluctuation measurements,<br />
where one field (potential) was analysed for the energy<br />
(inverse) cascade and the other (density) for the enstrophy<br />
(direct) cascade. In <strong>2007</strong>, the validity of this approach has<br />
been tested on simulated data from a Hasegawa-Wakatani<br />
code. The key parameter for this study is the coupling coefficient<br />
C~1/ν, which inversely depends on the electron-ion<br />
collisionality ν. Simulation results were compared for a high<br />
value of C=2 with the value valid of the experiment of C=1<br />
and the result from the experimental data. In case of adiabatic<br />
electrons (C=2), density and potential fluctuations are<br />
strongly coupled and the spectral power of the density fluctuations<br />
follows that of the potential fluctuations, which is<br />
transferred as an inverse cascade to larger scales.
Most of the power transfer takes place at larger scales. For<br />
experimental conditions (C=1), the direction of power transfer<br />
of the density fluctuations has changed to the opposite<br />
direction and one can identify a local direct cascade at<br />
smaller scales, which is also expected for the enstrophy<br />
transfer. This cascade is also present in the potential fluctuations,<br />
but due to the weighting of the vorticity with k 2 it is<br />
much more pronounced in the enstrophy cascade. The simulation<br />
at the realistic value of C=1 agrees with the experimental<br />
result.<br />
Investigations of microwave material properties in a<br />
three-mirror resonator configuration<br />
For the construction of future fusion experiments like ITER<br />
and W7-X, where long-pulse, high-power ECR applications<br />
are planned, the definition of realistic cooling requirements<br />
of mm-wave components is crucial. To enlarge the data base<br />
on ohmic losses of reflectors due to finite conductivity,<br />
imperfections of the material, and especially surface modifications<br />
by long-term plasma exposition, various mirror samples<br />
have been investigated at 140 and 170 GHz using a<br />
three-mirror resonator. The losses depend on the position on<br />
the mirror, confirming strong influence of plasma on the invessel<br />
components. The absorption coefficients for 170 GHz,<br />
E-plane, 45° angle of incidence for a ASDEX Upgrade mirror<br />
are 0.36-0.44 % and for a W7-AS mirror 0.39-0.43 %.<br />
Additional measurements of the W7-AS mirror surface with<br />
a roughness detection instrument and spectroscopic analysis<br />
confirmed the strong influence of different surface deposits<br />
on mirrors, depending on the placement inside the torus.<br />
Measurements on non-exposed W7-X TZM mirrors yield<br />
comparable absorption with previous results for copper and<br />
aluminium surfaces, all significantly lower (0.21 %) than for<br />
the exposed samples.<br />
Optimization of smooth-wall HE 11 Horn antennas<br />
The existing waveguide codes were extended by a scattering<br />
matrix module, which allows the calculation of mode conversions<br />
due to diameter changes in cylindrical waveguides.<br />
In contrast to the faster coupled mode equation algorithm,<br />
the scattering matrix method does not neglect reflected<br />
waves and is not limited to slight diameter variations. Based<br />
on this, a program was developed, which optimizes the<br />
function r(z) (r: waveguide radius, z: axial coordinate) for<br />
given input- and output radii. Since mode conversion is<br />
highly dependent on the phase differences of coupled modes,<br />
the total length can also be changed by the optimizer. This<br />
code can be used to optimize any kind of mode converter<br />
with varying diameter. For a horn antenna, the wanted aperture<br />
field is expanded into a spectrum of complex mode<br />
amplitudes, which are then used as the optimization goal.<br />
University of Stuttgart<br />
116<br />
Figure 2 shows the measured far field of an optimized horn<br />
at 140 GHz in co- and cross polarization. The side-lobe level<br />
is very low the level of cross-polarization, however, is -17 dB,<br />
which is too high for some applications. The improvement<br />
of the codes for better results is an ongoing task.<br />
Figure 2: Far field of the horn antenna in co-polarization (left) and crosspolarization<br />
Materials with negative index of refraction<br />
The propagation of electromagnetic waves in waveguide<br />
structures with negative index of refraction has been investigated<br />
with a commercial full-wave solver (CST-Microwave<br />
Studio). Calculations and experiments on waveguides with<br />
different filling like thin wire structures, which exhibit behaviour<br />
similar to plasma (negative permittivity), and/or<br />
resonant structures like split rings (negative permeability)<br />
have been performed. Especially, experiments on TM 11 waveguides<br />
with wire structures confirmed the backward wave<br />
propagation at resonant frequency.<br />
For high-power applications in experimental plasma physics,<br />
feasibility studies on application of the principle of a negative<br />
refractive index, e.g. for backward-forward scanning<br />
leaky-wave antennas and other microwave components have<br />
been started. A design based on coaxial balanced CL-LC<br />
transmission lines is proposed. The optimization of the<br />
structures that allow high current-density handling, and<br />
numerical simulations using CST are underway. The excitation<br />
of backward waves based on coupled cavity chains was<br />
shown. The back-fire to end-fire scanning capability of this<br />
new metamaterial-based leaky-wave antenna for high power<br />
applications was numerically confirmed.<br />
Scientific Staff<br />
P. Brand, G. Birkenmeier, E. Holzhauer, H. Höhnle, A. Jooß,<br />
W. Kasparek, A. Köhn, H. Kumric, C. Lechte, N. Mahdizadeh,<br />
P. Manz, B. Nold, B. Plaum, K. Rahbarnia, M. Ramisch,<br />
L. Stollenwerk, U. Stroth.
Publications
Articles, Books and Inbooks<br />
Adelhelm, C., M. Balden and M. Sikora: EXAFS investigations<br />
of the thermally induced structuring of titanium doped amorphous<br />
carbon films. Materials Science and Engineering C 27,<br />
1423-1427 (<strong>2007</strong>).<br />
Albajar, F., N. Bertelli, M. Bornatici and F. Engelmann: Electron-cyclotron<br />
absorption in high-temperature plasmas: quasiexact<br />
analytical evaluation and comparative numerical analysis.<br />
Plasma Physics and Controlled Fusion 49, 15-29 (<strong>2007</strong>).<br />
Albajar, F., M. Bornatici and F. Engelmann: Electron cyclotron<br />
wave power loss in fusion plasmas: a model comparison.<br />
Nuclear Fusion 47, 1101-1105 (<strong>2007</strong>).<br />
Alimov, V. K. and J. Roth: Hydrogen isotope retention in<br />
plasma-facing materials: Review of recent experimental<br />
results. Physica Scripta T128, 6-13 (<strong>2007</strong>).<br />
Allen, F. I., C. Biedermann, R. Radtke and G. Fußmann: Charge<br />
exchange of highly charged argon ions as a function of projectile<br />
energy. Journal of Physics. Conference Series 58,<br />
188-191 (<strong>2007</strong>).<br />
Angioni, C., L. Carraro, T. Dannert, N. Dubuit, R. Dux, C. Fuchs,<br />
X. Garbet, L. Garzotti, C. Giroud, R. Guirlet, F. Jenko, O. Kardaun,<br />
L. Lauro-Taroni, P. Mantica, M. Maslov, V. Naulin, R. Neu,<br />
A. G. Peeters, G. Pereverzev, M. E. Puiatti, T. Pütterich, J. Stober,<br />
M. Valovic, M. Valisa, H. Weisen, A. Zabolotsky, ASDEX Upgrade<br />
Team and JET EFDA Contributors: Particle and Impurity<br />
Transport in Axial Symmetric Divertor Experiment Upgrade and<br />
the Joint European Torus, Experimental Observations and Theoretical<br />
Understanding. Physics of Plasmas 14, 055905 (<strong>2007</strong>).<br />
Angioni, C., R. Dux, E. Fable, A. G. Peeters and ASDEX<br />
Upgrade Team: Non-adiabatic passing electron response<br />
and outward impurity convection in gyrokinetic calculations<br />
of impurity transport in ASDEX Upgrade plasmas. Plasma<br />
Physics and Controlled Fusion 49, 2027-2043 (<strong>2007</strong>).<br />
Angioni, C., H. Weisen, O. J. W. F. Kardaun, M. Maslov,<br />
A. Zabolotsky, C. Fuchs, L. Garzotti, C. Giroud, B. Kurzan,<br />
P. Mantica, A. G. Peeters, J. Stober, ASDEX Upgrade Team<br />
and EFDA-JET Workprogramme: Scaling of density peaking<br />
in H-mode plasmas based on a combined database of AUG<br />
and JET observations. Nuclear Fusion 47, 1326-1335 (<strong>2007</strong>).<br />
Balden, M. and C. Adelhelm: Characterization and erosion of metalcontaining<br />
carbon films. Physica Scripta T128, 121-126 (<strong>2007</strong>).<br />
Balden, M., C. Adelhelm, E. De Juan Pardo and J. Roth:<br />
Chemical erosion by deuterium impact of carbon films<br />
Publications<br />
119<br />
doped with nanometer-sized carbide crystallites. Journal of<br />
Nuclear Materials 363-365, 1173-1178 (<strong>2007</strong>).<br />
Balden, M., C. Adelhelm, T. Köck, A. Herrmann and J. Jaimerena-<br />
Muga: Thermal nanostructuring of metal-containing carbon<br />
films and their nanoindentation testing. Invited Paper.<br />
Reviews on Advanced Materials Science 15, 95-104 (<strong>2007</strong>).<br />
Balden, M., C. Adelhelm and M. Sikora: Thermal stability<br />
and nano-structure of metal-doped carbon layers. Journal of<br />
Nuclear Materials 367-370, 1458-1462 (<strong>2007</strong>).<br />
Baldwin, M. J., R. P. Doerner, D. Nishijima, D. Buchenauer,<br />
W. M. Clift, R. A. Causey and K. Schmid: Be-W alloy formation<br />
in static and divertor-plasma simulator experiments.<br />
Journal of Nuclear Materials 363-365, 1179-1183 (<strong>2007</strong>).<br />
Barradas, N. P., K. Arstila, G. Battistig, M. Bianconi,<br />
N. Dytlewski, C. Jeynes, E. Kotai, G. Lulli, M. Mayer, E. Rauhala,<br />
E. Szilagyi and M. Thompson: International Atomic Energy<br />
Agency intercomparison of ion beam analysis software. Nuclear<br />
Instruments and Methods in Physics Research B: Beam<br />
Interactions with Materials and Atoms 262, 281-303 (<strong>2007</strong>).<br />
Becker, G. and O. Kardaun: Anomalous Particle Pinch and<br />
Scaling of ν in /D Based on Transport Analysis and Multiple<br />
Regression. Nuclear Fusion 47, 33-43 (<strong>2007</strong>).<br />
Behrisch, R. and W. Eckstein (Eds.): Sputtering by Particle<br />
Bombardment: Experiments and Computer Calculations from<br />
Threshold to MeV Energies. Topics in Applied Physics 110.<br />
Springer Verlag, Berlin (<strong>2007</strong>) 508 p.<br />
Behrisch, R. and W. Eckstein: Introduction and Overview.<br />
Sputtering by Particle Bombardment: Experiments and<br />
Computer Calculations from Threshold to MeV Energies.<br />
(Eds.) R. Behrisch, W. Eckstein. Topics in Applied Physics 110.<br />
Springer Verlag, Berlin, 1-20 (<strong>2007</strong>).<br />
Benito, A., D. Goitia, E. Casado, M. Anderez, E. Vázquez,<br />
M. Fajardo, C. Palacios, A. Cardella, D. Pilopp, L. Giordano<br />
and G. Di Bartolo: Manufacturing of the coil support structure<br />
for W7-X. Fusion Engineering and Design 82, 1579-1583<br />
(<strong>2007</strong>).<br />
Biedermann, C. and R. Radtke: Comment on “Direct observation<br />
of the 2 D 3/2 – 2 D 5/2 ground-state splitting in Xe 9+ ”.<br />
Physical Review A 75, 066501 (<strong>2007</strong>).<br />
Biedermann, C., R. Radtke, G. Fußmann and F. I. Allen:<br />
Extreme ultraviolet spectroscopy of highly charged argon<br />
ions at the Berlin EBIT. Journal of Physics. Conference<br />
Series 72, 012004 (<strong>2007</strong>).
Bierwage, A. and Q. Yu: Comparison between resistive and<br />
collisionless double tearing modes for nearby resonant surfaces.<br />
Plasma Physics and Controlled Fusion 49, 675-688<br />
(<strong>2007</strong>).<br />
Bierwage, A., Q. Yu and S. Günter: Large-Mode-Number<br />
Magnetohydrodynamic Instability Driven by Sheared Flows<br />
in a Tokamak Plasma with Reversed Central Shear. Physics<br />
of Plasmas 14, 010704 (<strong>2007</strong>).<br />
Bin, W., A. Bruschi, S. Cirant, V. Erckmann, F. Gandini,<br />
G. Granucci, F. Hollmann, H. P. Laqua, V. Mellera, V. Muzzini,<br />
A. Nardone, F. Noke, B. Piosczyk, F. Purps, T. Rzesnicki,<br />
M. Schmid, C. Sozzi, W. Spies, N. Spinicchia and M. Stoner:<br />
Advances in high power calorimetric matched loads for short<br />
pulses and CW gyrotrons. Fusion Engineering and Design 82,<br />
775-784 (<strong>2007</strong>).<br />
Birus, D., T. Rummel, M. Fricke, K. Petry and H. Demattio:<br />
Development of Quench Detection System for W7-X.<br />
Fusion Engineering and Design 82, 1400-1405 (<strong>2007</strong>).<br />
Bizyukov, I. and K. Krieger: Transition from tungsten erosion<br />
to carbon layer deposition with simultaneous bombardment<br />
of tungsten by helium and carbon. Journal of Applied<br />
Physics 101, 104906 (<strong>2007</strong>).<br />
Bizyukov, I. and K. Krieger: Principal processes occuring at<br />
simultaneous bombardment of tungsten by carbon and deuterium<br />
ions. Journal of Applied Physics 102, 074923 (<strong>2007</strong>).<br />
Bizyukov, I., K. Krieger, A. Azarenkov, S. Levchuk and<br />
C. Linsmeier: Tungsten sputtering and accumulation of implanted<br />
carbon and deuterium by simultaneous bombardment<br />
with D and C ions. Journal of Nuclear Materials 363-365,<br />
1184-1889 (<strong>2007</strong>).<br />
Bobkov, V. V., F. Braun, R. Dux, A. Herrmann, A. Kallenbach,<br />
R. Neu, J.-M. Noterdaeme, T. Pütterich and ASDEX Upgrade<br />
Team: Compatibility of ICRF antennas with W-coated limiters<br />
for different plasma geometries in ASDEX Upgrade.<br />
Journal of Nuclear Materials 363-365, 122-126 (<strong>2007</strong>).<br />
Bohmeyer, W., A. Markin, D. Naujoks, B. Koch, G. Krenz,<br />
M. Baudach and G. Fußmann: Decomposition and sticking<br />
of hydrocarbons in the plasma generator PSI-II. Journal of<br />
Nuclear Materials 363-365, 127-130 (<strong>2007</strong>).<br />
Boscary, J., B. Böswirth, H. Greuner, P. Grigull, M. Missirlian,<br />
A. Plankensteiner, B. Schedler, T. Friedrich, J. Schlosser,<br />
B. Streibl and H. Traxler: Fabrication and testing of W7-X<br />
pre-series target elements. Physica Scripta T128, 195-199<br />
(<strong>2007</strong>).<br />
Publications<br />
120<br />
Boscary, J., B. Böswirth, H. Greuner, M. Missirlian,<br />
B. Schedler, K. Scheiber, J. Schlosser and B. Streibl: Results<br />
of the examinations of the W7-X pre-series target elements.<br />
Fusion Engineering and Design 82, 1634-1638 (<strong>2007</strong>).<br />
Bottino, A., A. G. Peeters, R. Hatzky, S. Jolliet, B. F. McMillan,<br />
T. M. Tran and L. Villard: Nonlinear Low Noise Particle-incell<br />
Simulations of Electron Temperature Gradient Driven<br />
Turbulence. Physics of Plasmas 14, 010701 (<strong>2007</strong>).<br />
Brambilla, M.: Quasilinear Description of Radiofrequencyinduced<br />
Radial Diffusion. Nuclear Fusion 47, 175-180 (<strong>2007</strong>).<br />
Braune, H., P. Brand, V. Erckmann, L. Jonitz, W. Leonhardt,<br />
D. Mellein, G. Michel, G. Müller, F. Purps, K.-H. Schlüter,<br />
M. Winkler, W7-X ECRH Team at <strong>IPP</strong>, W7-X ECRH Team at<br />
IPF and W7-X ECRH Team at FZK: Architecture of central<br />
control system for the 10 MW ECRH-plant at W7-X. Fusion<br />
Engineering and Design 82, 677-685 (<strong>2007</strong>).<br />
Brendel, A., C. Popescu, T. Köck and H. Bolt: Promising composite<br />
heat sink material for the divertor of future fusion reactors.<br />
Journal of Nuclear Materials 367-370, 1476-1480 (<strong>2007</strong>).<br />
Brezinsek, S., A. Pospieszczyk, D. Borodin, M. F. Stamp,<br />
R. Pugno, A. G. McLean, U. Fantz, A. Manhard, A. Kallenbach,<br />
N. H. Brooks, M. Groth, P. Mertens, V. Philipps, U. Samm,<br />
TEXTOR Group, ASDEX Upgrade Group, DIII-D Teams<br />
and JET-EFDA Contributors: Hydrocarbon injection for<br />
quantification of chemical erosion yields in tokamaks.<br />
Journal of Nuclear Materials 363-365, 1119-1128 (<strong>2007</strong>).<br />
Brezinsek, S., R. Pugno, U. Fantz, A. Manhard, H. W. Müller,<br />
A. Kallenbach, P. Mertens and ASDEX Upgrade Team:<br />
Determination of photon efficiencies and hydrocarbon<br />
influxes in the detached outer divertor plasma of ASDEX<br />
Upgrade. Physica Scripta T128, 40-44 (<strong>2007</strong>).<br />
Bronold, F. X., K. Matyash, D. Tskhakaya, R. Schneider and<br />
H. Fehske: Radio-frequency discharges in oxygen: I. Particlebased<br />
modelling. Journal of Physics D 40, 6583-6592 (<strong>2007</strong>).<br />
Budke, M., V. Renken, H. Liebl, G. Rangelov and M. Donath:<br />
Inverse photoemission with energy resolution better than<br />
200 meV. Review of Scientific Instruments 78, 083903 (<strong>2007</strong>).<br />
Busse, A., W.-C. Müller, H. Homann and R. Grauer: Statistics<br />
of passive tracers in three-dimensional magnetohydrodynamic<br />
turbulence. Physics of Plasmas 14, 122303 (<strong>2007</strong>).<br />
Bykov, V., F. Schauer, K. Egorov, P. van Eeten, C. Damiani,<br />
A. Dübner, M. Sochor, L. Sonnerup, A. Capriccioli, A. Tereshchenko,<br />
N. Jaksic, W. Dänner, M. Rumyancev and D. Zacharias:
Structural analysis of W7-X: Main results and critical issues.<br />
Fusion Engineering and Design 82, 1538-1548 (<strong>2007</strong>).<br />
Camenen, Y., A. Pochelon, R. Behn, A. Bottino, A. Bortolon, S. Coda,<br />
A. Karpushov, O. Sauter, G. Zhuang and TCV Team: Impact of<br />
Plasma Trangularity and Collisionality on Electron Heat Transport<br />
in TCV L-mode Plasmas. Nuclear Fusion 47, 510-517 (<strong>2007</strong>).<br />
Cardella, A., B. Hein, D. Hermann, T. Koppe, B. Missal,<br />
D. Pilopp, J. Reich, M. Wanner, H. Jenzsch, R. Krause,<br />
B. Plöckl, G. Di Bartolo, F. Leher, A. Binni, J. Segl, A. Benito,<br />
L. Giordano and S. Langone: Construction of the vacuum vessels<br />
and the magnet supporting structures of Wendelstein 7-X.<br />
Fusion Engineering and Design 82, 1911-1916 (<strong>2007</strong>).<br />
Casati, A., P. Mantica, D. Van Eester, N. Hawkes, F. Imbeaux,<br />
E. Joffrin, A. Marinoni, F. Ryter, A. Salmi, T. Tala, P. De Vries<br />
and JET-EFDA Contributors: Critical temperature gradient<br />
length signatures in heat wave propagation across internal<br />
transport barriers in the Joint European Torus. Physics of<br />
Plasmas 14, 092303 (<strong>2007</strong>).<br />
Chankin, A. V., D. P. Coster, N. Asakura, X. Bonnin, G. D. Conway,<br />
G. Corrigan, S. K. Erents, W. Fundamenski, J. Horacek,<br />
A. Kallenbach, M. Kaufmann, C. Konz, K. Lackner, H. W. Müller,<br />
J. Neuhauser, R. A. Pitts and M. Wischmeier: Discrepancy<br />
between modelled and measured radial electric fields in the<br />
scrape-off layer of divertor tokamaks: a challenge for 2D<br />
fluid codes? Nuclear Fusion 47, 479-489 (<strong>2007</strong>).<br />
Chankin, A. V., D. P. Coster, R. Dux, C. Fuchs, G. Haas,<br />
A. Herrmann, L. D. Horton, A. Kallenbach, M. Kaufmann,<br />
A. S. Kukushkin, K. Lackner, H. W. Müller, J. Neuhauser,<br />
R. Pugno, M. Tsalas and ASDEX Upgrade Team: Comparison<br />
between measured divertor parameters in ASDEX<br />
Upgrade and SOLPS code simulations. Journal of Nuclear<br />
Materials 363-365, 335-340 (<strong>2007</strong>).<br />
Chankin, A. V., D. P. Coster, N. Asakura, G. Corrigan, S. K. Erents,<br />
W. Fundamenski, H. W. Müller, R. A. Pitts, P. C. Stangeby<br />
and M. Wischmeier: A possible role of radial electric field in<br />
driving parallel ion flow in scrape-off layer of divertor<br />
tokamaks. Nuclear Fusion 47, 762-772 (<strong>2007</strong>).<br />
Chen, Y. P., G. S. Xu, J. S. Hu and D. P. Coster: Edge plasma<br />
modelling for HT-7 superconducting tokamak experiments.<br />
Journal of Nuclear Materials 363-365, 544-549 (<strong>2007</strong>).<br />
Coad, J. P., P. Andrew, S. K. Erents, D. E. Hole, J. Likonen,<br />
M. Mayer, R. Pitts, M. Rubel, J. D. Strachan, E. Vainonen-<br />
Ahlgren, A. Widdowson and JET-EFDA Contributros: Erosion<br />
and deposition in the JET MkII-SRP divertor. Journal of<br />
Nuclear Materials 363-365, 287-293 (<strong>2007</strong>).<br />
Publications<br />
121<br />
Colas, L., A. Ekedahl, M. Goniche, J. P. Gunn, B. Nold, Y. Corre,<br />
V. Bobkov, R. Dux, F. Braun, J.-M. Noterdaeme, M.-L. Mayoral,<br />
K. Kirov, J. Mailloux, S. Heuraux, E. Faudot, J. Ongena,<br />
ASDEX Upgrade Team and JET-EFDA Contributors: Understanding<br />
the spatial structure of RF-induced SOL modifications.<br />
Invited Paper. Plasma Physics and Controlled Fusion 49,<br />
B35-B45 (<strong>2007</strong>).<br />
Connor, J. W., C. Angioni, P. H. Diamond, G. W. Hammett,<br />
C. Hidalgo, A. Loarte and P. Mantica: 11 th EU-US Transport<br />
Task Force workshop on transport in fusion plasmas. Nuclear<br />
Fusion 47, 361-369 (<strong>2007</strong>).<br />
Conway, G. D.: <strong>Report</strong> on the Eight International Reflectometry<br />
Workshop (IRW8) (St Petersburg, Russia, 2-4 May <strong>2007</strong>).<br />
Nuclear Fusion 47, 1710-1714 (<strong>2007</strong>).<br />
Coster, D. P., X. Bonnin, A. Mutzke, R. Schneider and M. Warrier:<br />
Integrated modelling of the edge plasma and plasma facing<br />
components. Journal of Nuclear Materials 363-365, 136-139<br />
(<strong>2007</strong>).<br />
Crowley, B., D. Homfray, U. Fantz, D. Boilson and R. S. Hemsworth:<br />
Electron energy distribution function measurements by Langmuir<br />
probe in ITER like negative ion sources. Production and<br />
Neutralization of Negative Ions and Beams. (Ed.) M. P. Stockli.<br />
AIP Conference Proceedings 925. American <strong>Institut</strong>e of Physics,<br />
Melville, NY, 193-207 (<strong>2007</strong>).<br />
Czymek, G., B. Giesen, F. Harberts, A. Panin, M. Lennartz,<br />
U. Reisgen, W. Schuster, J. Wolters, K. Rummel, M. Czerwinski,<br />
H. Lentz and M. Ebner: Design aspects of the joints for the<br />
bus bar system of the Wendelstein 7-X stellarator. Fusion<br />
Engineering and Design 82, 1467-1472 (<strong>2007</strong>).<br />
Da Graça, S., G. D. Conway, P. Lauber, M. Maraschek,<br />
D. Borba, S. Günter, L. Cupido, K. Sassenberg, F. Serra,<br />
M. E. Manso, CFN Reflectometry Group and ASDEX Upgrade<br />
Team: Localization of MHD and fast particle modes using<br />
reflectometry in ASDEX Upgrade. Plasma Physics and Controlled<br />
Fusion 49, 1849-1872 (<strong>2007</strong>).<br />
De Termmerman, G., M. J. Baldwin, R. P. Doerner, D. Nishijima,<br />
R. Seraydarian, K. Schmid, F. Kost, C. Linsmeier and L. Marot:<br />
Beryllium deposition on International Thermonuclear<br />
Experimental Reactor first mirrows: Layer morphology and<br />
influence on mirror reflectivity. Journal of Applied Physics 102,<br />
083302 (<strong>2007</strong>).<br />
Dewar, R. L., B. G. Kenny, C. Nührenberg, T. Tatsuno and<br />
B. F. McMillan: Quantum Chaos? Genericity and Nongenericity<br />
in the MHD Spectrum of Nonaxisymmetric Toroidal Plasmas.<br />
Journal of the Korean Physical Society 50, 112-117 (<strong>2007</strong>).
Dimits, A. M., W. M. Nevins, D. E. Shumaker, G. W. Hammett,<br />
T. Dannert, F. Jenko, M. J. Pueschel, W. Dorland, S. C. Cowley,<br />
J. N. Lebouef, T. L. Rhodes, J. Candy and C. Estrada-Mila:<br />
Gyrokinetic simulations of ETG and ITG turbulence.<br />
Nuclear Fusion 47, 817-824 (<strong>2007</strong>).<br />
Dinklage, A., E. Ascasibar, C. D. Beidler, J. Geiger, J. H. Harris,<br />
A. Kus, S. Murakami, S. Okamura, R. Preuss, F. Sano, U. Stroth,<br />
Y. Suzuki, J. Talmadge, V. Tribaldos, K. Y. Watanabe, H. Yamada<br />
and M. Yokoyama: Assessment of Global Stellarator Confinement:<br />
Status of the International Stellarator Confinement<br />
Scaling Data Base. Fusion Science and Technology 51, 1-7 (<strong>2007</strong>).<br />
Dinklage, A., H. Maaßberg, R. Preuss, Y. Turkin, H. Yamada,<br />
E. Ascasibar, C.D. Beidler, H. Funaba, J. H. Harris, A. Kus,<br />
S. Murakami, S. Okamura, F. Sano, U. Stroth, Y. Suzuki,<br />
J. Talmadge, V. Tribaldos, K. Y. Watanabe, A. Werner, A. Weller<br />
and M. Yokoyama: Physical model assessment of the energy<br />
confinement time scaling in stellarators. Nuclear Fusion 47,<br />
1265-1273 (<strong>2007</strong>).<br />
Dobosz, R., A. Cardella, M. Wanner, G. Dell’Orco and A. Opitz:<br />
The draining and drying experiments for the plasma vessel<br />
cooling pipes of the Wendelstein 7-X stellarator. Fusion<br />
Engineering and Design 82, 2067-2072 (<strong>2007</strong>).<br />
Doerner, R. P., M. Baldwin, J. Hanna, C. Linsmeier, D. Nishijima,<br />
R. Pugno, J. Roth, K. Schmid and A. Wiltner: Interaction of<br />
beryllium containing plasma with ITER materials. Physica<br />
Scripta T128, 115-120 (<strong>2007</strong>).<br />
Donne, A. J. H., A. E. Costley, R. Barnsley, H. Bindslev,<br />
R. Boivin, G. Conway, R. Fisher, R. Gianella, H. Hartfuß,<br />
M. G. von Hellermann, E. Hodgson, L. C. Ingesson, K. Itami,<br />
D. Johnson, Y. Kawano, T. Kondoh, A. Krasilnikov, Y. Kusama,<br />
A. Litnovsky, P. Lotte, P. Nielsen, T. Nishitani, F. Orsitto,<br />
B. J. Peterson, G. Razdobarin, J. Sanchez, M. Sasao, T. Sugie,<br />
G. Vayakis, V. Voitsenya, K. Vukolov, C. Walker, K. Young and<br />
ITPA Topical Group on Diagnostics: Chapter 7: Diagnostics.<br />
Nuclear Fusion 47, S337-S384 (<strong>2007</strong>).<br />
Dose, V.: Bayesian estimate of the Newtonian constant of gravitation.<br />
Measurement Science and Technology 18, 176-182 (<strong>2007</strong>).<br />
Dose, V.: Reply to the comment on “Bayesian estimate of<br />
the Newtonian constant of gravitation”. Measurement Science<br />
and Technology 18, 2281-2282 (<strong>2007</strong>).<br />
Doyle, E. J., W. A. Houlberg, Y. Kamada, V. Mukhovatov,<br />
T. H. Osborne, A. Polevoi, G. Bateman, J. W. Connor,<br />
J. G. Cordey, T. Fujita, X. Garbet, T. S. Hahm, L. D. Horton,<br />
A. E. Hubbard, F. Imbeaux, F. Jenko, J. E. Kinsey, Y. Kishimoto,<br />
J. Li, T. C. Luce, Y. Martin, M. Ossipenko, V. Parail, A. Peeters,<br />
Publications<br />
122<br />
T. L. Rhodes, J. E. Rice, C. M. Roach, V. Rozhansky, F. Ryter,<br />
G. Saibene, R. Sartori, A. C. C. Sips, J. A. Snipes, M. Sugihara,<br />
E. J. Synakowski, H. Takenaga, T. Takizuka, K. Thomsen,<br />
M. R. Wade, H. R. Wilson, ITPA Confinement Database and<br />
Modelling Topical Group and ITPA Pedestal and Edge Topical<br />
Group: Chapter 2: Plasma confinement and transport. Nuclear<br />
Fusion 47, S18-S127 (<strong>2007</strong>).<br />
Dudek, A., A. Benndorf, V. Bykov, A. Cardella, C. Damiani,<br />
A. Dübner, W. Dänner, M. Gasparotto, T. Höschen, G. Matern,<br />
D. Pilopp, F. Schauer, L. Sonnerup, J. Wendorf and C. Zauner:<br />
Tests of the critical bolted connection of the Wendelstein 7-X<br />
coils. Fusion Engineering and Design 82, 1500-1507 (<strong>2007</strong>).<br />
Durocher, A., F. Escourbiac, A. Grosman, J. Boscary, M. Merola,<br />
F. Cismondi, X. Courtois, J. L. Farjon, M. Missirlian, J. Schlosser<br />
and R. Tivey: Advanced qualification methodology for actively<br />
cooled plasma facing components. Nuclear Fusion 47,<br />
1682-1689 (<strong>2007</strong>).<br />
Durocher, A., J. Moysan, F. Escourbiac, M. Missirlian,<br />
N. Vignal and J. Boscary: Infrared images data merging for<br />
plasma-facing component inspection. Fusion Engineering<br />
and Design 82, 1694-1699 (<strong>2007</strong>).<br />
Dux, R., V. Bobkov, N. Fedorczak, K. Iraschko, A. Kallenbach,<br />
R. Neu, T. Pütterich, V. Rohde and ASDEX Upgrade: Tungsten<br />
erosion at the ICRH limiters in ASDEX Upgrade. Journal of<br />
Nuclear Materials 363-365, 112-116 (<strong>2007</strong>).<br />
Eckstein, W.: Sputtering Yields. Sputtering by Particle Bombardment:<br />
Experiments and Computer Calculations from Threshold<br />
to MeV Energies. (Eds.) R. Behrisch, W. Eckstein. Topics in<br />
Applied Physics 110. Springer Verlag, Berlin 33-187 (<strong>2007</strong>).<br />
Eckstein, W. and H. M. Urbassek: Computer Simulation of<br />
the Sputtering Process. Sputtering by Particle Bombardment:<br />
Experiments and Computer Calculations from Threshold to<br />
MeV Energies. (Eds.) R. Behrisch, W. Eckstein. Topics in<br />
Applied Physics 110. Springer Verlag, Berlin 21-31 (<strong>2007</strong>).<br />
Ehmler, H., J. Baldzuhn, L. Genini, K. Heyn, C. Sborchia,<br />
T. Schild and W7-X Team: Review of the acceptance tests of<br />
the W7-X superconducting magnets. Fusion Engineering<br />
and Design 82, 1406-1412 (<strong>2007</strong>).<br />
Ehmler, H. and M. Koeppen: AC modeling and impedance<br />
spectrum tests of the superconducting magnetic field coils<br />
for the Wendelstein 7-X fusion experiment. Review of<br />
Scientific Instruments 78, 104705 (<strong>2007</strong>).<br />
Eich, T., P. Andrew, A. Herrmann, W. Fundamenski, A. Loarte,<br />
R. A. Pitts and JET-EFDA Contributors: ELM resolved
energy distribution studies in the JET MKII Gas-Box divertor<br />
using infra-red thermography. Plasma Physics and Controlled<br />
Fusion 49, 573-604 (<strong>2007</strong>).<br />
Eich, T., A. Kallenbach, R. A. Pitts, S. Jachmich, J. C. Fuchs,<br />
A. Herrmann, J. Neuhauser, ASDEX Upgrade Team and JET-<br />
EFDA Contributors: Divertor power deposition and target current<br />
asymmetries during type-I ELMS in ASDEX Upgrade and<br />
JET. Journal of Nuclear Materials 363-365, 989-993 (<strong>2007</strong>).<br />
Erckmann, V., P. Brand, H. Braune, G. Dammertz, G. Gantenbein,<br />
W. Kasparek, H. P. Laqua, H. Maaßberg, N. B. Marushchenko,<br />
G. Michel, M. Thumm, Y. Turkin, M. Weißgerber, A. Weller,<br />
W7-X ECRH Team and IPF Stuttgart: Electron Cyclotron<br />
Heating for W7-X: Physics and Technology. Fusion Science<br />
and Technology 52, 291-312 (<strong>2007</strong>).<br />
Eule, S., R. Friedrich and F. Jenko: Anomalous Diffusion of<br />
Particles with Inertia in External Potentials. Journal of<br />
Physical Chemistry B 111, 13041-13046 (<strong>2007</strong>).<br />
Eule, S., R. Friedrich, F. Jenko and D. Kleinhans: Langevin<br />
Approach to Fractional Diffusion Equations Including<br />
Inertial Effects. Journal of Physical Chemistry B 111,<br />
11474-11477 (<strong>2007</strong>).<br />
Fantz, U., P. Franzen, W. Kraus, M. Berger, S. Christ-Koch,<br />
M. Fröschle, R. Gutser, B. Heinemann, C. Martens, P. McNeely,<br />
R. Riedl, E. Speth and D. Wünderlich: Negative ion RF<br />
sources for ITER NBI: status of the deveopment and recent<br />
achievements. Invited Paper. Plasma Physics and Controlled<br />
Fusion 49, B563-B580 (<strong>2007</strong>).<br />
Fasoli, A., C. Gormenzano, H. L. Berk, B. Breizman, S. Briguglio,<br />
D. S. Darrow, N. Gorelenkov, W. W. Heidbrink, A. Jaun,<br />
S. V. Konovalov, R. Nazikian, J.-M. Noterdaeme, S. Sharapov,<br />
K. Shinohara, D. Testa, K. Tobita, Y. Todo, G. Vlad and F. Zonca:<br />
Chapter 5: Physics of energetic ions. Nuclear Fusion 47,<br />
S264-S284 (<strong>2007</strong>).<br />
Federici, G., O. Zolotukhin, M. Kobayashi, A. Loarte,<br />
G. Strohmayer, A. Tanga, A. Portone, L. Horton, Y. Feng,<br />
F. Sardei, Y. Gribov, M. Shimada, A. Polevoi, R. Mitteau and<br />
C. Lowry: Simulations of ITER start-up and assessment of<br />
limiter power loads. Journal of Nuclear Materials 363-365,<br />
346-352 (<strong>2007</strong>).<br />
Feifel, R., T. Tanaka, M. Kitajima, H. Tanaka, A. De Fanis,<br />
R. Sankari, L. Karlsson, S. Sorensen, M.-N. Piancastelli,<br />
G. Prümper, U. Hergenhahn and K. Ueda: Probing the<br />
valence character of O 1s → Rydberg excited O 2 by participator<br />
Auger decay and mass-selected X-ray absorption spectroscopy.<br />
Journal of Chemical Physics 126, 174304 (<strong>2007</strong>).<br />
Publications<br />
123<br />
Feist, J.-H., H.-J. Bramow, R. Brockmann, G. Gliege, D. Grünberg,<br />
T. Kluck, D. Pohle, M. Schroeder, R. Schult and R. Vilbrandt:<br />
Quality management for Wendelstein 7-X – Lessons learned.<br />
Fusion Engineering and Design 82, 2838-2843 (<strong>2007</strong>).<br />
Feng, Y., F. Sardei, P. Grigull, K. McCormick, J. Kißlinger,<br />
D. Reiter and D. Harting: Numerical Study on CX-Neutral<br />
Transport and Wall-Sputtering in W7-AS Diverted Plasmas.<br />
Journal of Nuclear Materials 363-365, 353-358 (<strong>2007</strong>).<br />
Fischer, R. and A. Dinklage: The concept of Integrated Data<br />
Analysis of complementary experiments. Bayesian Inference<br />
and <strong>Max</strong>imum Entropy Methods in Science and Engineering:<br />
27 th International Workshop on Bayesian Inference and <strong>Max</strong>imum<br />
Entropy Methods in Science and Engineering. (Eds.)<br />
K. H. Knuth, A. Caticha, J. L. Center, A. Giffin, C. C. Rodriguez.<br />
AIP Conference Proceedings 954. American <strong>Institut</strong>e of<br />
Physics, Melville, NY, 195-202 (<strong>2007</strong>).<br />
Franzen, P., H. D. Falter, U. Fantz, W. Kraus, M. Berger,<br />
S. Christ, M. Fröschle, R. Gutser, B. Heinemann, S. Hilbert,<br />
S. Leyer, A. Lümkemann, C. Martens, P. McNeely, R. Riedl,<br />
E. Speth and D. Wünderlich: Progress of the Development<br />
of the <strong>IPP</strong> RF Negative Ion Source for the ITER Neutral<br />
Beam System. Nuclear Fusion 47, 264-270 (<strong>2007</strong>).<br />
Franzen, P., H. D. Falter, B. Heinemann, Ch. Martens, U. Fantz,<br />
M. Berger, S. Christ-Koch, M. Fröschle, D. Holtum, W. Kraus,<br />
P. McNeely, R. Riedl, R. Süss, S. Obermayer, E. Speth and<br />
D. Wünderlich: RADI – a RF source size-scaling experiment<br />
towards the ITER neutral beam negative ion source.<br />
Fusion Engineering and Design 82, 407-423 (<strong>2007</strong>).<br />
Fröschle, M., S. Leyer, P. Franzen, C. Martens, E. Speth,<br />
B. Heinemann, H. D. Falter, U. Fantz, W. Kraus and R. Riedl:<br />
Technical overview and first results of the half-size ITER<br />
NNBI source. Fusion Engineering and Design 82, 887-896<br />
(<strong>2007</strong>).<br />
Füllenbach, F., T. Rummel, S. Pingel, H. Laqua, I. Müller<br />
and E. Jauregi: Final test of the W7-X control coils power<br />
supply and its integration into the overall control environment.<br />
Fusion Engineering and Design 82, 1391-1395 (<strong>2007</strong>).<br />
Fujisawa, A., T. Ido, A. Shimizu, S. Okamura, K. Matsuoka,<br />
H. Iguchi, Y. Hamada, H. Nakano, S. Ohshima, K. Itoh, K. Hoshino,<br />
K. Shinohara, Y. Miura, Y. Nagashima, S.-I. Itoh, M. Shats,<br />
H. Xia, J. Q. Dong, L. W. Yan, K. J. Zhao, G. D. Conway, U. Stroth,<br />
A. V. Melnikov, L. G. Elisseev, S. E. Lysenko, S. V. Perfilov,<br />
C. Hidalgo, G. R. Tynan, C. Holland, P. H. Diamond, G. R. McKee,<br />
R. J. Fonck, D. K. Gupta and P. M. Schoch: Experimental<br />
progress on zonal flow physics in toroidal plasmas. Nuclear<br />
Fusion 47, S718-S726 (<strong>2007</strong>).
Fundamenski, W., J. Mlynar and M. Wischmeier: Focus On:<br />
Plasma Edge. JET, Culham (<strong>2007</strong>).<br />
http://www.jet.efda.org/pages/focus/plasma-edge/index.html<br />
Gaio, E., W. Kraus, C. Martens, R. Piovan, E. Speth and V. Toigo:<br />
Studies on the radio frequency power supply system for the<br />
ITER NB injector ion source. Fusion Engineering and<br />
Design 82, 912-919 (<strong>2007</strong>).<br />
Garcia-Munoz, M., P. Martin, H.-U. Fahrbach, M. Gobbin,<br />
S. Günter, M. Maraschek, L. Marrelli, H. Zohm and ASDEX<br />
Upgrade Team: NTM induced fast ion losses in ASDEX<br />
Upgrade. Nuclear Fusion 47, L10-L15 (<strong>2007</strong>).<br />
Giesen, B., A. Panin, T. Boguzewski, S. Brons, A. Charl, G. Czymek,<br />
A. John, O. Neubauer, M. Sauer, R. Schick, J. Szlagowska<br />
and J. Wolters: Structural evaluation of the busbar system of<br />
Wendelstein 7-X stellarator. Fusion Engineering and Design 82,<br />
1591-1598 (<strong>2007</strong>).<br />
Goetz, M., R. Meyer-Spasche and H. Weitzner: A study of<br />
simple gyrotron. Journal of Physics A: Mathematical and<br />
Theoretical 40, 2203-2218 (<strong>2007</strong>).<br />
Golubeva, A., M. Mayer, J. Roth, V. Kurnaev and O. Ogorodnikova:<br />
Deuterium retention in rhenium-doped tungsten. Journal of<br />
Nuclear Materials 363-365, 893-897 (<strong>2007</strong>).<br />
Gormezano, C., A. C. C. Sips, T. C. Luce, S. Ide, A. Becoulet,<br />
X. Litaudon, A. Isayama, J. Hobirk, M. R. Wade, T. Oikawa,<br />
R. Prater, A. Zvonkov, B. Lloyd, T. Suzuki, E. Barbato, P. Bonoli,<br />
C. K. Phillips, V. Vdovin, E. Joffrin, T. Casper, J. Ferron,<br />
D. Mazon, D. Moreau, R. Bundy, C. Kessel, A. Fukuyama,<br />
N. Hayashi, F. Imbeaux, M. Murakami, A. R. Polevoi and<br />
H. E. St John: Chapter 6: Steady state operation. Nuclear<br />
Fusion 47, S285-S336 (<strong>2007</strong>).<br />
Grandgiard, V., Y. Sarazin, P. Angelino, A. Bottino, N. Crouseilles,<br />
G. Darmet, G. Dif-Pradalier, X. Garbet, P. Ghendrih, S. Jolliet,<br />
G. Latu, E. Sonnendrücker and L. Villard: Global full-f<br />
gyrokinetic simulations of plasma turbulence. Invited Paper.<br />
Plasma Physics and Controlled Fusion 49, B173-B182 (<strong>2007</strong>).<br />
Greuner, H., B. Boeswirth, J. Boscary, A. Leuprecht and<br />
A. Plankensteiner: Power load limits of the Wendelstein 7-X<br />
target elements – comparison of experimental results and<br />
design values for power loads up to the critical heat flux.<br />
Physica Scripta T128, 218-221 (<strong>2007</strong>).<br />
Greuner, H., B. Boeswirth, J. Boscary and P. McNeely: High<br />
Heat Flux Facility GLADIS – Operational Characteristics<br />
and Results of W7-X Pre-Series Target Tests. Journal of<br />
Nuclear Materials 367-370, 1444-1448 (<strong>2007</strong>).<br />
Publications<br />
124<br />
Greuner, H., B. Boeswirth, J. Boscary, A. Plankensteiner<br />
and B. Schedler: High heat flux tests of the Wendelstein 7-X<br />
pre-series target elements – Experimental evaluation of the<br />
thermo-mechanical behaviour. Fusion Engineering and<br />
Design 82, 1713-1719 (<strong>2007</strong>).<br />
Gribov, Y., D. Humphreys, K. Kajiwara, E. A. Lazarus, J. B. Lister,<br />
T. Ozeki, A. Portone, M. Shimada, A. C. C. Sips and J. C. Wesley:<br />
Chapter 8: Plasma operation ans control. Nuclear Fusion 47,<br />
S385-S403 (<strong>2007</strong>).<br />
Grisolia, C., G. Counsell, G. Dinescu, A. Semerok, N. Bekris,<br />
P. Coad, C. Hopf, J. Roth, M. Rubel, A. Widdowson, E. Tsitrone<br />
and JET EFDA Contributors: Treatment of ITER plasma<br />
facing components: Current status and remaining open<br />
issues before ITER implementation. Fusion Engineering<br />
and Design 82, 2390-2398 (<strong>2007</strong>).<br />
Gruber, O. and ASDEX Upgrade Team: Overview of ASDEX<br />
Upgrade Results. Nuclear Fusion 47, S622-S634 (<strong>2007</strong>).<br />
Grulke, O., A. Stark, T. Windisch, J. Zalach and T. Klinger:<br />
Plasma profiles in a cylindrical helicon discharge with converging<br />
magnetic source field. Contributions to Plasma<br />
Physics 47, 183-189 (<strong>2007</strong>).<br />
Grulke, O., S. Ulrich, T. Windisch and T. Klinger: Laboratory<br />
studies of drift waves: nonlinear mode interaction and<br />
structure formation in turbulence. Invited Paper. Plasma<br />
Physics and Controlled Fusion 49, B247-B257 (<strong>2007</strong>).<br />
Günter, S., G. Conway, S. da Graca, H.-U. Fahrbach, C. Forest,<br />
M. Garcia Munoz, T. Hauff, J. Hobirk, V. Igochine, F. Jenko,<br />
K. Lackner, P. Lauber, P. McCarthy, M. Maraschek, P. Martin,<br />
E. Poli, K. Sassenberg, E. Strumberger, G. Tardini, E. Wolfrum,<br />
H. Zohm and ASDEX Upgrade Team: Interaction of energetic<br />
particles with large and small scale instabilities. Nuclear<br />
Fusion 47, 920-928 (<strong>2007</strong>).<br />
Günter, S. and K. Lackner: Wie bändigt man heißes Plasma?<br />
Plasmaeinschluss in Fusionsexperimenten. Physik in unserer<br />
Zeit 38, 134-140 (<strong>2007</strong>).<br />
Günter, S., K. Lackner and C. Tichmann: Finite element and<br />
higher order difference formulations for modelling heat<br />
transport in magnetised plasmas. Journal of Computational<br />
Physics 226, 2306-2316 (<strong>2007</strong>).<br />
Gulejova, B., R. A. Pitts, M. Wischmeier, R. Behn, D. Coster,<br />
J. Horacek and J. Marki: SOLPS5 modelling of the type III<br />
ELMing H-mode on TCV. Journal of Nuclear Materials<br />
363-365, 1037-1053 (<strong>2007</strong>).
Hacquin, S., S. E. Sharapov, B. Alper, C. D. Challis, A. Fonseca,<br />
E. Mazzucato, A. Meigs, L. Meneses, I. Nunes, S. D. Pinches<br />
and JET EFDA Contributors: Localized X-mode reflectometry<br />
measurements of Alfvén eigenmodes on the JET tokamak.<br />
Plasma Physics and Controlled Fusion 49, 1371-1390 (<strong>2007</strong>).<br />
Hallatschek, K.: Nonlinear three-dimensional flows in magnetized<br />
plasmas. Invited Paper. Plasma Physics and Controlled<br />
Fusion 49, B137-B148 (<strong>2007</strong>).<br />
Hartmann, D. A., R. Krampitz, C. Damiani, U. Neuner and<br />
F. Schauer: Wendelstein 7-X Torus Hall Layout and System<br />
Integration. Fusion Engineering and Design 82, 583-589 (<strong>2007</strong>).<br />
Hatzky, R., A. Könies and A. Mishchenko: Electromagnetic<br />
gyrokinetic PIC simulation with an adjustable control variates<br />
method. Journal of Computational Physics 225, 568-590 (<strong>2007</strong>).<br />
Hauff, T. and F. Jenko: E×B advection of trace ions in tokamak<br />
microturbulence. Physics of Plasmas 14, 092301 (<strong>2007</strong>).<br />
Hauff, T., F. Jenko and S. Eule: Intermediate non-Gaussian<br />
transport in plasma core turbulence. Physics of Plasmas 14,<br />
102316 (<strong>2007</strong>).<br />
Hayashi, T., K. Sugiyama, K. Krieger, M. Mayer, V. Alimov,<br />
T. Tanabe, K. Masaki and N. Miya: Deuterium depth profiling<br />
in JT-60U tiles using the D 3 (He,p) 4 He resonant nuclear<br />
reaction. Journal of Nuclear Materials 363-365, 904-909<br />
(<strong>2007</strong>).<br />
Heidinger, R., I. Danilov, A. Meier, B. Piosczyk, B. Späh,<br />
M. Thumm, W. Bongers, M. Graswinckel, M. Henderson,<br />
F. Leuterer, A. G. A. Verhoeven and D. Wagner: Development<br />
of high power window prototypes for ECH&CD launchers.<br />
Fusion Engineering and Design 82, 693-699 (<strong>2007</strong>).<br />
Helander, P.: On rapid rotation in stellarators. Physics of<br />
Plasmas 14, 104501 (<strong>2007</strong>).<br />
Hender, T. C., J. C. Wesley, J. Bialek, A. Bondeson, A. H. Boozer,<br />
R. J. Buttery, A. Garofalo, T. P. Goodman, R. S. Granetz, Y. Gribov,<br />
O. Gruber, M. Gryaznevich, G. Giruzzi, S. Günter, N. Hayashi,<br />
P. Helander, C. C. Hegna, D. F. Howell, D. A. Humphreys,<br />
G. T. A. Huysmans, A. W. Hyatt, A. Isayama, S. C. Jardin,<br />
Y. Kawano, A. Kellman, C. Kessel, H. R. Koslowski, R. J. La Haye,<br />
E. Lazzaro, Y. Q. Liu, V. Lukash, J. Manickam, S. Medvedev,<br />
V. Mertens, S. V. Mirnov, Y. Nakamura, G. Navratil, M. Okabayashi,<br />
T. Ozeki, R. Paccagnella, G. Pautasso, F. Porcelli, V. D. Pustovitov,<br />
V. Riccardo, M. Sato, O. Sauter, M. J. Schaffer, M. Shimada,<br />
P. Sonato, E. J. Strait, M. Sugihara, M. Takechi, A. D. Turnbull,<br />
E. Westerhof, D. G. Whyte, R. Yoshino, H. Zohm and ITPA<br />
MHD, Disruption and Magnetic Control Topical Group:<br />
Publications<br />
125<br />
Chapter 3: MHD stability, operational limits and disruptions.<br />
Nuclear Fusion 47, S128-S202 (<strong>2007</strong>).<br />
Henderson, M. A., S. Albert, P. Benin, T. Bonicelli, R. Chavan,<br />
D. Campbell, S. Cirant, G. Dammertz, O. Dormicchi, O. Dumbrajs,<br />
D. Fasel, T. P. Goodman, R. Heidinger, J.-P. Hogge, W. Kasparek,<br />
C. Lievin, B. Piosczyk, E. Poli, G. Ramponi, G. Saibene, O. Sauter,<br />
A. Serikov, G. Taddia, M. Thumm, M. Q. Tran, A. G. A. Verhoevenk<br />
and H. Zohm: EU developments of the ITER ECRH system.<br />
Fusion Engineering and Design 82, 454-462 (<strong>2007</strong>).<br />
Herrmann, A.: Surface temperature measurement and heat<br />
load estimation for carbon targets with plasma contact and<br />
machine protection. Physica Scripta T128, 234-238 (<strong>2007</strong>).<br />
Herrmann, A., A. Brendel, M. Balden and H. Bolt: Metal<br />
Matrix Composite used as high-temperature heat sink material<br />
for future fusion reactors. JEC Composite Magazine, 33,<br />
67-70 (<strong>2007</strong>).<br />
Herrmann, A., A. Kirk, A. Schmid, B. Koch, M. Laux, M. Maraschek,<br />
H. W. Müller, J. Neuhauser, V. Rohde, M. Tsalas and E. Wolfrum:<br />
The filamentary structure of ELMs in the scrape-off layer in<br />
ASDEX Upgrade. Journal of Nuclear Materials 363-365,<br />
528-533 (<strong>2007</strong>).<br />
Hildebrandt, D. and A. Dübner: Thermal response of structural<br />
and contaminated carbon surfaces to heat pulses.<br />
Journal of Nuclear Materials 363-365, 1221-1225 (<strong>2007</strong>).<br />
Hirai, T., H. Maier, M. Rubel, P. Mertens, R. Neu, E. Gauthier,<br />
J. Likonen, C. Lungu, C. Maddaluno, G. Matthews, R. Mitteau,<br />
O. Neubauer, G. Piazza, V. Philipps, B. Riccardi, C. Ruset,<br />
I. Uytdenhouwen and JET-EFDA Contributors: R&D on full<br />
tungsten divertor and beryllium wall for JET ITER-like Wall<br />
Project. Fusion Engineering and Design 82, 1839-1845 (<strong>2007</strong>).<br />
Hölzl, M., S. Günter, Q. Yu and K. Lackner: Numerical modeling<br />
of diffusive heat transport across magnetic islands and highly<br />
stochastic layers. Physics of Plasmas 14, 052501 (<strong>2007</strong>).<br />
Homann, H., R. Grauer, A. Busse and W.-C. Müller:<br />
Lagrangian statistics of Navier-Stokes and MHD Turbulence.<br />
Journal of Plasma Physics 73, 6, 821-830 (<strong>2007</strong>).<br />
Hopf, C., V. Rohde, W. Jacob, A. Herrmann, R. Neu, J. Roth<br />
and ASDEX Upgrade Team: Oxygen glow discharge cleaning<br />
in ASDEX Upgrade. Journal of Nuclear Materials 363-365,<br />
882-887 (<strong>2007</strong>).<br />
Hopf, C., M. Schlüter and W. Jacob: Chemical sputtering of<br />
carbon films by argon ions and molecular oxygen at cryogenic<br />
temperatures. Applied Physics Letters 90, 224106 (<strong>2007</strong>).
Hoshino, K., A. Hatayama, N. Asakura, H. Kawashima,<br />
R. Schneider and D. Coster: Numerical analysis of the<br />
SOL/divertor plasma flow with the effect of drifts. Journal<br />
of Nuclear Materials 363-365, 539-543 (<strong>2007</strong>).<br />
Huber, A., K. McCormick, P. Andrew, P. Beaumont, S. Dalley,<br />
J. Fink, J. C. Fuchs, K. Fullard, W. Fundamenski, L. C. Ingesson,<br />
F. Mast, A. Jachmich, G. F. Matthews, P. Mertens, V. Philipps,<br />
R. A. Pitts, S. Sanders, W. Zeidner and JET-EFDA Contributors:<br />
Upgraded bolometer system on JET for improved radiation measurements.<br />
Fusion Engineering and Design 82, 1327-1334 (<strong>2007</strong>).<br />
Huber, A., K. McCormick, P. Andrew, M. R. de Baar, P. Beaumont,<br />
S. Dalley, J. Fink, J. C. Fuchs, K. Fullard, W. Fundamenski,<br />
L. C. Ingesson, G. Kirnev, P. Lomas, F. Mast, S. Jachmich,<br />
G. F. Matthews, P. Mertens, A. Meigs, V. Philipps, J. Rapp,<br />
G. Saibene, S. Sanders, R. Sartori, M. F. Stamp, W. Zeidner<br />
and JET-EFDA Contributors: Improved radiation measurements<br />
on JET – First results from an upgraded bolometer system.<br />
Journal of Nuclear Materials 363-365, 365-370 (<strong>2007</strong>).<br />
Hynönen, V. and T. Kurki-Suonio: Erratum on Surface<br />
Loads and Edge Fast Ion Distribution for Co- and Counterinjection<br />
in ASDEX Upgrade. Plasma Physics and Controlled<br />
Fusion 49, 1345-1347 (<strong>2007</strong>).<br />
Hynönen, V., T. Kurki-Suonio, W. Suttrop, R. Dux, K. Sugiyama<br />
and ASDEX Upgrade Team: Surface loads and edge fast ion<br />
distribution for co- and counter-injection in ASDEX Upgrade.<br />
Plasma Physics and Controlled Fusion 49, 151-174 (<strong>2007</strong>).<br />
Igochine, V., O. Dumbrajs, H. Zohm, A. Flaws and ASDEX<br />
Upgrade Team: Stochastic sawtooth reconnection in ASDEX<br />
Upgrade. Nuclear Fusion 47, 23-32 (<strong>2007</strong>).<br />
Jachmich, S., T. Eich, W. Fundamenski, A. Kallenbach, R. A. Pitts<br />
and JET-EFDA Contributors: Divertor particle and power<br />
deposition profiles in JET ELMY H-mode discharges.<br />
Journal of Nuclear Materials 363-365, 1050-1055 (<strong>2007</strong>).<br />
Jacob, W. and J. Roth: Chemical Sputtering. Sputtering by<br />
Particle Bombardment: Experiments and Computer Calculations<br />
from Threshold to MeV Energies. (Eds.) R. Behrisch,<br />
W. Eckstein. Topics in Applied Physics 110. Springer Verlag,<br />
Berlin, 329-400 (<strong>2007</strong>).<br />
Jolliet, S., A. Bottino, P. Angelino, R. Hatzky, T. M. Tran,<br />
B. F. Mcmillan, O. Sauter, K. Appert, Y. Idomura and L. Villard:<br />
A global collisionless PIC code in magnetic coordinates.<br />
Computer Physics Communications 177, 409-425 (<strong>2007</strong>).<br />
Joseph, I., R. A. Moyer, T. E. Evans, M. J. Schaffer, A. M. Runov,<br />
R. Schneider, S. V. Kasilov, M. Groth and M. E. Fenstermacher:<br />
Publications<br />
126<br />
Stochastic transport modeling of resonant magnetic perturbations<br />
in DIII-D. Journal of Nuclear Materials 363-365,<br />
591-595 (<strong>2007</strong>).<br />
Kallenbach, A., R. Dux, J. Harhausen, C. F. Maggi, R. Neu,<br />
T. Pütterich, V. Rohde, K. Schmid, E. Wolfrum and ASDEX<br />
Upgrade Team: Spectroscopic investigation of carbon<br />
migration with tungsten walls in ASDEX Upgrade. Journal<br />
of Nuclear Materials 363-365, 60-65 (<strong>2007</strong>).<br />
Kamiya, K., N. Asakura, J. Boedo, T. Eich, G. Federici,<br />
M. Fenstermacher, K. Finken, A. Herrmann, J. Terry, A. Kirk,<br />
B. Koch, A. N. Loarte, R. Maingi, R. Maqueda, E. Nardon,<br />
N. Oyama and R. Sartori: Edge localized modes: recent<br />
experimental findings and related issues. Plasma Physics<br />
and Controlled Fusion 49, S43-S62 (<strong>2007</strong>).<br />
Kasparek, W., M. Petelin, V. Erckmann, D. Shchegolkov,<br />
A. Bruschi, S. Cirant, A. Litvak, M. Thumm, B. Plaum,<br />
M. Grünert, M. Malthaner, ECRH Groups at <strong>IPP</strong> Greifswald,<br />
FZK Karlsruhe and IPF Stuttgart: Fast switching and<br />
power combination of high-power electron cyclotron wave<br />
beams: principles, numerical results and experiments. Fusion<br />
Science and Technology 52, 281-290 (<strong>2007</strong>).<br />
Kaufmann, M. and R. Neu: Tungsten as first wall material in<br />
fusion devices. Invited. Fusion Engineering and Design 82,<br />
521-527 (<strong>2007</strong>).<br />
Kessel, C. E., G. Giruzzi, A. C. C. Sips, R. V. Budny, J. F. Artaud,<br />
V. Basiuk, F. Imbeaux, E. Joffrin, M. Schneider, M. Murakami,<br />
T. Luce, H. St John, T. Oikawa, N. Hayashi, T. Takizuka, T. Ozeki,<br />
Y.-S. Na, J. M. Park, J. Garcia and A. A. Tucillo: Simulation<br />
of the hybrid and steady state advanced operating modes in<br />
ITER. Nuclear Fusion 47, 1274-1284 (<strong>2007</strong>).<br />
Kizu, K., K. Tsuchiya, T. Ando, C. Sborchia, K. Masaki, S. Sakurai,<br />
A. M. Sukegawa, H. Tamai, T. Fujita, M. Matsukawa, Y. Miura<br />
and M. Kikuchi: Conceptual Design of Magnet System for<br />
JT-60 Super Advanced (JT-60SA). IEEE Transactions on<br />
Applied Superconductivity 17, 1348-1352 (<strong>2007</strong>).<br />
Kobayashi, M., Y. Feng, A. Loarte, G. Federici, G. Strohmayer,<br />
M. Shimada, F. Sardei, D. Reiter and M. Sugihara: 3D<br />
edge transport analysis of ITER start-up configuration for<br />
limiter power load assessment. Nuclear Fusion 47, 61-73<br />
(<strong>2007</strong>).<br />
Kobayashi, M., Y. Feng, S. Masuzaki, M. Shoji, J. Miyazawa,<br />
T. Morisaki, N. Oyabu, N. Ashikawa, A. Komori, O. Motojima,<br />
LHD Experimental Group, Y. Igitkhanov, F. Sardei and<br />
D. Reiter: Divertor transport study in the large helical device.<br />
Journal of Nuclear Materials 363-365, 294-300 (<strong>2007</strong>).
Kobayashi, M., N. Ohyabu, T. Mutoh, R. Kumazawa, Y. Feng,<br />
M. Shoji, T. Morisaki, S. Masuzaki, A. Sagara, R. Sakamoto,<br />
T. Seki, J. Miyazawa, T. Watanabe, M. Goto, K. Ikeda,<br />
H. Kasahara, S. Morita, B.J. Peterson, N. Ashikawa, K. Saito,<br />
S. Sakakibara, T. Tokuzawa, Y. Nakamura, K. Narihara, L. Yamada,<br />
H. Yamada, A. Komori, O. Motojima and LHD Experimental<br />
Group: Edge transport control with the local island divertor and<br />
recent progress in LHD. Fusion Science and Technology 52,<br />
566-573 (<strong>2007</strong>).<br />
Koch, B., A. Herrmann, A. Kirk, H. Meyer, J. Dowling,<br />
J. Harhausen, J. Neuhauser, H. W. Müller, W. Bohmeyer,<br />
G. Fußmann, AUG Team and MAST Team: Observation of<br />
ELM structures in MAST and AUG using a fast camera.<br />
Journal of Nuclear Materials 363-365, 1056-1060 (<strong>2007</strong>).<br />
Koch, F. and H. Bolt: Self Passivating W-based Alloys as<br />
Plasma Facing Materials for Nuclear Fusion. Physica<br />
Scripta T128, 100-105 (<strong>2007</strong>).<br />
Koch, F., R. Nocentini, B. Heinemann, S. Lindig, P. Junghanns<br />
and H. Bolt: MoS2 coatings for the narrow support elements<br />
of the W-7X non planar coils. Fusion Engineering and<br />
Design 82, 1614-1620 (<strong>2007</strong>).<br />
Kocsis, G., S. Kalvin, P. T. Lang, M. Maraschek, J. Neuhauser,<br />
W. Schneider, T. Szepesi and ASDEX Upgrade Team: Spatiotemporal<br />
investigations on the triggering of pellet induced<br />
ELMs. Nuclear Fusion 47, 1166-1175 (<strong>2007</strong>).<br />
Köck, T., A. Brendel and H. Bolt: Interface reactions between<br />
silicon carbide and interlayers in silicon carbide-copper<br />
metal-matrix composites. Journal of Nuclear Materials 362,<br />
197-201 (<strong>2007</strong>).<br />
Köppen, M. and J. Kißlinger: Simulation of Voltage and<br />
Current Development in the Wendelstein 7-X Coil System<br />
Taking into Account Fault Conditions. Fusion Engineering<br />
and Design 82, 1549-1554 (<strong>2007</strong>).<br />
Kolesnichenko, Y., V. Lutsenko, V. S. Marchenko, A. Weller,<br />
R. B. White, Y. V. Yakovenko and K. Yamazaki: Magnetohydrodynamic<br />
activity and energetic ions in fusion plasmas.<br />
Plasma Physics and Controlled Fusion 49, A159-A166 (<strong>2007</strong>).<br />
Kolesnichenko, Ya. I., V. V. Lutsenko, A. Weller, A. Werner,<br />
Yu. V. Yakovenko, J. Geiger and O. P. Fesenyuk: Conventional<br />
and non-conventional global Alfvén eigenmodes in<br />
stellarators. Physics of Plasmas 14, 102504 (<strong>2007</strong>).<br />
Kolev, S., S. Lishev, A. Shivarova, K. Tarnev and R. Wilhelm:<br />
Magnetic filter operation in hydrogen plasmas. Plasma<br />
Physics and Controlled Fusion 49, 1349-1369 (<strong>2007</strong>).<br />
Publications<br />
127<br />
Kraus, W., P. McNeely, M. Berger, S. Christ-Koch, H. D. Falter,<br />
U. Fantz, P. Franzen, M. Fröschle, B. Heinemann, S. Leyer,<br />
R. Riedl, E. Speth and D. Wünderlich: RF Negative Ion<br />
Source Development at <strong>IPP</strong> Garching. Production and Neutralization<br />
of Negative Ions and Beams. (Ed.) M. P. Stockli.<br />
AIP Conference Proceedings 925. American <strong>Institut</strong>e of<br />
Physics, Melville, NY, 224-237 (<strong>2007</strong>).<br />
Kreter, A., A. Kirschner, P. Wienhold, J. Likonen, M. Mayer,<br />
V. Philipps, U. Samm and TEXTOR Team: Long-Term<br />
Erosion and Deposition Studies of the Main Graphite<br />
Limiter in TEXTOR. Physica Scripta T128, 35-39 (<strong>2007</strong>).<br />
Krieger, K., W. Jacob, D. Rudakov, R. Bastasz, G. Federici,<br />
A. Litnovsky, H. Maier, V. Rohde, G. Strohmayer, W. West,<br />
J. Whaley, C. Wong, ASDEX Upgrade Team and DIII-D Teams:<br />
Formation of deuterium-carbon inventories in gaps of plasma<br />
facing components. Journal of Nuclear Materials 363-365,<br />
870-876 (<strong>2007</strong>).<br />
Kukushkin, A. S., H. D. Pacher, V. Kotov, D. Reiter, D. Coster<br />
and G. W. Pacher: Effect of conditions for gas recirculation<br />
on divertor operation in ITER. Nuclear Fusion 47, 698-705<br />
(<strong>2007</strong>).<br />
Kukushkin, A. S., H. D. Pacher, V. Kotov, D. Reiter, D. P. Coster<br />
and G. W. Pacher: Effect of the dome on divertor performance<br />
in ITER. Journal of Nuclear Materials 363-365,<br />
308-313 (<strong>2007</strong>).<br />
Kurzan, B., L. D. Horton, H. D. Murmann, J. Neuhauser,<br />
W. Suttrop and ASDEX Upgrade Team: Thomson scattering<br />
analysis of large scale fluctuations in the ASDEX Upgrade<br />
edge. Plasma Physics and Controlled Fusion 49, 825-844<br />
(<strong>2007</strong>).<br />
Lang, P., P. Cierpka, J. Harhausen, J. Neuhauser, C. Wittmann,<br />
ASDEX Upgrade Team, K. Gal, S. Kalvin, G. Kocsis, J. Sarkozi,<br />
T. Szepesi, C. Dorner and G. Kauke: Cryogenic pellet launcher<br />
adapted for controlling of tokamak plasma edge instabilities.<br />
Review of Scientific Instruments 78, 023504 (<strong>2007</strong>).<br />
Lang, P. T., B. Alper, R. Buttery, K. Gal, J. Hobirk, J. Neuhauser,<br />
M. Stamp and JET EFDA Contributors: ELM triggering by<br />
local pellet perturbations in type-I ELMy H-mode plasma at<br />
JET. Nuclear Fusion 47, 754-761 (<strong>2007</strong>).<br />
Lang, P. T., P. Cierpka, J. Harhausen, M. Kaufmann, J. Neuhauser,<br />
C. Wittmann, G. Kocsis, J. Sárközi, T. Szepesi, C. Dorner,<br />
G. Kauke and ASDEX Upgrade Team: A pellet launcher tool<br />
optimized for the control of edge localized modes in ASDEX<br />
Upgrade H-mode plasmas. Fusion Engineering and Design 82,<br />
1073-1080 (<strong>2007</strong>).
Laqua, H., J. Schacht and A. Spring: Runtime resource<br />
checking at Wendelstein 7-X during plasma operation. Fusion<br />
Engineering and Design 82, 982-987 (<strong>2007</strong>).<br />
Laqua, H. P.: Electron Bernstein Wave Heating and Diagnostic<br />
(Review article). Plasma Physics and Controlled Fusion 49,<br />
R1-R42 (<strong>2007</strong>).<br />
Lauber, P., S. Günter, A. Könies and S. D. Pinches: LIGKA:<br />
A linear gyrokinetic code for the description of background<br />
kinetic and fast particle effects on the MHD stability in<br />
tokamaks. Journal of Computational Physics 226, 447-465<br />
(<strong>2007</strong>).<br />
Lazaros, A., M. Maraschek and H. Zohm: A model for the<br />
advantage of early electron cyclotron current drive in the suppression<br />
of neoclassical tearing modes. Physics of Plasmas 14,<br />
042505 (<strong>2007</strong>).<br />
Levchuk, D.: Plasma assisted techniques for deposition of<br />
superhard nanocomposite coatings. Surface and Coatings<br />
Technology 201, 6071-6077 (<strong>2007</strong>).<br />
Levchuk, D., S. Levchuk, H. Maier, H. Bolt and A. Suzuki:<br />
Erbium oxide as a new promising tritium permeation barrier.<br />
Journal of Nuclear Materials 367-370, 1033-1037 (<strong>2007</strong>).<br />
Levchuk, S., S. Lindig, A. Brendel and H. Bolt: Interface<br />
reactions and control of diffusion at the interface between<br />
SiC fibres and layer of deposited Fe-9Cr base alloy. Journal<br />
of Nuclear Materials 367-370, 1233-1237 (<strong>2007</strong>).<br />
Liang, Y., H. R. Koslowski, P. R. Thomas, E. Nardon, S. Jachmich,<br />
B. Alper, P. Andrew, Y. Andrew, G. Arnoux, Y. Baranov,<br />
M. Becoulet, M. Beurskens, T. Biewer, M. Bigi, K. Crombe,<br />
E. De La Luna, P. de Vries, T. Eich, H. G. Esser, W. Fundamenski,<br />
S. Gerasimov, C. Giroud, M. P. Gryaznevich, D. Harting,<br />
N. Hawkes, S. Hotchin, D. Howell, A. Huber, M. Jakubowski,<br />
V. Kiptily, A. Kreter, L. Moreira, V. Parail, S. D. Pinches,<br />
E. Rachlew, O. Schmitz, O. Zimmermann and JET EFDA<br />
Contributors: Active control of type-I edge localized modes on<br />
JET. Invited Paper. Plasma Physics and Controlled Fusion 49,<br />
B581-B589 (<strong>2007</strong>).<br />
Liang, J. H., M. Mayer, J. Roth, M. Balden and W. Eckstein:<br />
Hydrogen isotopic effects on the chemical erosion of graphite<br />
induced by ion irradiation. Journal of Nuclear Materials<br />
363-365, 184-189 (<strong>2007</strong>).<br />
Linsmeier, C., K. Ertl, J. Roth, A. Wiltner, K. Schmid, F. Kost,<br />
S. Bhattacharyya, M. Baldwin and R. Doerner: Binary<br />
beryllium-tungsten mixed materials. Journal of Nuclear<br />
Materials 363-365, 1129-1137 (<strong>2007</strong>).<br />
Publications<br />
128<br />
Lipschultz, B., X. Bonnin, G. Counsell, A. Kallenbach,<br />
A. Kukushkin, K. Krieger, A. Leonard, A. Loarte, R. Neu,<br />
A. Pitts, T. Rognlien, J. Roth, C. Skinner, J. L. Terry, E. Tsitrone,<br />
D. Whyte, S. Zweben, N. Asakura, D. Coster, R. Doerner, R. Dux,<br />
G. Federici, M. Fenstermacher, W. Fundamenski, P. Ghendri,<br />
A. Herrmann, J. Hu, S. Krasheninnikov, G. Kirnev, A. Kreter,<br />
V. Kurnaev, B. LaBombard, S. Lisgo, T. Nakano, N. Ohno,<br />
H. D. Pacher, J. Paley, Y. Pan, G. Pautasso, V. Philipps, V. Rohde,<br />
D. Rudakov, P. Stangeby, S. Takamura, T. Tanabe, Y. Yang<br />
and S. Zhu: Plasma-surface interaction, scrape-off layer and<br />
divertor physics: implications for ITER. Nuclear Fusion 47,<br />
1189-1205 (<strong>2007</strong>).<br />
Litaudon, X., G. Arnoux, M. Beurskens, S. Brezinsek, C. D. Challis,<br />
F. Crisanti, P. C. De Vries, C. Giroud, R. A. Pitts, F. G. Rimini,<br />
Y. Andrew, Y. F. Baranov, M. Brix, P. Buratti, R. Cesario,<br />
Y. Corre, E. De La Luna, W. Fundamenski, E. Giovannozzi,<br />
M. P. Gryaznevich, N. C. Hawkes, J. Hobirk, A. Huber,<br />
S. Jachmich, E. Joffrin, H. R. Koslowski, Y. Liang, T. Loarer,<br />
P. Lomas, T. Luce, J. Mailloux, G. F. Matthews, K. McCormick,<br />
D. Mazon, D. Moreau, V. Pericoli, V. Philipps, E. Rachlew,<br />
S. D. A. Reyes-Cortes, G. Saibene, S. E. Sharapov, I. Voitsekovitch,<br />
L. Zabeo, O. Zimmermann, K. D. Zatrow and JET-EFDA<br />
Contributors: Development of steady-state scenarios compatible<br />
with ITER-like wall conditions. Invited Paper. Plasma<br />
Physics and Controlled Fusion 49, B529-B550 (<strong>2007</strong>).<br />
Litnovsky, A., V. Philipps, A. Kirschner, P. Wienhold,<br />
G. Sergienko, A. Kreter, U. Samm, O. Schmitz, K. Krieger,<br />
P. Karduck, M. Blome, B. Emmoth, M. Rubel, U. Breuer and<br />
A. Scholl: Carbon transport, deposition and fuel accumulation<br />
in castellated structures exposed in TEXTOR. Journal<br />
of Nuclear Materials 367-370, 1481-1486 (<strong>2007</strong>).<br />
Litnovsky, A., V. Philipps, P. Wienhold, K. Krieger, G. Sergienko,<br />
A. Kreter, O. Schmitz, U. Samm, P. Mertens, A. Kirschner,<br />
S. Droste, S. Richter, U. Breuer, A. Scholl, A. Besmehn and<br />
Y. Xu: Castellated structures for ITER: the influence of the<br />
shape of castellation on the impurity deposition and fuel<br />
accumulation in gaps. Physica Scripta T128, 45-49 (<strong>2007</strong>).<br />
Loarer, T., C. Brosset, J. Bucalossi, P. Coad, G. Esser, J. Hogan,<br />
J. Likonen, M. Mayer, P. Morgan, V. Philipps, V. Rohde, J. Roth,<br />
M. Rubel, E. Tsitrone, A. Widdowson and JET EFDA Contributors:<br />
Gas balance and fuel retention in fusion devices.<br />
Nuclear Fusion 47, 1112-1120 (<strong>2007</strong>).<br />
Loarte, A., B. Lipschultz, A. S. Kukushkin, G. F. Matthews,<br />
P. C. Stangeby, N. Asakura, G. F. Counsell, G. Federici,<br />
A. Kallenbach, K. Krieger, A. Mahdavi, V. Philipps, D. Reiter,<br />
J. Roth, J. Strachan, D. Whyte, R. Doerner, T. Eich, W. Fundamenski,<br />
A. Herrmann, M. Fenstermacher, P. Ghendrih, M. Groth,<br />
A. Kirschner, S. Konoshima, B. LaBombard, P. Lang, A. W. Leonard,
P. Monier-Garbet, R. Neu, H. Pacher, B. Pegourie, R. A. Pitts,<br />
S. Takamura, J. Terry, E. Tsitrone and ITPA Scrape-off Layer<br />
and Divertor Physics Topical Group: Chapter 4: Power and<br />
particle control. Nuclear Fusion 47, S203-S263 (<strong>2007</strong>).<br />
Loarte, A., G. Saibene, R. Sartori, V. Riccardo, P. Andrew, J. Paley,<br />
W. Fundamenski, T. Eich, A. Herrmann, G. Pautasso, A. Kirk,<br />
G. Counsell, G. Federici, G. Strohmayer, D. Whyte, A. Leonard,<br />
R. A. Pitts, I. Landmann, B. Bazylev and S. Pestchanyi: Transient<br />
Heat Loads in Current Fusion Experiments, Extrapolation<br />
to ITER and Consequences for its Operation. Physica<br />
Scripta T128, 222-228 (<strong>2007</strong>).<br />
Lundwall, M., W. Pokapanich, H. Bergersen, A. Lindblad,<br />
T. Rander, G. Öhrwall, M. Tchaplyguine, S. Barth, U. Hergenhahn,<br />
S. Svensson and O. Björneholm: Self-assembled heterogeneous<br />
argon/neon core-shell clusters studied by photoelectron<br />
spectroscopy. Journal of Chemical Physics 126, 214706 (<strong>2007</strong>).<br />
Lunt, T., C. Silva, H. Fernandes, C. Hidalgo, M. A. Pedrosa,<br />
P. Duarte, H. Figueiredo and T. Pereira: Edge plasma pressure<br />
measurements using a mechanical force sensor on the<br />
tokamak ISTTOK. Plasma Physics and Controlled Fusion 49,<br />
1783-1790 (<strong>2007</strong>).<br />
Lyssoivan, A., R. Koch, D. Van Eester, G. Van Wassenhov,<br />
M. Vervier, R. Weynants, M. Freisinger, A. Kreter, V. Philipps,<br />
H. Reimer, U. Samm, G. Sergienko, V. Bobkov, H.-U. Fahrbach,<br />
D. Hartmann, A. Herrmann, J.-M. Noterdaeme, V. Rohde,<br />
W. Suttrop, E. Gauthier, E. de la Cal, TEXTOR Team and<br />
ASDEX Upgrade Team: New scenarios of ICRF wall conditioning<br />
in TEXTOR and ASDEX Upgrade. Journal of<br />
Nuclear Materials 363-365, 1358-1363 (<strong>2007</strong>).<br />
Maggi, C. F., R. J. Groebner, N. Oyama, R. Sartori, L. Horton,<br />
A. C. C. Sips, W. Suttrop, ASDEX Upgrade Team, A. Leonard,<br />
T. C. Luce, M. R. Wade, DIII-D Team, Y. Kamada, H. Urano,<br />
JT-60U Team, Y. Andrew, C. Giroud, E. Joffrin, E. de la Luna<br />
and EFDA JET Contributors for the Pedestal and Edge Physics<br />
and the Stead State Operation Topical Groups of the ITPA:<br />
Characteristics of H-mode pedestal in improved confinement<br />
scenarios in ASDEX Upgrade, DIII-D, JET and JT-60U.<br />
Nuclear Fusion 47, 535-551 (<strong>2007</strong>).<br />
Mahdizadeh, N., F. Greiner, T. Happel, A. Kendl, M. Ramisch,<br />
B. D. Scott and U. Stroth: Investigation of the parallel dynamics<br />
of drift-wave turbulence in toroidal plasmas. Plasma<br />
Physics and Controlled Fusion 49, 1005-1017 (<strong>2007</strong>).<br />
Maier, H., T. Hirai, M. Rubel, R. Neu, P. Mertens, H. Greuner,<br />
C. Hopf, G. Matthews, O. Neubauer, G. Piazza, E. Gauthier,<br />
J. Likonen, R. Mitteau, G. Maddaluno, B. Riccardi, V. Philipps,<br />
C. Ruset, C. Lungu and JET EFDA Contributors: Tungsten<br />
Publications<br />
129<br />
and Beryllium Armour Development for the JET ITER-like<br />
Wall Project. Nuclear Fusion 47, 222-227 (<strong>2007</strong>).<br />
Maier, H., R. Neu, H. Greuner, C. Hopf, G. Matthews, G. Piazza,<br />
T. Hirai, G. Counsell, X. Courtois, R. Mitteau, E. Gauthier,<br />
J. Likonen, G. Maddaluno, V. Philipps, B. Riccardi, C. Ruset and<br />
EFDA-JET Team: Tungsten Coatings for the JET ITER-like<br />
Wall Project. Journal of Nuclear Materials 363-365, 1246-<br />
1250 (<strong>2007</strong>).<br />
Manini, A., J. Berrino, S. Cirant, G. D’Antona, F. Gandini,<br />
G. Grünwald, F. Leuterer, M. Maraschek, F. Monaco, G. Neu,<br />
G. Raupp, D. Sormani, J. Stober, W. Suttrop, W. Treutterer,<br />
D. Wagner, H. Zohm and ASDEX Upgrade Team: Development<br />
of a feedback system to control MHD instabilities in ASDEX<br />
Upgrade. Fusion Engineering and Design 82, 995-1001 (<strong>2007</strong>).<br />
Maraschek, M., G. Gantenbein, Q. Yu, H. Zohm, S. Günter,<br />
F. Leuterer, A. Manini, ECHR Group and ASDEX Upgrade<br />
Team: Enhancement of the Stabilization Efficiency of a Neoclassical<br />
Magnetic Island by Modulated Electron Cyclotron<br />
Current Drive in the ASDEX Upgrade Tokamak. Physical<br />
Review Letters 98, 025005 (<strong>2007</strong>).<br />
Marcuzzi, D., P. Agostinetti, M. Dalla Palma, H. D. Falter,<br />
B. Heinemann and R. Riedl: Design of the RF ion source for the<br />
ITER NBI. Fusion Engineering and Design 82, 798-805 (<strong>2007</strong>).<br />
Marki, J., R. A. Pitts, T. Eich, A. Herrmann, J. Horacek,<br />
F. Sanchez and G. Veres: Sheath heat transmission factors on<br />
TCV. Journal of Nuclear Materials 363-365, 382-388 (<strong>2007</strong>).<br />
Markin, S. N., D. Primetzhofer, J. E. Valdes, E. Taglauer and<br />
P. Bauer: Neutralization of low energy He + ions by Cu in the<br />
auger regime. Nuclear Instruments and Methods in Physics<br />
Research B: Beam Interactions with Materials and Atoms 258,<br />
18-20 (<strong>2007</strong>).<br />
Marushchenko, N. B., V. Erckmann, H. J. Hartfuß, M. Hirsch,<br />
H. P. Laqua, H. Maaßberg and Y. Turkin: Ray Tracing Simulations<br />
of ECR Heating and ECE Diagnostic at W7-X Stellarator.<br />
Plasma and Fusion Research 2, S1129 (<strong>2007</strong>).<br />
Matthews, G., P. Edwards, T. Hirai, M. Kear, A. Lioure, P. Lomas,<br />
A. Loving, C. Lungu, H. Maier, P. Mertens, D. Neilson, J. Pamela,<br />
V. Philipps, G. Piazza, V. Riccardo, M. Rubel, C. Ruset, E. Villedieu,<br />
M. Way and ITER-Like Wall Project Team: Overview of the<br />
ITER-like Wall Project. Physica Scripta T128, 137-143 (<strong>2007</strong>).<br />
Matyash, K., R. Schneider, K. Dittmann, J. Meichsner, F. X. Bronold<br />
and D. Tskhakaya: Radio-frequency discharges in oxygen: III.<br />
Comparison of modelling and experiment. Journal of<br />
Physics D 40, 6601-6607 (<strong>2007</strong>).
Matyash, K., R. Schneider, F. Taccogna, A. Hattayama,<br />
S. Longo, M. Capitelli, D. Tskhakaya and F. X. Bronold:<br />
Particle in Cell Simulation of Low Temperature Laboratory<br />
Plasma. Contributions to Plasma Physics 47, 595-634 (<strong>2007</strong>).<br />
Matyash, K., R. Schneider, F. Taccogna and D. Tskhakaya:<br />
Finite size effect of dust charging in the magnetized edge plasma.<br />
Journal of Nuclear Materials 363-365, 458-461 (<strong>2007</strong>).<br />
Mayer, M., J. Likonen, J. P. Coad, H. Maier, M. Balden,<br />
S. Lindig, E. Vainonen-Ahlgren, V. Philipps and JET-EFDA<br />
Contributors: Tungsten erosion in the outer divertor of JET.<br />
Journal of Nuclear Materials 363-365, 101-106 (<strong>2007</strong>).<br />
Mayer, M., V. Rohde, G. Ramos, E. Vainonen-Ahlgren,<br />
J. Likonen, J. Chen and ASDEX Upgrade Team: Erosion of<br />
Tungsten and Carbon Markers in the Outer Divertor of<br />
ASDEX-Upgrade. Physica Scripta T128, 106-110 (<strong>2007</strong>).<br />
Mayer, M., V. Rohde, G. Ramos, E. Vainonen-Ahlgren,<br />
J. Likonen, A. Herrmann, R. Neu and ASDEX Upgrade Team:<br />
The Deuterium Inventory in ASDEX Upgrade. Nuclear<br />
Fusion 47, 1607-1617 (<strong>2007</strong>).<br />
McCormick, K., P. Grigull, H. Ehmler, E. Pasch, NBI Team,<br />
ECRH Team and W7-AS Team: A new edge-based energy<br />
scaling law for W7-AS and its implications for boundaryisland<br />
divertor operation. Journal of Nuclear Materials 363-365,<br />
389-394 (<strong>2007</strong>).<br />
McDonald, D. C., J. G. Cordey, K. Thomsen, O. J. W. F. Kardaun,<br />
J. A. Snipes, M. Greenwald, L. Sugiyama, F. Ryter, A. Kus,<br />
J. Stober, J. C. DeBoo, C. C. Petty, G. Bracco, M. Romanelli,<br />
Z. Cui, Y. Liu, Y. Miura, K. Shinohara, K. Tsuzuki, Y. Kamada,<br />
T. Takizuka, H. Urano, M. Valovic, R. Akers, C. Brickley, A. Sykes,<br />
M. J. Walsh, S. M. Kaye, C. Bush, D. Hogewei, Y. R. Martin,<br />
A. Cote, G. Pacher, J. Ongena, F. Imbeaux, G. T. Hoang,<br />
S. Lebedev, A. Chudnovskiy and V. Leonov: Recent progress<br />
on the development and analysis of the ITPA global H-mode<br />
confinement database. Nuclear Fusion 47, 147-174 (<strong>2007</strong>).<br />
Menmuir, S., E. Rachlew, U. Fantz, R. Pugno, R. Dux and<br />
ASDEX Upgrade Team: Molecular contribution to the Dα emission<br />
in the divertor of the ASDEX Upgrade experiment. Journal<br />
of Quantitative Spectroscopy and Radiative Transfer 105,<br />
425-437 (<strong>2007</strong>).<br />
Meyer-Spasche, R.: On difference schemes for quasilinear<br />
evolution problems. Electronic Transactions on Numerical<br />
Analysis 27, 78-93 (<strong>2007</strong>).<br />
Mikkelsen, D. R., H. Maaßberg, M. C. Zarnstorff, C. D. Beidler,<br />
W. A. Houlberg, W. Kernbichler, H. Mynick, D. A. Spong,<br />
Publications<br />
130<br />
P. Strand and V. Tribaldos: Assessment of Transport in<br />
NCSX. Fusion Science and Technology 51, 166-180 (<strong>2007</strong>).<br />
Milch, I.: Sonnenfeuer im Labor. Wo steht die Fusionsforschung?<br />
Kultur und Technik – das Magazin aus dem<br />
Deutschen Museum 31, 2, 46-51 (<strong>2007</strong>).<br />
Mishchenko, A., P. Helander and Y. Turkin: Curvature Particle<br />
Pinch in Tokamak and Stellarator Geometry. Physics of<br />
Plasmas 14, 102308 (<strong>2007</strong>).<br />
Mishchenko, A. and A. Könies: A many-particle approach to<br />
the gyro-kinetic theory. Journal of Plasma Physics 73, 757-772<br />
(<strong>2007</strong>).<br />
Missirlian, M., A. Durocher, A. Grosman, J. Schlosser, J. Boscary,<br />
F. Escourbiac and F. Cismondi: Qualification of high heat<br />
flux components: application to target elements of W7-X<br />
divertor. Physica Scripta T128, 182-188 (<strong>2007</strong>).<br />
Missirlian, M., H. Traxler, J. Boscary, A. Durocher, F. Escourbiac,<br />
J. Schlosser, B. Schedler and P. Schuler: Infrared thermography<br />
inspection methods applied to the target elements of W7-X<br />
divertor. Fusion Engineering and Design 82, 1747-1755 (<strong>2007</strong>).<br />
Mitteau, R., J. M. Missiaen, P. Brustolin, O. Ozer, A. Durocher,<br />
C. Ruset, C. P. Lungu, X. Courtois, C. Dominicy, H. Maier,<br />
C. Grisolia, G. Piazza and P. Chappuis: Recent developments<br />
toward the use of tungsten as armour material in plasma<br />
facing components. Fusion Engineering and Design 82,<br />
1700-1705 (<strong>2007</strong>).<br />
Mueck, A., Y. Camenen, S. Coda, L. Curchod, T. P. Goodman,<br />
H. P. Laqua, A. Pochelon, L. Porte, V. S. Udintsev, F. Volpe<br />
and TCV Team: Electron Bernstein Wave Heating and Emission<br />
in the TCV Tokamak. Fusion Science and Technology 52,<br />
221-229 (<strong>2007</strong>).<br />
Mueck, A., L. Curchod, Y. Camenen, S. Coda, T. P. Goodman,<br />
H. P. Laqua, A. Pochelon, L. Porte and F. Volpe: Demonstration<br />
of Electron-Bernstein-Wave Heating in a Tokamak<br />
via O-X-B Double-Mode Conversion. Physical Review<br />
Letters 98, 175004 (<strong>2007</strong>).<br />
Müller, H. W., V. Bobkov, A. Herrmann, M. Maraschek,<br />
J. Neuhauser, V. Rohde, A. Schmid, M. Tsalas and ASDEX<br />
Upgrade Team: Deuterium plasma flow in the scrape-off-layer<br />
of ASDEX Upgrade. Journal of Nuclear Materials 363-365,<br />
605-610 (<strong>2007</strong>).<br />
Müller, W.-C. and A. Busse: Diffusion and dispersion of passive<br />
tracers: Navier-Stokes vs. MHD turbulence. Europhysics<br />
Letters 78, 14003 (<strong>2007</strong>).
Müller, W.-C. and M. Thiele: Scaling and energy transfer in<br />
rotating turbulence. Europhysics Letters 77, 34003 (<strong>2007</strong>).<br />
Mukhovatov, V., M. Shimada, K. Lackner, D. J. Campbell,<br />
N. A. Uckan, J. C. Wesley, T. C. Hender, B. Lipschultz, A. Loarte,<br />
R. D. Stambaugh, R. J. Goldston, Y. Shimomura, M. Fujiwara,<br />
M. Nagami, V. D. Pustovitov, H. Zohm, ITPA CC Members,<br />
ITPA Topical Group Chairs and Co-Chairs and ITER International<br />
Team: Chapter 9: ITER contributions for Demo<br />
plasma development. Nuclear Fusion 47, S404-S413 (<strong>2007</strong>).<br />
Murakami, S., H. Yamada, A. Wakasa, H. Inagaki, K. Tanaka,<br />
K. Narihara, S. Kubo, T. Shimozuma, H. Funaba, J. Miyazawa,<br />
S. Morita, K. Ida, K. Y. Watanabe, M. Yokoyama, H. Maaßberg,<br />
C. D. Beidler and LHD Experimental Group: Effect of Neoclassical<br />
Transport Optimization on Electron Heat Transport<br />
in the Low-collisionality LHD Plasma. Fusion Science and<br />
Technology 51, 112-121 (<strong>2007</strong>).<br />
Murari, A., T. Edlington, J. Brzozowski, E. de la Luna, P. Andrew,<br />
G. Arnoux, F. E. Cecil, L. Cupido, D. Darrow, V. Kiptily,<br />
J. Fessey, E. Gauthier, S. Hacquin, K. Hill, A. Huber, T. Loarer,<br />
K. McCormick, M. Reich and JET-EFDA Contributors: JET<br />
new diagnostic capability on the route to ITER. Fusion<br />
Engineering and Design 82, 1161-1166 (<strong>2007</strong>).<br />
Nakamura, K., H. Iguchi, J. Schweinzer, A. Shimizu, M. Isobe,<br />
D. Takahashi, S. Nishimura, C. Suzuki, Y. Yoshimura, K. Nagaoka,<br />
T. Minami, T. Akiyama, K. Ida, K. Matsuoka and S. Okamura:<br />
Two-dimensional plasma structure in the edge region of the<br />
compact helical system. Nuclear Fusion 47, 251-256 (<strong>2007</strong>).<br />
Neu, G., K. Engelhardt, G. Raupp, W. Treutterer, D. Zasche,<br />
T. Zehetbauer and ASDEX Upgrade Team: The ASDEX<br />
Upgrade Discharge Schedule. Fusion Engineering and<br />
Design 82, 1111-1116 (<strong>2007</strong>).<br />
Neu, R., M. Balden, V. Bobkov, R. Dux, O. Gruber, A. Herrmann,<br />
A. Kallenbach, M. Kaufmann, C. F. Maggi, H. Maier, H. W. Müller,<br />
T. Pütterich, R. Pugno, V. Rohde, A. C. C. Sips, J. Stober,<br />
W. Suttrop, C. Angioni, C. V. Atanasiu, W. Becker, K. Behler,<br />
K. Behringer, A. Bergmann, T. Bertoncelli, R. Bilato, A. Bottino,<br />
M. Brambilla, F. Braun, A. Buhler, A. Chankin, G. Conway,<br />
D. P. Coster, P. de Marne, S. Dietrich, K. Dimova, R. Drube,<br />
T. Eich, K. Engelhardt, H.-U. Fahrbach, U. Fantz, L. Fattorini,<br />
J. Fink, R. Fischer, A. Flaws, P. Franzen, J. C. Fuchs, K. Gal,<br />
M. Garcia Munoz, M. Gemisic-Adamov, L. Giannone, S. Gori,<br />
S. da Graca, H. Greuner, A. Gude, S. Günter, G. Haas,<br />
J. Harhausen, B. Heinemann, N. Hicks, J. Hobirk, D. Holtum,<br />
C. Hopf, L. Horton, M. Huart, V. Igochine, S. Kalvin, O. Kardaun,<br />
M. Kick, G. Kocsis, H. Kollotzek, C. Konz, K. Krieger,<br />
T. Kurki-Suonio, B. Kurzan, K. Lackner, P. T. Lang, P. Lauber,<br />
M. Laux, J. Likonen, L. Liu, A. Lohs, K. Mank, A. Manini,<br />
Publications<br />
131<br />
M.-E. Manso, M. Maraschek, P. Martin, Y. Martin, M. Mayer,<br />
P. McCarthy, K. McCormick, H. Meister, F. Meo, P. Merkel,<br />
R. Merkel, V. Mertens, F. Merz, H. Meyer, M. Mlyneck,<br />
F. Monaco, H. Murmann, G. Neu, J. Neuhauser, B. Nold,<br />
J.-M. Noterdaeme, G. Pautasso, G. Pereverzev, E. Poli,<br />
M. Püschel, G. Raupp, M. Reich, B. Reiter, T. Ribeiro, R. Riedl,<br />
J. Roth, M. Rott, F. Ryter, W. Sandmann, J. Santos, K. Sassenberg,<br />
A. Scarabosio, G. Schall, J. Schirmer, A. Schmid, W. Schneider,<br />
G. Schramm, R. Schrittwieser, W. Schustereder, J. Schweinzer,<br />
S. Schweizer, B. Scott, U. Seidel, F. Serra, M. Sertoli, A. Sigalov,<br />
A. Silva, E. Speth, A. Stäbler, K.-H. Steuer, E. Strumberger,<br />
G. Tardini, C. Tichmann, W. Treutterer, C. Tröster, L. Urso,<br />
E. Vainonen-Ahlgren, P. Varela, L. Vermare, D. Wagner,<br />
M. Wischmeier, E. Wolfrum, E. Würsching, D. Yadikin, Q. Yu,<br />
D. Zasche, T. Zehetbauer, M. Zilker and H. Zohm: Plasma<br />
wall interaction and its implication in an all tungsten divertor<br />
tokamak. Invited Paper. Plasma Physics and Controlled<br />
Fusion 49, B59-B70 (<strong>2007</strong>).<br />
Neu, R., V. Bobkov, R. Dux, A. Kallenbach, T. Pütterich,<br />
H. Greuner, O. Gruber, A. Herrmann, C. Hopf, K. Krieger,<br />
C. F. Maggi, H. Maier, M. Mayer, V. Rohde, K. Schmid, W. Suttrop<br />
and ASDEX Upgrade Team: Final steps to an all tungsten<br />
divertor tokamak. Journal of Nuclear Materials 363-365, 52-59<br />
(<strong>2007</strong>).<br />
Neu, R., H. Maier, E. Gauthier, H. Greuner, T. Hirai, C. Hopf,<br />
J. Likonen, G. Maddaluno, F. Matthews, R. Mitteau, V. Philipps,<br />
G. Piazza, C. Ruset and JET EFDA Contributors: Investigation<br />
of Tungsten Coatings on Graphite and CFC. Physica<br />
Scripta T128, 150-156 (<strong>2007</strong>).<br />
Neu, R., T. Pütterich, R. Dux, A. Pospieszczyk, A. Sergienko<br />
and ASDEX Upgrade Team: Tungsten Spectroscopy for Fusion<br />
Plasmas. Atomic and Molecular Data and their Applications:<br />
5 th International Conference on Atomic and Molecular<br />
Data and Their Applications (ICAMDATA). (Ed.) E. Roueff.<br />
AIP Conference Proceedings 901. American <strong>Institut</strong>e of<br />
Physics, Melville, NY, 85-94 (<strong>2007</strong>).<br />
Nevins, W. M., S. E. Parker, Y. Chen, J. Candy, A. Dimits,<br />
W. Dorland, G. W. Hammett and F. Jenko: Verification of<br />
gyrokinetic δf simulations of electron temperature gradient<br />
turbulence. Physics of Plasmas 14, 062301 (<strong>2007</strong>).<br />
Newton, S. L., P. Helander and P. J. Catto: Collisional bulk<br />
ion transport and poloidal rotation driven by neutral beam<br />
injection. Physics of Plasmas 14, 062301 (<strong>2007</strong>).<br />
Nieckchen, P. and P. Batistoni: Imbrigliare l’energia delle<br />
stelle. ENEA – Dipartimento Fusione, Tecnologie e Presdio<br />
Nucleari Associazione EURATOM-ENEA, Frascati, 20 p.<br />
(<strong>2007</strong>).
Nieckchen, P. and P. Batistoni: Sulla strada della fusione –<br />
Opportunità per l’industria italiana. ENEA – Dipartimento Fusione,<br />
Tecnologie e Presdio Nucleari Associazione EURATOM-<br />
ENEA, Frascati, 16 p. (<strong>2007</strong>).<br />
Omar, B., A. Wierling, S. Günter and G. Röpke: Hydrogen<br />
Balmer Spectrum from a High-Pressure Arc Discharge:<br />
Revisited. Contributions to Plasma Physics 47, 315-323<br />
(<strong>2007</strong>).<br />
Orsitto, F. P., J. M. Noterdaeme, A. E. Costley, A. J. H. Donné<br />
and ITPA TG on Diagnostics: Requirements for fast particle<br />
measurements on ITER and candidate measurement techniques.<br />
Nuclear Fusion 47, 1311-1317 (<strong>2007</strong>).<br />
Osiac, M., T. Schwarz-Selinger, D. O’Connell, B. Heil, Z. L. Petrovic,<br />
M. M. Turner, T. Gans and U. Czarnetzki: Plasma Boundary<br />
Sheath in the Afterglow of a Pulsed Inductively Coupled RF<br />
Plasma. Plasma Sources Science Technology 16, 355-363<br />
(<strong>2007</strong>).<br />
Pacher, H. D., A. S. Kukushkin, G. W. Pacher, G. Janeschitz,<br />
D. Coster, V. Kotov and D. Reiter: Effect of the tokamak size<br />
in edge transport modelling and implications for DEMO.<br />
Journal of Nuclear Materials 363-365, 400-406 (<strong>2007</strong>).<br />
Padberg, K., T. Hauff, F. Jenko and O. Junge: Lagrangian<br />
structures and transport in turbulent magnetized plasmas.<br />
New Journal of Physics 9, 400 (<strong>2007</strong>).<br />
http://www.iop.org/EJ/abstract/1367-2630/9/11/400<br />
Pan, Y. D. and R. Schneider: Study of the specific detachment<br />
characteristics of HL-2A. Journal of Nuclear Materials<br />
363-365, 407-411 (<strong>2007</strong>).<br />
Peeters, A. G., C. Angioni, A. C. C. Sips and ASDEX Upgrade<br />
Team: On the extrapolation to ITER of discharges in present<br />
tokamaks. Nuclear Fusion 47, 1341-1345 (<strong>2007</strong>).<br />
Peeters, A. G., C. Angioni and D. Strintzi: Toroidal Momentum<br />
Pinch Velocity due to the Coriolis Drift Effect on Small<br />
Scale Instabiltities in a Toroidal Plasma. Physical Review<br />
Letters 98, 265003 (<strong>2007</strong>).<br />
Pautasso, G., C. J. Fuchs, O. Gruber, C.F. Maggi, M. Maraschek,<br />
T. Pütterich, V. Rohde, C. Wittmann, E. Wolfrum, P. Cierpka,<br />
M. Beck and ASDEX Upgrade Team: Plasma shut-down with<br />
fast impurity puff on ASDEX Upgrade. Nuclear Fusion 47,<br />
900-913 (<strong>2007</strong>).<br />
Perfilov, S., A. Melnikov, L. Krupnik and H.-J. Hartfuß:<br />
Applicability of heavy-ion-beam probing for stellarator W7-X.<br />
Fusion Science and Technology 51, 38-45 (<strong>2007</strong>).<br />
Publications<br />
132<br />
Piazza, G., G. F. Matthews, J. Pamela, H. Altmann, J. P. Coad,<br />
T. Hirai, A. Lioure, H. Maier, Ph. Mertens, V. Philipps,<br />
V. Riccardo, M. Rubel, E. Villedieu and Collaborators of the<br />
JET ITER-like Project: R&D on tungsten plasma facing<br />
components for the JET ITER-like wall project. Journal of<br />
Nuclear Materials 367-370, 1438-1443 (<strong>2007</strong>).<br />
Pitts, R. A., P. Andrew, G. Arnoux, T. Eich, W. Fundamenski,<br />
A. Huber, C. Silva, D. Tskhakaya and JET EFDA Contributors:<br />
ELM Transport in the JET Scrape-off Layer. Nuclear Fusion 47,<br />
1437-1448 (<strong>2007</strong>).<br />
Pitts, R. A., J. Horacek, W. Fundamenski, O. E. Garcia,<br />
A. H. Nielsen, M. Wischmeier, V. Naulin and J. Juul Rasmussen:<br />
Parallel SOL flow on TCV. Journal of Nuclear Materials<br />
363-365, 505-510 (<strong>2007</strong>).<br />
Plankensteiner, A., A. Leuprecht, B. Schedler, K. H. Scheiber<br />
and H. Greuner: Finite element based design optimization<br />
of Wendelstein 7-X divertor components under high heat<br />
flux loading. Fusion Engineering and Design 82, 1813-1819<br />
(<strong>2007</strong>).<br />
Pochelon, A., A. Mueck, L. Curchod, Y. Camenen, S. Coda,<br />
B. P. Duval, T. P. Goodman, I. Klimanov, H. P. Laqua,<br />
Y. Martin, J.-M. Moret, L. Porte, A. Sushkov, V. S. Udintsev,<br />
F. Volpe and TCV Team: Electron Bernstein wave heating of<br />
over-dense H-mode plasmas in the TCV tokamak via O-X-B<br />
double mode conversion. Nuclear Fusion 47, 1552-1558 (<strong>2007</strong>).<br />
Podoba, Y. Y., H. P. Laqua, G. B. Warr, M. Schubert, M. Otte,<br />
S. Marsen, F. Wagner and E. Holzhauer: Direct Observation<br />
of Electron Bernstein Wave Heating by OXB Mode conversion<br />
at low magnetic field in the WEGA Stellarator. Physical<br />
Review Letters 98, 255003 (<strong>2007</strong>).<br />
Pokol, G., G. Por, S. Zoletnik and W7-AS Team: Application of<br />
a bandpower correlation method to the statistical analysis of<br />
MHD bursts in quiescent Wendelstein-7 AS stellarator plasmas.<br />
Plasma Physics and Controlled Fusion 49, 1391-1408 (<strong>2007</strong>).<br />
Poulipoulis, G., G. N. Throumoulopoulos and H. Tasso: Twofluid<br />
tokamak equilibria with reversed magnetic shear and<br />
sheared flow. Journal of Plasma Physics 73, 347-366 (<strong>2007</strong>).<br />
Primetzhofer, D., S. N. Markin, R. Kolarova, M. Draxler,<br />
R. Beikler, E. Taglauer and P. Bauer: On the Surface Sensitivity<br />
of Angular Scans in LEIS. Nuclear Instruments and<br />
Methods in Physics Research B: Beam Interactions with<br />
Materials and Atoms 258, 36-39 (<strong>2007</strong>).<br />
Pugno, R., M. J. Baldwin, R. P. Doerner, J. Hanna, D. Nishijima<br />
and G. Antar: Surface effects on graphite samples exposed
to beryllium-seeded plasmas under transient power load on<br />
PISCES-B. Journal of Nuclear Materials 363-365, 1277-1282<br />
(<strong>2007</strong>).<br />
Radtke, R., C. Biedermann, P. Mandelbaum and J. L. Schwob:<br />
X ray and EUV spectroscopic measurements of highly charged<br />
tungsten ions relevant to fusion plasmas. Journal of Physics.<br />
Conference Series 58, 113-116 (<strong>2007</strong>).<br />
Rai, A., P. N. Maya, R. Schneider, S. P. Deshpande and M. Warrier:<br />
Dynamic Monte-Carlo modeling of hydrogen isotope diffusion<br />
in co-deposited layers. Journal of Nuclear Materials 363-365,<br />
1272-1276 (<strong>2007</strong>).<br />
Ramponi, G., D. Farina, M. A. Henderson, E. Poli, G. Saibene<br />
and H. Zohm: ITER ECRH-ECCD System Capabilities for<br />
Extended Physics Applications. Fusion Science and Technology<br />
52, 193-201 (<strong>2007</strong>).<br />
Raupp, G., W. Treutterer, V. Mertens, G. Neu, A. Sips, D. Zasche,<br />
T. Zehetbauer and ASDEX Upgrade Team: Control processes<br />
and machine protection on ASDEX Upgrade. Fusion Engineering<br />
and Design 82, 1102-1110 (<strong>2007</strong>).<br />
Reich, J., A. Cardella, A. Capriccioli, T. Koppe, B. Missal,<br />
W. Löhrer, S. Langone and P.-C. Sassone: Experimental verification<br />
of the axial and lateral stiffness of large W7-X rectangular<br />
bellows. Fusion Engineering and Design 82, 1924-1928 (<strong>2007</strong>).<br />
Reiman, A. A., M. C. Zarnstorff, D. Monticello, A. Weller,<br />
J. Geiger and W7-AS Team: Pressure-induced, breaking of<br />
equilibrium flux surfaces in the W7AS stellarator. Nuclear<br />
Fusion 47, 572-578 (<strong>2007</strong>).<br />
Reinelt, M. and C. Linsmeier: Enhanced room temperature<br />
erosion of ultra-thin carbon films on beryllium, titanium and<br />
tantalum by deuterium ions. Nuclear Instruments and Methods<br />
in Physics Research B: Beam Interactions with Materials<br />
and Atoms 258, 270-273 (<strong>2007</strong>).<br />
Reinelt, M. and C. Linsmeier: Temperature programmed<br />
desorption of 1 keV deuterium implanted into clean beryllium.<br />
Physica Scripta T128, 111-114 (<strong>2007</strong>).<br />
Rohde, V., R. Dux, A. Kallenbach, K. Krieger, R. Neu and<br />
ASDEX Upgrade Team: Wall conditioning in ASDEX Upgrade.<br />
Journal of Nuclear Materials 363-365, 1369-1374 (<strong>2007</strong>).<br />
Roth, J., V. K. Alimov, A. Golubeva, R. Doerner, J. Hanna,<br />
E. Tsitrone, C. Brosset, V. Rohde, A. Herrmann and M. Mayer:<br />
Deuterium retention in carbon fibre composites NB31 and<br />
N11 irradiated with low-energy D ions. Journal of Nuclear<br />
Materials 363-365, 822-826 (<strong>2007</strong>).<br />
Publications<br />
133<br />
Roth, J., E. Tsitrone and A. Loarte: Plasma-Wall-Interaction:<br />
Important Ion Induced Surface Processes and Strategy of the<br />
EU Task Force. Nuclear Instruments and Methods in Physics<br />
Research B: Beam Interactions with Materials and Atoms 258,<br />
253-363 (<strong>2007</strong>).<br />
Rozhansky, V., P. Molchanov, S. Voskoboynikov, G. Counsell,<br />
D. Coster and R. Schneider: Modeling of the parametric<br />
dependence of the edge toroidal rotation for MAST and<br />
ASDEX Upgrade. Journal of Nuclear Materials 363-365,<br />
664-668 (<strong>2007</strong>).<br />
Rudakov, D. L., W. Jacob, K. Krieger, A. Litnovsky, V. Philipps,<br />
W. P. West, C. P. C. Wong, S. L. Allen, R. J. Bastasz, J. A. Boedo,<br />
N. H. Brooks, R. L. Boivin, G. De Temmerman, M. E. Fenstermacher,<br />
M. Groth, E. M. Hollmann, C. J. Lasnier, A. G. McLean,<br />
R. A. Moyer, P. C. Stangeby, W. R. Wampler, J. G. Watkins,<br />
P. Wienhold and J. Whaley: DiMES studies of temperature<br />
dependence of carbon erosion and re-deposition in DIII-D<br />
divertor. Physica Scripta T128, 29-34 (<strong>2007</strong>).<br />
Rummel, K., M. Czerwinski, F. Hurd, A. John, H. Lentz, G. Czymek,<br />
B. Giesen, F. Harberts, S. A. Egorov, V. E. Korsunsky, I. Y. Rodin,<br />
P. Bruzzone, B. Stepanov and M. Vogel: Test results from the<br />
full size prototype test of W7-X joint. Fusion Engineering<br />
and Design 82, 1526-1531 (<strong>2007</strong>).<br />
Ruset, C., E. Grigore, H. Maier, R. Neu, X. Li, H. Dong,<br />
R. Mitteau and X. Courtois: W coatings deposited on CFC<br />
tiles by Combined Magnetron Sputtering and Ion Implantation<br />
technique. Physica Scripta T128, 171-174 (<strong>2007</strong>).<br />
Sadykova, S. and W. Ebeling: Electric Microfield Distributions<br />
in Dense One- and Two-Component Plasmas. Contributions<br />
to Plasma Physics 47, 659-669 (<strong>2007</strong>).<br />
Saibene, G., N. Oyama, J. Lönroth, Y. Andrew, E. de la Luna,<br />
C. Giroud, G. T. A. Huysmans, Y. Kamada, M. A .H. Kempenaars,<br />
A. Loarte, D. McDonald, M. M. F Nave, A. Meiggs, V. Parail,<br />
R. Sartori, S. Sharapov, J. Stober, T. Suzuki, M. Takechi, K. Toi<br />
and H. Urano: The H-mode pedestal, ELMs and TF ripple<br />
effects in JT-60U/JET dimensionless identitity experiments.<br />
Nuclear Fusion 47, 969-983 (<strong>2007</strong>).<br />
Salancon, E., T. Dürbeck, T. Schwarz-Selinger and W. Jacob:<br />
Reactivity of soft amorphous hydrogenated carbon films in<br />
ambient atmosphere. Journal of Nuclear Materials 363-365,<br />
944-948 (<strong>2007</strong>).<br />
Sardei, F., Y. Feng, J. Kißlinger, P. Grigull, M. Kobayashi,<br />
D. Harting, D. Reiter, G. Federici and A. Loarte: Non-axisymmetric<br />
SOL-transport study for tokamaks and stellarators.<br />
Journal of Nuclear Materials 363-365, 511-516 (<strong>2007</strong>).
Sborchia, C.: The Manufacture of the W7-X Superconducting<br />
Magnet System as Relevant Experience for the Construction<br />
of the Next Fusion Devices. IEEE Transactions on Applied<br />
Superconductivity 17, 1334-1337 (<strong>2007</strong>).<br />
Scarabosio, A., A. Pochelon and Y. Martin: Plasma shape<br />
stabilization of current rise MHD instabilities in TCV. Plasma<br />
Physics and Controlled Fusion 49, 1019-1039 (<strong>2007</strong>).<br />
Schacht, J., H. Laqua, M. Lewerentz, I. Müller, S. Pingel,<br />
A. Spring and A. Wölk: Overview and status of the control<br />
system of Wendelstein 7-X. Fusion Engineering and Design 82,<br />
988-994 (<strong>2007</strong>).<br />
Schauer, F. and W7-X Team: Status of Wendelstein 7-X Construction.<br />
Fusion Engineering and Design 82, 443-453 (<strong>2007</strong>).<br />
Schirmer, J., G. D. Conway, E. Holzhauer, W. Suttrop, H. Zohm<br />
and ASDEX Upgrade Team: Radial correlation length measurements<br />
on ASDEX Upgrade using correlation Doppler<br />
reflectometry. Plasma Physics and Controlled Fusion 49,<br />
1019-1039 (<strong>2007</strong>).<br />
Schlosser, J., E. Martin, C. Henninger, J. Boscary, G. Camus,<br />
F. Escourbiac, D. Leguillon, M. Missirlian and R. Mitteau:<br />
CFC/Cu bond damage in actively cooled plasma facing<br />
components. Physica Scripta T128, 204-208 (<strong>2007</strong>).<br />
Schmid, K., M. J. Baldwin, R. P. Doerner and D. Nishijima:<br />
Beryllium layer deposition on carbon and tungsten from beryllium-seeded<br />
plasmas. Nuclear Technology 159, 238-244 (<strong>2007</strong>).<br />
Schmid, A., A. Herrmann, V. Rohde, M. Maraschek, H. W. Müller<br />
and ASDEX Upgrade Team: Magnetically driven filament<br />
probe. Review of Scientific Instruments 78, 053502 (<strong>2007</strong>).<br />
Schmid, M., S. Illya, G. Dammertz, V. Erckmann and M. Thumm:<br />
Transverse field collector sweep system for high power CW<br />
gyrotrons. Fusion Engineering and Design 82, 744-750 (<strong>2007</strong>).<br />
Schmid, K., K. Krieger, A. Kukushkin and A. Loarte:<br />
DIVIMP modelling of tungsten impurity transport in ITER.<br />
Journal of Nuclear Materials 363-365, 674-679 (<strong>2007</strong>).<br />
Schmid, K., T. Schwarz-Selinger, W. Jacob, R. Dux and<br />
ASDEX-Upgrade Team: The implications of high-Z first<br />
wall materials on noble gas wall recycling. Nuclear Fusion 47,<br />
984-989 (<strong>2007</strong>).<br />
Schneider, R., A. Rai, A. Mutzke, M. Warrier, E. Salonen and<br />
K. Nordlund: Dynamic Monte-Carlo modeling of hydrogen<br />
isotope reactive-diffusive transport in porous graphite.<br />
Journal of Nuclear Materials 367-370, 1238-1242 (<strong>2007</strong>).<br />
Publications<br />
134<br />
Schneider, R. and A. Runov: Challenges in plasma edge fluid<br />
modelling. Plasma Physics and Controlled Fusion 49, S87-S95<br />
(<strong>2007</strong>).<br />
Schröder, M., J. Holluba and K. Heyn: Quality assurance of<br />
aluminium weld seams and cast casings of the W7-X coils.<br />
Fusion Engineering and Design 82, 1532-1537 (<strong>2007</strong>).<br />
Schubert, T., A. Brendel, K. Schmid, T. Koeck, L. Ciupinski,<br />
W. Zielinski, T. Weißgärber and B. Kieback: Interfacial design<br />
of Cu/SiC composites prepared by Powder Metallurgy for<br />
Heat sink applications. Composites Part A: Applied Science<br />
and Manufacturing 38, 2398-2403 (<strong>2007</strong>).<br />
Schubert, M., M. Endler, H. Thomsen and W7-AS Team:<br />
Spatio-temporal temperature fluctuation measurements by<br />
means of a fast swept Langmuir probe array. Review of<br />
Scientific Instruments 78, 053505 (<strong>2007</strong>).<br />
Schustereder, W., A. Herrmann, V. Rohde and ASDEX Upgrade<br />
Team: Impurity survey after Boronization in ASDEX Upgrade<br />
measured by a collector probe. Physica Scripta T128, 14-17<br />
(<strong>2007</strong>).<br />
Schustereder, W., K. Krieger, A. Herrmann, V. Rohde and<br />
ASDEX Upgrade Team: Discharge resolved impurity flux<br />
measurements in the edge plasma of ASDEX Upgrade by<br />
exposure of collector probes. Journal of Nuclear Materials<br />
363-365, 242-246 (<strong>2007</strong>).<br />
Schustereder, W., B. Rasul, N. Endstrasser, V. Grill, P. Scheier<br />
and T. Märk: Sticking Coefficient and SIMS of Hydrocarbons<br />
on Fusion Relevant Plasma-Sprayed Tungsten Surfaces.<br />
Nuclear Instruments and Methods in Physics Research B:<br />
Beam Interactions with Materials and Atoms 258, 278-281<br />
(<strong>2007</strong>).<br />
Schwarz-Selinger, T., C. Hopf, C. Sun and W. Jacob: Growth<br />
and erosion of amorphous carbon (a-C:H) films by low-temperature<br />
laboratory plasmas containing H and N mixtures.<br />
Journal of Nuclear Materials 363-365, 174-178 (<strong>2007</strong>).<br />
Scott, B. D.: Nonlinear polarization and dissipative correspondence<br />
between low-frequency fluid and gyrofluid equations.<br />
Physics of Plasmas 14, 102318 (<strong>2007</strong>).<br />
Scott, B. D.: Tokamak edge turbulence: background theory<br />
and computation. Plasma Physics and Controlled Fusion 49,<br />
S25-S41 (<strong>2007</strong>).<br />
Scott, S., A. Bader, M. Bakhtiari, N. Basse, W. Beck, T. Biewer,<br />
S. Bernabei, P. Bonoli, B. Bose, R. Bravenec, I. Bespamyatnov,<br />
R. Childs, I. Cziegler, R. Doerner, E. Edlund, D. Ernst, A. Fasoli,
M. Ferrara, C. Fiore, T. Fredian, A. Graf, T. Graves, R. Granetz,<br />
N. Greenough, M. Greenwald, M. Grimes, O. Grulke, D. Gwinn,<br />
R. Harvey, S. Harrison, T. C. Hender, J. Hosea, D. F. Howell,<br />
A. E. Hubbard, J. W. Hughes, I. Hutchinson, A. Ince-Cushman,<br />
J. Irby, T. Jernigan, D. Johnson, J. Ko, P. Koert, B. LaBombard,<br />
A. Kanojia, L. Lin, Y. Lin, B. Lipschultz, J. Liptac, A. Lynn,<br />
P. MacGibbon, E. Marmar, K. Marr, M. May, D. R. Mikkelsen,<br />
R. McDermott, A. Parisot, R. Parker, C. K. Phillips, P. Phillips,<br />
M. Porkolab, M. Reinke, J. Rice, W. Rowan, M. Sampsell,<br />
G. Schilling, A. Schmidt, N. Smick, A. Smirnov, J. Snipes, D. Stotler,<br />
J. Stillerman, V. Tang, D. Terry, J. Terry, M. Ulrickson, R. Vieira,<br />
G. Wallace, D. Whyte, J. R. Wilson, G. Wright, J. Wright, S. Wolfe,<br />
S. Wukitch, G. Wurden, H. Yuh, K. Zhurovich, J. Zaks and<br />
S. Zweben: Overview of the Alcator C-MOD research programme.<br />
Nuclear Fusion 47, S598-S607 (<strong>2007</strong>).<br />
Sengupta, A., J. Geiger and P. J. Mc Carthy: Statistical<br />
Analysis of the equilibrium configurations of W7-X stellarator.<br />
Plasma Physics and Controlled Fusion 49, 649-673 (<strong>2007</strong>).<br />
Sharma, A., R. Schneider, U. von Toussaint and K. Nordlund:<br />
Hydrocarbon radicals interaction with amorphous carbon surfaces.<br />
Journal of Nuclear Materials 363-365, 1283-1288 (<strong>2007</strong>).<br />
Shimada, M., D. J. Campbell, V. Mukhovatov, M. Fujiwara,<br />
N. Kirneva, K. Lackner, M. Nagami, V. D. Pustovitov, N. Uckan,<br />
J. Wesley, N. Asakura, A. E. Costley, A. J. H. Donne, E. J. Doyle,<br />
A. Fasoli, C. Gormezano, Y. Gribov, O. Gruber, T. C. Hender,<br />
W. Houlberg, S. Ide, Y. Kamada, A. Leonard, B. Lipschultz,<br />
A. Loarte, K. Miyamoto, V. Mukhovatov, T. H. Osborne, A. Polevoi<br />
and A. C. C. Sips: Chapter 1: Overview and summary. Nuclear<br />
Fusion 47, S1-S17 (<strong>2007</strong>).<br />
Shimizu, S., T. Shimizu, B. M. Annaratone, W. Jacob, C. Linsmeier,<br />
S. Lindig, R. W. Stark, F. Jamitzky, H. Thomas, N. Sato and<br />
G. E. Morfill: The approach to diamond growth on the levitated<br />
seed particles. Applied Surface Science 254, 177-180 (<strong>2007</strong>).<br />
Sips, A. C. C., G. Tardini, C. B. Forest, O. Gruber, P. J. McCarthy,<br />
A. Gude, L. D. Horton, V. Igochine, O. Kardaun, C. F. Maggi,<br />
M. Maraschek, V. Mertens, R. Neu, A. G. Peeters, G. V. Pereverzev,<br />
A. Stäbler, J. Stober, W. Suttrop and ASDEX Upgrade Team:<br />
The performance of improved H-modes at ASDEX Upgrade<br />
and projection to ITER. Nuclear Fusion 47, 1485-1498 (<strong>2007</strong>).<br />
Soddemann, T.: Science Gateways to DEISA: User requirements,<br />
technologies, and the material science and plasma<br />
physics gateway. Concurrency and Computing: Practice and<br />
Experience 19, 839-850 (<strong>2007</strong>).<br />
Spring, A., H. Laqua and J. Schacht: User control interface<br />
for W7-X plasma operation. Fusion Engineering and Design 82,<br />
1002-1007 (<strong>2007</strong>).<br />
Publications<br />
135<br />
Stan-Sion, C., J. Roth, K. Krieger, M. Enachescu, K. Ertl,<br />
V. Lazarev, H. Reithmeier and E. Nolte: AMS – Sensitive<br />
tool used as nuclear safeguard and to diagnose fusion experiments.<br />
Nuclear Instruments and Methods in Physics<br />
Research B: Beam Interaction with Materials and Atoms 259,<br />
694-701 (<strong>2007</strong>).<br />
Starke, P., C. Adelhelm and M. Balden: Erosion Behaviour<br />
of Metal-Doped Carbon Layers in Deuterium Low Pressure<br />
Plasmas and the Determination by Optical Emission Spectroscopy.<br />
Contributions to Plasma Physics 47, 530-536 (<strong>2007</strong>).<br />
Stober, J., A. C. C. Sips, C. Angioni, C. B. Forest, O. Gruber,<br />
J. Hobirk, L. D. Horton, C. F. Maggi, M. Maraschek, P. Martin,<br />
P. J. McCarthy, V. Mertens, Y.-S. Na, M. Reich, A. Stäbler,<br />
G. Tardini, H. Zohm and ASDEX Upgrade Team: The role of<br />
the current profile in the improved H-mode scenario in<br />
ASDEX Upgrade. Nuclear Fusion 47, 728-737 (<strong>2007</strong>).<br />
Strintzi, D. and F. Jenko: On the relation between secondary<br />
and modulational instabilities. Physics of Plasmas 14, 042305<br />
(<strong>2007</strong>).<br />
Sugiyama, K., T. Hayshi, K. Krieger, M. Mayer, K. Masaki,<br />
N. Miya and T. Tanabe: Ion Beam analysis of H/D retention<br />
in the near surface layers of JT-60U plasma facing wall tiles.<br />
Journal of Nuclear Materials 363-365, 949-954 (<strong>2007</strong>).<br />
Taccogna, F., S. Longo, M. Capitelli and R. Schneider:<br />
Particle-in-Cell Simulation of Stationary Plasma Thruster.<br />
Contributions to Plasma Physics 47, 635-656 (<strong>2007</strong>).<br />
Taccogna, F., R. Schneider, U. Fantz, S. Longo and M. Capitelli:<br />
Study of volume and surface effects in pure hydrogen discharges.<br />
Production and Neutralization of Negative Ions and<br />
Beams. (Ed.) M. P. Stockli. AIP Conference Proceedings 925.<br />
American <strong>Institut</strong>e of Physics, Melville, NY (<strong>2007</strong>) 20-30.<br />
Taccogna, F., R. Schneider, S. Longo and M. Capitelli:<br />
Modeling of a negative ion source I. Gas kinetics and dynamics<br />
in the expansion region. Physics of Plasmas 14, 073503 (<strong>2007</strong>).<br />
Taccogna, F., R. Schneider, K. Matyash, S. Longo, M. Capitelli<br />
and D. Tskhakaya: Negative ion production near a divertor<br />
plate. Journal of Nuclear Materials 363-365, 437-442 (<strong>2007</strong>).<br />
Takeiri, Y., O. Kaneko, K. Tsumori, U. Fantz, K. Ikeda, K. Nagaoka,<br />
M. Osakabe, Y. Oka, E. Asano, T. Kondo, M. Sato, M. Shibuya<br />
and S. Komada: High-power negative ion sources for neutral<br />
beam injectors in large helical device. Production and Neutralization<br />
of Negative Ions and Beams. (Ed.) M. P. Stockli. AIP<br />
Conference Proceedings 925. American <strong>Institut</strong>e of Physics,<br />
Melville, NY (<strong>2007</strong>) 211-223.
Tala, T., K. Crombe, P. C. De Vries, J. Ferreira, P. Mantica,<br />
A. G. Peeters, Y. Andrew, R. Budny, G. Corrigan, A. Eriksson,<br />
X. Garbet, C. Giroud, M.-D. Hua, H. Nordman, V. Naulin,<br />
M. F. F. Nave, V. Parail, K. Rantamäki, B. D. Scott, P. Strand,<br />
G. Tardini, A. Thyagaraja, J. Weiland, K.-D. Zastrow and<br />
JET-EFDA Contributors: Toroidal and poloidal momentum<br />
transport studies in tokamaks. Invited Paper. Plasma Physics<br />
and Controlled Fusion 49, B291-B302 (<strong>2007</strong>).<br />
Tambach, S. and C. Hennig: Wie zuverlässig ist der Empfang<br />
von Netzwerkpaketen bei der Verwendung des Transportprotokolls<br />
UDP? Informatik-Spektrum 30, 84-90 (<strong>2007</strong>).<br />
Tardini, G., J. Hobirk, V. Igochine, C. V. Maggi, P. Martin,<br />
D. McCune, A. G. Peeters, A. C. C. Sips, A. Stäbler, J. Stober<br />
and ASDEX Upgrade Team: Thermal ions dilution and ITG<br />
suppression in ASDEX Upgrade ion ITBs. Nuclear Fusion 47,<br />
280-287 (<strong>2007</strong>).<br />
Tasso, H. and G. N. Throumoulopoulos: On the existence of<br />
resistive magnetohydrodynamic equilibria. (Letter to the<br />
Editor). Journal of Plasma Physics 73, 285-287 (<strong>2007</strong>).<br />
Tasso, H. and G. N. Throumoulopoulos: On the Vlasov approach<br />
to tokamak equilibria with flow. Journal of Physics A:<br />
Mathematical and Theoretical 40, F631-F637 (<strong>2007</strong>).<br />
Thehos, K.: <strong>IPP</strong> 2006 – Das <strong>Max</strong>-<strong>Planck</strong>-<strong>Institut</strong> <strong>für</strong> <strong>Plasmaphysik</strong><br />
im Jahresrückblick. <strong>Max</strong>-<strong>Planck</strong>-<strong>Institut</strong> <strong>für</strong> <strong>Plasmaphysik</strong>.<br />
Pressestelle, Garching bei München (<strong>2007</strong>), 31 p.<br />
Throumoulopoulos, G. N., H. Weitzner and H. Tasso: On<br />
nonexistence of tokamak equilibria with purely poloidal<br />
flow. Physics of Plasmas 13, 122501 (<strong>2007</strong>).<br />
Thumm, M., S. Alberti, A. Arnold, P. Brand, H. Braune, G. Dammertz,<br />
V. Erckmann, G. Gantenbein, E. Giguet, R. Heidinger, J. P. Hogge,<br />
S. Illy, W. Kasparek, H. P. Laqua, F. Legrand, W. Leonhardt,<br />
C. Lievin, G. Michel, G. Neffe, B. Piosczyk, M. Schmid, K. Schwörer<br />
and M. Q. Tran: EU megawatt-class 140 GHz CW gyrotron.<br />
IEEE Transactions on Plasma Science 35, 143-153 (<strong>2007</strong>).<br />
Tsalas, M., D. Coster, C. Fuchs, A. Herrmann, A. Kallenbach,<br />
H. W. Müller, J. Neuhauser, V. Rohde, N. Tsois and ASDEX<br />
Upgrade Team: In-out divertor flow asymmetries during<br />
ELMs in ASDEX Upgrade H-mode plasmas. Journal of<br />
Nuclear Materials 363-365, 1093-1098 (<strong>2007</strong>).<br />
Tsalas, M., A. Herrmann, A. Kallenbach, H. W. Müller,<br />
J. Neuhauser, V. Rohde, N. Tsois, M. Wischmeier and ASDEX<br />
Upgrade Team: Divertor plasma flows near the lower x-point in<br />
ASDEX Upgrade. Plasma Physics and Controlled Fusion 49,<br />
857-872 (<strong>2007</strong>).<br />
Publications<br />
136<br />
Tskhakaya, D., K. Matyash, R. Schneider and F. Taccogna:<br />
The Particle-In-Cell Method. Contributions to Plasma<br />
Physics 47, 563-594 (<strong>2007</strong>).<br />
Tskhakaya, D. and R. Schneider: Optimization of PIC codes<br />
by improved memory management. Journal of Computational<br />
Physics 225, 829-839 (<strong>2007</strong>).<br />
Turkin, Y., C. D. Beidler, A. Dinklage, J. Geiger, H. Maaßberg,<br />
N. B. Marushchenko and W7-X Team: Transport simulations<br />
for W7-X. Stellarator News, 4-8 (<strong>2007</strong>).<br />
http://www.ornl.gov/sci/fed/stelnews/sn107.pdf<br />
Tykhyy, A. V., Y. I. Kolesnichenko, Y. V. Yakovenko, A. Weller and<br />
A. Werner: Mitigation of stochastic diffusion losses in optimized<br />
stellarators. Plasma Physics and Controlled Fusion 49,<br />
703-711 (<strong>2007</strong>).<br />
Vainonen-Ahlgren, E., J. Likonen, T. Renvall, V. Rohde,<br />
M. Mayer and ASDEX Upgrade Team: Migration of 13 C and<br />
deposition at ASDEX Upgrade. Journal of Nuclear Materials<br />
363-365, 270-275 (<strong>2007</strong>).<br />
Veres, G., R. A. Pitts, M. Wischmeier, B. Gulejova, J. Horacek<br />
and S. Kalvin: Radiation distributions in TCV. Journal of<br />
Nuclear Materials 363-365, 1104-1109 (<strong>2007</strong>).<br />
Verhoeven, A. G. A., W. A. Bongers, A. Bruschi, S. Cirant,<br />
I. Danilov, B. S. Q. Elzendoorn, A. Fernandez, M. F. Graswinckel,<br />
R. Heidinger, M. Henderson, J. Jamar, W. Kasparek, O. G. Kruijt,<br />
B. Lamers, B. Plaum, D. M. S. Ronden, G. Saibene, F. C. Schüller,<br />
E. Westerhof and H. Zohm: Design of the remote-steering<br />
ITER ECRH upper-port launcher. Fusion Engineering and<br />
Design 82, 627-632 (<strong>2007</strong>).<br />
Vermare, L., F. Ryter, C. Angioni, A. G. Peeters, J. Stober,<br />
R. Bilato, L. D. Horton, B. Kurzan, C. F. Maggi, H. Meister,<br />
J. Schirmer, G. Tardini and ASDEX Upgrade Team: Study of<br />
the β dependence of confinement and heat transport in<br />
ASDEX Upgrade. Nuclear Fusion 47, 490-497 (<strong>2007</strong>).<br />
Von Toussaint, U. and S. Gori: Deconvolution using thinplate<br />
splines. Bayesian Inference and <strong>Max</strong>imum Entropy<br />
Methods in Science and Engineering: 27 th International<br />
Workshop on Bayesian Inference and <strong>Max</strong>imum Entropy<br />
Methods in Science and Engineering. (Eds.) K. H. Knuth,<br />
A. Caticha, J. L. Center, A. Giffin, C. C. Rodriguez. AIP<br />
Conference Proceedings 954. American <strong>Institut</strong>e of Physics,<br />
Melville, NY, 212-220 (<strong>2007</strong>).<br />
Vrancken, M., M.-L. Mayoral, T. Blackman, V. V. Bobkov,<br />
D. Child, P. Dumortier, F. Durodie, M. Evrard, R. H. Goulding,<br />
M. Graham, S. Huygen, P. U. Lamalle, F. Louche, A. M. Messiaen,
I. Monakhov, M. P. S. Nightingale, J.-M. Noterdaeme,<br />
J. Ongena, D. Stork, M. Vervier, A. Walden, A. Whitehurst and<br />
JET-EFDA Contributors: Recent ICRF developments at JET.<br />
Fusion Engineering and Design 82, 873-880 (<strong>2007</strong>).<br />
Wagner, D., F. Leuterer, A. Manini, F. Monaco, M. Münich,<br />
F. Ryter, H. Schütz, J. Stober, H. Zohm, T. Franke, I. Danilov,<br />
R. Heidinger, M. Thumm, G. Gantenbein, W. Kasparek, C. Lechte,<br />
A. Litvak, G. Denisov, E. Tai, L. Popov, V. Nichiporenko,<br />
V. Myasnikov, E. Solyanova, S. Malygin, F. Meo and P. Woskov:<br />
The New Multifrequency Electron Cyclotron Resonance<br />
Heating System for ASDEX Upgrade. Fusion Science and<br />
Technology 52, 313-320 (<strong>2007</strong>).<br />
Wagner, F.: About the European Physical Society (EPS).<br />
Butsuri 62, 536-540 (<strong>2007</strong>).<br />
Wagner, F.: On the impact of experts. Europhysics News 38, 4,<br />
5-6 (<strong>2007</strong>).<br />
Wagner, F.: A quarter-century of H-mode studies. Invited Paper.<br />
Plasma Physics and Controlled Fusion 49, B1-B33 (<strong>2007</strong>).<br />
Wagner, F.: Is truth still of value? Europhysics News 38, 5,<br />
5-6 (<strong>2007</strong>).<br />
Wagner, F.: My views and programme. Europhysics News 38, 3,<br />
5-9 (<strong>2007</strong>).<br />
Waldmann, O., H. Meyer and G. Fußmann: Anomalous<br />
Diffusion in a Linear Plasma Generator. Contributions to<br />
Plasma Physics 47, 691-702 (<strong>2007</strong>).<br />
Wanner, M., C. Sborchia, K. Riße, H. Viebke and J. Baldzuhn:<br />
Experience gained during manufacture and testing of the<br />
W7-X superconducting magnets. Fusion Engineering and<br />
Design 82, 1379-1384 (<strong>2007</strong>).<br />
Warrier, M., R. Schneider, E. Salonen and K. Nordlund:<br />
Effect of the porous structure of graphite on atomic hydrogen<br />
diffusion and inventory. Nuclear Fusion 47, 1656-1663 (<strong>2007</strong>).<br />
Wegener, L.: Wendelstein 7-X at the transition to assembly.<br />
Atomwirtschaft 52, 8/9, 558-563 (<strong>2007</strong>).<br />
Wenzel, U., D. Schröder and G. Fußmann: Appearance of a H α<br />
Minimum at the Onset of Net Recombination in Hydrogen<br />
Plasmas. Contributions to Plasma Physics 47, 451-457 (<strong>2007</strong>).<br />
Wenzel, U., H. Thomsen and P. Grigull: Carbon influx from<br />
the island divertor of the Wendelstein-7AS stellarator.<br />
Journal of Nuclear Materials 363-365, 713-717 (<strong>2007</strong>).<br />
Publications<br />
137<br />
Wiltner, A., F. Kost, S. Lindig and C. Linsmeier: Structural<br />
investigation of the Be-W intermetallic system. Physica<br />
Scripta T128, 133-136 (<strong>2007</strong>).<br />
Windisch, T., O. Grulke and T. Klinger: Radially propagating<br />
turbulent structures in a linear helicon plasma device.<br />
Journal of Nuclear Materials 363-365, 586-590 (<strong>2007</strong>).<br />
Winter, B., E. F. Aziz, U. Hergenhahn, M. Faubel and I. V. Hertel:<br />
Hydrogen bonds in liquid water studied by photoelectron<br />
spectroscopy. Journal of Chemical Physics 126, 124504<br />
(<strong>2007</strong>).<br />
Winter, B., U. Hergenhahn, M. Faubel, O. Björneholm and<br />
I. V. Hertel: Hydrogen bonding in liquid water probed by<br />
resonant Auger-electron spectroscopy. Journal of Chemical<br />
Physics 127, 094501 (<strong>2007</strong>).<br />
Wischmeier, M., A. Kallenbach, A. V. Chankin, D. P. Coster,<br />
T. Eich, A. Herrmann, H. W. Müller and ASDEX Upgrade<br />
Team: High recycling outer divertor regimes after type-I<br />
ELMs at high density in ASDEX Upgrade. Journal of Nuclear<br />
Materials 363-365, 448-452 (<strong>2007</strong>).<br />
Wong, C., D. Rudakov, J. Allain, R. Bastasz, N. Brooks,<br />
J. Brooks, R. Doerner, T. Evans, A. Hassanein, W. Jacob,<br />
K. Krieger, A. Litnovsky, A. McLean, V. Philipps, A. Pigarov,<br />
W. Wampler, J. Watkins, W. West, J. Whaley and P. Wienhold:<br />
Divertor and Midplane Materials Evaluation System in<br />
DIII-D. Journal of Nuclear Materials 363-365, 276-281<br />
(<strong>2007</strong>).<br />
Wünderlich, D., R. Gutser and U. Fantz: Influence of Magnetic<br />
Fields and Biasing on the Plasma of a RF Driven<br />
Negative Ion Source. Production and Neutralization of Negative<br />
Ions and Beams. (Ed.) M. P. Stockli. AIP Conference<br />
Proceedings 925. American <strong>Institut</strong>e of Physics, Melville, NY,<br />
46-57 (<strong>2007</strong>).<br />
Xanthopoulos, P. and F. Jenko: Gyrokinetic analysis of linear<br />
microinstabilities for the stellarator Wendelstein 7-X. Physics<br />
of Plasmas 14, 042501 (<strong>2007</strong>).<br />
Xanthopoulos, P., F. Merz, T. Görler and F. Jenko: Nonlinear<br />
gyrokinetic simulations of ion-temperature-gradient<br />
turbulence for the optimized stellarator Wendelstein 7-X.<br />
Physical Review Letters 99, 035002 (<strong>2007</strong>).<br />
Yakovenko, Y., A. Weller, A. Werner, S. Zegenhagen, O. P. Fesenyuk<br />
and Y. Kolesnichenko: Poloidal trapping of the high-frequency<br />
Alfvén continuum and eigenmodes in stellarators.<br />
Plasma Physics and Controlled Fusion 49, 535-558 (<strong>2007</strong>).
Yamamoto, S., K. Nagasaki, Y. Suzuki, T. Mizuuchi, H. Okada,<br />
S. Kobayashi, B. Blackwell, K. Kondo, G. Motojima, N. Nakajima,<br />
Y. Nakamura, C. Nührenberg, Y. Torii, S. Watanabe and F. Sano:<br />
Observation of Magnetohydrodynamic Instabilities in<br />
Heliotron J Plasmas. Fusion Science and Technology 51,<br />
92-96 (<strong>2007</strong>).<br />
Yao, Z., A. Suzuki, D. Levchuk and T. Terai: SiC coating by<br />
RF sputtering as tritium permeation barrier for fusion blanket.<br />
Fusion Science and Technology 52, 865-869 (<strong>2007</strong>).<br />
Yokoyama, M., H. Maaßberg, C. D. Beidler, V. Tribaldos, K. Ida,<br />
T. Estrada, F. Castejon, A. Fujisawa, T. Minami, T. Shimozuma,<br />
Y. Takeiri, A. Dinklage, S. Murakami and H. Yamada: Core<br />
electron-root confinement (CERC) in helical plasmas. Nuclear<br />
Fusion 47, 1213-1219 (<strong>2007</strong>).<br />
Yu, Q.: Heat diffusion across a local stochastic magnetic<br />
field. Nuclear Fusion 47, 1244-1249 (<strong>2007</strong>).<br />
Zohm, H.: 21 st IAEA Fusion Energy Conference: Summary<br />
of Sessions EX/D, EX/S and EX/W. Nuclear Fusion 47,<br />
S521-S528 (<strong>2007</strong>).<br />
Zohm, H.: Recent Experimental Progress in Electron Cyclotron<br />
Resonance Heating and Electron Cyclotron Current Drive in<br />
Magnetically Confined Fusion Plasmas. Fusion Science and<br />
Technology 52, 134-144 (<strong>2007</strong>).<br />
Zohm, H., G. Gantenbein, F. Leuterer, A. Manini, M. Maraschek,<br />
Q. Yu and ASDEX Upgrade Team: Control of MHD Instabilities<br />
by ECCD: ASDEX Upgrade Results and Impliations<br />
for ITER. Nuclear Fusion 47, 228-232 (<strong>2007</strong>).<br />
Zohm, H., G. Gantenbein, F. Leuterer, M. Maraschek, E. Poli,<br />
L. Urso and ASDEX Upgrade Team: Control of NTMs by<br />
ECCD on ASDEX Upgrade in view of ITER application.<br />
Invited Paper. Plasma Physics and Controlled Fusion 49,<br />
B341-B348 (<strong>2007</strong>).<br />
Zweben, S. J., J. A. Boedo, O. Grulke, C. Hidalgo, B. LaBombard,<br />
R. J. Maqueda, P. Scarin and J. L. Terry: Edge turbulence<br />
measurements in toroidal fusion devices. Plasma Physics<br />
and Controlled Fusion 49, S1-S23 (<strong>2007</strong>).<br />
Publications<br />
138<br />
Conference Papers<br />
Angioni, C., A. Manini, A. G. Peeters, F. Ryter, R. Dux, A. Jacchia,<br />
C. F. Maggi, R. Neu, W. Suttrop, G. Tardini and ASDEX<br />
Upgrade Team: Theoretical understanding of core transport<br />
phenomena in ASDEX Upgrade. Fusion Energy 2006, International<br />
Atomic Energy Agency, Vienna, EX/8-5Rb (<strong>2007</strong>).<br />
Antar, G. Y., M. Tsalas, E. Wolfrum, V. Rohde, B. Scott and<br />
J. Neuhauser: Comparing Turbulence in L and H-mode plasmas<br />
in the Scrape-off Layer of the ASDEX-Upgrade Tokamak.<br />
34 th European Physical Society Conference on Plasma<br />
Physics. Contributed Papers, (Eds.) P. Gasior, J. Wolowski.<br />
ECA 31 F. European Physical Society, Geneva, P-1.076<br />
(<strong>2007</strong>).<br />
Atanasiu, C. V., S. Günter, A. Moraru and L.E. Zakharov:<br />
Resistive Wall Modes Stabilization in the Presence of 3D Wall<br />
Structures. 34 th European Physical Society Conference on Plasma<br />
Physics. Contributed Papers, (Eds.) P. Gasior, J. Wolowski.<br />
ECA 31 F. European Physical Society, Geneva, P-4.086<br />
(<strong>2007</strong>).<br />
Bertelli, N., G. V. Pereverzev and E. Poli: Beam Tracing<br />
description of LH waves in tokamaks. 34 th European Physical<br />
Society Conference on Plasma Physics. Contributed Papers,<br />
(Eds.) P. Gasior, J. Wolowski. ECA 31 F. European Physical<br />
Society, Geneva, P-5.051 (<strong>2007</strong>).<br />
Bonnin, X., D. P. Coster, M. Warrier and R. Schneider: Integrated<br />
modelling of plasma-wall interactions in tokamaks<br />
with B2.5: mixed materials, layers and coatings, bundled<br />
charge states, and hydrogen inventory. 34 th European Physical<br />
Society Conference on Plasma Physics. Contributed Papers,<br />
(Eds.) P. Gasior, J. Wolowski. ECA 31 F. European Physical<br />
Society, Geneva, P-4.036 (<strong>2007</strong>).<br />
Bovshuk, V. R., W. A. Cooper, M. I. Mikhailov, J. Nührenberg<br />
and V. D. Shafranov: Search for quasi-isodynamic configurations<br />
with diminished parallel current density. 34 th European<br />
Physical Society Conference on Plasma Physics. Contributed<br />
Papers, (Eds.) P. Gasior, J. Wolowski. ECA 31 F. European<br />
Physical Society, Geneva, P-4.103 (<strong>2007</strong>).<br />
Braune, H., P. Brand, G. Dammertz, V. Erckmann, G. Gantenbein,<br />
W. Kasparek, H. P. Laqua, W. Leonhardt, D. Mellein, G. Michel,<br />
F. Noke, F. Purps, K.-H. Schlüter, M. Schmid, M. Thumm<br />
and W7-X ECRH Teams at <strong>IPP</strong>, IPF and FZK: Extended<br />
operation of the 1 MW, CW gyrotrons for W7-X. IRMMW-THz<br />
<strong>2007</strong>: Conference Digest of the 32 nd International Conference<br />
on Infrared and Millimeter Waves, and 15 th International<br />
Conference on Terahertz Electronics, IEEE Operation Center,<br />
Piscataway, NJ, CD-ROM, 104-105 (<strong>2007</strong>).
Camplani, M., B. Cannas, A. Fanni, G. Pautasso, S. Sias,<br />
P. Sonato, M. K. Zedda and ASDEX Upgrade Team: Mapping of<br />
the ASDEX Upgrade Operational Space using Clustering Techniques.<br />
34 th European Physical Society Conference on Plasma<br />
Physics. Contributed Papers, (Eds.) P. Gasior, J. Wolowski.<br />
ECA 31 F. European Physical Society, Geneva, P-5.144 (<strong>2007</strong>).<br />
Chankin, A. V., D. P. Coster, G. Corrigan, S. K. Erents,<br />
W. Fundamenski, A. Kallenbach, K. Lackner, J. Neuhauser,<br />
R. Pitts, ASDEX Upgrade Team and JET-EFDA Contributors:<br />
Mechanisms Affecting Radial Electric Field in the Tokamak<br />
SOL. 34 th European Physical Society Conference on Plasma<br />
Physics. Contributed Papers, (Eds.) P. Gasior, J. Wolowski.<br />
ECA 31 F. European Physical Society, Geneva, P-4.029 (<strong>2007</strong>).<br />
Chankin, A. V., D. P. Coster, R. Dux, C. Fuchs, G. Haas,<br />
A. Herrmann, L. D. Horton, A. Kallenbach, M. Kaufmann,<br />
C. Konz, V. Kotov, A. S. Kukushkin, K. Lackner, H. W. Müller,<br />
J. Neuhauser, R. Pungo, M. Reich, D. Reiter, W. Schneider<br />
and ASDEX Upgrade Team: Critical issues identified by the<br />
comparison between experiment and SOLPS modelling on<br />
ASDEX Upgrade. Fusion Energy 2006, International Atomic<br />
Energy Agency, Vienna, TH/P6-15 (<strong>2007</strong>).<br />
Coster, D. P., X. Bonnin, A. Chankin, G. Corrigan, W. Fundamenski,<br />
L. Owen, T. Rognlien, S. Wiesen, R. Zagorski and JET-EFDA<br />
Contributors: Benchmarking Tokamak Edge Modelling Codes.<br />
34 th European Physical Society Conference on Plasma<br />
Physics. Contributed Papers, (Eds.) P. Gasior, J. Wolowski.<br />
ECA 31 F. European Physical Society, Geneva, P-4.026 (<strong>2007</strong>).<br />
Conway, G. D., J. Schirmer, C. Angioni, J. C. Fuchs, R. Dux,<br />
F. Jenko, E. Holzhauer, S. Klenge, B. Kurzan, A. G. Peeters,<br />
C. Maggi, E. Poli, M. Reich, F. Ryter, B. Scott, W. Suttrop,<br />
C. Tröster, E. Wolfrum, H. Zohm and ASDEX Upgrade Team:<br />
Study of turbulence and radial electric field transitions in ASDEX<br />
Upgrade using Doppler reflectometry. Fusion Energy 2006,<br />
International Atomic Energy Agency, Vienna, EX/2-1 (<strong>2007</strong>).<br />
Conway, G. D., C. Tröster, J. Schirmer, C. Angioni, E. Holzhauer,<br />
F. Jenko, F. Merz, E. Poli, B. Scott, W. Suttrop and ASDEX<br />
Upgrade Team: Doppler reflectometry on ASDEX Upgrade:<br />
Foundations and latest results. 8 th International Reflectometry<br />
Workshop (IRW8), Open Access, 30-36 (<strong>2007</strong>).<br />
http://plasma.ioffe.ru/irw8/proceedings.html<br />
Conway, G. D., C. Tröster, B. Scott, K. Hallatschek and ASDEX<br />
Upgrade Team: Observations on Geodesic Acoustic Mode<br />
scaling and core localization in ASDEX Upgrade using<br />
Doppler reflectometry. 34 th European Physical Society<br />
Conference on Plasma Physics. Contributed Papers, (Eds.)<br />
P. Gasior, J. Wolowski. ECA 31 F. European Physical Society,<br />
Geneva, O-4.009 (<strong>2007</strong>).<br />
Publications<br />
139<br />
Da Graca, S., G. D. Conway, P. Lauber, M. Maraschek, D. Borba,<br />
S. Günter, L. Cupido, K. Sassenberg, F. Serra, M. E. Manso,<br />
CFN Reflectometry Group and ASDEX Upgrade Team:<br />
Studies of fast particle modes in ASDEX Upgrade using<br />
reflectometry and comparison with theoretical prediction.<br />
34 th European Physical Society Conference on Plasma<br />
Physics. Contributed Papers, (Eds.) P. Gasior, J. Wolowski.<br />
ECA 31 F. European Physical Society, Geneva, P-5,096 (<strong>2007</strong>).<br />
Dinklage, A., H. Maaßberg, R. Preuss, Y. Turkin, H. Yamada,<br />
E. Ascasibar, C. D. Beidler, J. H. Harris, A. Kus, S. Murakami,<br />
S. Okamura, F. Sano, U. Stroth, Y. Suzuki, J. Talmadge,<br />
V. Tribaldos, K. Y. Watanabe and A. Werner: Physical model<br />
assessment of the energy confinement time scaling in stellarators.<br />
Fusion Energy 2006, International Atomic Energy<br />
Agency, Vienna, EX/P7-1 (<strong>2007</strong>).<br />
Dodt, D., A. Dinklage, R. Fischer and R. Preuss: Assessment<br />
of Electron Energy Distributions in Discharges by Optical Emission<br />
Spectroscopy. Bayesian Inference and <strong>Max</strong>imum Entropy<br />
Methods in Science and Engineering: 27 th International<br />
Workshop on Bayesian Inference and <strong>Max</strong>imum Entropy<br />
Methods in Science and Engineering. (Eds.) K. H. Knuth,<br />
A. Caticha, J. L. Center, A. Giffin, C. C. Rodriguez. AIP Conference<br />
Proceedings 954. American <strong>Institut</strong>e of Physics,<br />
Melville, NY, 468-475 (<strong>2007</strong>).<br />
Doerner, R., M. Baldwin, G. Federici, J. Hanna, A. Loarte,<br />
D. Nishijima, R. Pugno, J. Roth, K. Schmid, G. Tynan, A. Wiltner<br />
and D. Whyte: Beryllium containing plasma interactions<br />
with ITER materials. Fusion Energy 2006, International<br />
Atomic Energy Agency, Vienna, IT/P1-20 (<strong>2007</strong>).<br />
Dux, R., R. Neu, V. Bobkov, H. Greuner, O. Gruber, C. Hopf,<br />
A. Kallenbach, T. Pütterich, V. Rohde and ASDEX Upgrade<br />
Team: Tungsten as first wall material in ASDEX Upgrade.<br />
Fusion Energy 2006, International Atomic Energy Agency,<br />
Vienna, EX/3-3Ra (<strong>2007</strong>).<br />
Dux, R., R. Pugno, T. Pütterich, V. Bobkov, A. Kallenbach,<br />
R. Neu and ASDEX Upgrade Team: Impurity Influx in the<br />
All Tungsten ASDEX Upgrade. 34 th European Physical<br />
Society Conference on Plasma Physics. Contributed Papers,<br />
(Eds.) P. Gasior, J. Wolowski. ECA 31 F. European Physical<br />
Society, Geneva, P-1.052 (<strong>2007</strong>).<br />
Eich, T., A. Kallenbach, A. Herrmann, J. C. Fuchs, C. S. Chang,<br />
D. Tskhakaya and ASDEX Upgrade Team: ELM divertor<br />
heat load in forward and reversed field in ASDEX Upgrade.<br />
34 th European Physical Society Conference on Plasma<br />
Physics. Contributed Papers, (Eds.) P. Gasior, J. Wolowski.<br />
ECA 31 F. European Physical Society, Geneva, P-2.017<br />
(<strong>2007</strong>).
Erckmann, V., P. Brand, H. Braune, G. Dammertz, G. Gantenbein,<br />
W. Kasparek, H. P. Laqua, G. Michel, M. Schmid, M. Thumm,<br />
M. Weißgerber, W7X ECRH Team at <strong>IPP</strong> Greifswald, W7-X<br />
Team at FZK Karlsruhe and W7-X Team at IPF Stuttgart: The<br />
W7-X ECRH Plant: Recent Achievements. Radio Frequency<br />
Power in Plasmas: 17 th Topical Conference on Radio Frequency<br />
Power in Plasmas. (Eds.) P. M. Ryan, D. A. Rasmussen. AIP<br />
Conference Proceedings 933. American <strong>Institut</strong>e of Physics,<br />
Melville, NY, 421-424 (<strong>2007</strong>).<br />
Erckmann, V., P. Brand, H. Braune, G. Dammertz, G. Gantenbein,<br />
W. Kasparek, H. P. Laqua, G. Michel, M. Thumm, M. Weißgerber,<br />
W7-X ECRH Team at <strong>IPP</strong> Greifswald, W7-X ECRH Team at<br />
FZK Karlsruhe and W7-X ECRH Team at IPF Stuttgart: The<br />
140 GHz, 10 MW, CW ECRH Plant for W7-X: A Training<br />
Field for ITER. Fusion Energy 2006, International Atomic<br />
Energy Agency, Vienna, IT/2-4Rd (<strong>2007</strong>).<br />
Fable, E., C. Angioni, A. Bottino, S. Brunner, T. Dannert,<br />
F. Jenko and O. Sauter: The role of electron-driven microinstabilities<br />
in particle transport during electron Internal Transport<br />
Barriers. 34 th European Physical Society Conference on Plasma<br />
Physics. Contributed Papers, (Eds.) P. Gasior, J. Wolowski.<br />
ECA 31 F. European Physical Society, Geneva, P-1.100 (<strong>2007</strong>).<br />
Feist, J. H. and Project Team W7-X: Status of Wendelstein<br />
7-X construction. 34 th European Physical Society Conference<br />
on Plasma Physics. Contributed Papers, (Eds.) P. Gasior,<br />
J. Wolowski. ECA 31 F. European Physical Society, Geneva,<br />
P-1.161 (<strong>2007</strong>).<br />
Fischer, R., E. Wolfrum, J. Schweinzer and ASDEX Upgrade<br />
Team: Probabilistic Lithium beam data analysis. 34 th European<br />
Physical Society Conference on Plasma Physics. Contributed<br />
Papers, (Eds.) P. Gasior, J. Wolowski. ECA 31 F.<br />
European Physical Society, Geneva, P-5.077 (<strong>2007</strong>).<br />
Franzen, P., H. D. Falter, U. Fantz, W. Kraus, M. Berger,<br />
S. Christ, M. Fröschle, R. Gutser, B. Heinemann, S. Hilbert,<br />
S. Leyer, A. Lümkemann, C. Martens, P. McNeely, R. Riedl,<br />
E. Speth and D. Wünderlich: Progress of the Development<br />
of the <strong>IPP</strong> RF Negative Ion Source for the ITER Neutral<br />
Beam System. Fusion Energy 2006, International Atomic<br />
Energy Agency, Vienna, IT/2-3Rc (<strong>2007</strong>).<br />
Franzen, P., U. Fantz, W. Kraus, M. Berger, S. Christ-Koch,<br />
M. Fröschle, B. Heinemann, F. Maisberger, C. Martens,<br />
P. McNeely, R. Riedl, E. Speth, D. Wünderlich and T. Zacharias:<br />
Homogeneity and long pulse operation of the <strong>IPP</strong> RF source<br />
for the ITER NBI system. 34 th European Physical Society<br />
Conference on Plasma Physics. Contributed Papers, (Eds.)<br />
P. Gasior, J. Wolowski. ECA 31 F. European Physical Society,<br />
Geneva, P-4.182 (<strong>2007</strong>).<br />
Publications<br />
140<br />
Frank, D. and T. Soddemann: Interoperable Job Submission<br />
and Management with GridSAM, JMEA and UNICORE.<br />
German e-Science (GeS) Conference. <strong>Max</strong> <strong>Planck</strong> Digital<br />
Library, München (<strong>2007</strong>).<br />
http://www.ges<strong>2007</strong>.de<br />
Gal, K., P. T. Lang, J. Neuhauser and ASDEX Upgrade Team:<br />
Pellet Induced Perturbations in the Plasma Edge. 34 th European<br />
Physical Society Conference on Plasma Physics.<br />
Contributed Papers, (Eds.) P. Gasior, J. Wolowski. ECA 31 F.<br />
European Physical Society, Geneva, P-4.080 (<strong>2007</strong>).<br />
Gantenbein, G., S. Alberti, A. Arnold, G. Dammertz, V. Erckmann,<br />
E. Giguet, R. Heidinger, J. P. Hogge, S. Illy, W. Kasparek,<br />
H. P. Laqua, F. Legrand, W. Leonhardt, C. Liévin, G. Michel,<br />
G. Neffe, B. Piosczyk, M. Schmid, M. Thumm and M. Q. Tran:<br />
Experimental results of the 1-MW,140-GHz, CW Gyrotron<br />
for W7-X. Fusion Energy 2006, International Atomic Energy<br />
Agency, Vienna, IT/2-4Re (<strong>2007</strong>).<br />
Gantenbein, G., H. Braune, G. Dammertz, S. Alberti, V. Erckmann,<br />
J. P. Hogge, S. Illy, W. Kasparek, H. P. Laqua, F. Legrand,<br />
W. Leonhardt, C. Liévin, G. Michel, G. Neffe, F. Noke,<br />
B. Piosczyk, F. Purps, M. Schmid, M. Thumm and M. Q. Tran:<br />
High-power experiments with 140 GHz series gyrotrons for W7-X.<br />
Proceedings of the 8 th IEEE International Vacuum Electronics<br />
Conference. IEEE Operation Center, Piscataway, NJ, 41-42<br />
(<strong>2007</strong>).<br />
Gantenbein, G., G. Dammertz, V. Erckmann, S. Illy, W. Kasparek,<br />
C. Lechte, F. Legrand, G. Lietaer, C. Liévin, B. Piosczyk,<br />
M. Schmid and M. Thumm: Experimental results on highpower<br />
gyrotrons for the stellarator W7-X. Conference Digest<br />
of the 32 nd International Conference on Infrared and Millimeter<br />
Waves, and 15 th International Conference on Terahertz<br />
Electronics, IEEE Operation Center, Piscataway, NJ, CD-ROM,<br />
102-103 (<strong>2007</strong>).<br />
Giannone, L., W. Schneider, P. J. McCarthy, A. C. C. Sips,<br />
W. Treutterer, J. C. Fuchs, J. Stober and ASDEX Upgrade<br />
Team: Real time magnetic flux surface positions for ASDEX<br />
Upgrade. 34 th European Physical Society Conference on Plasma<br />
Physics. Contributed Papers, (Eds.) P. Gasior, J. Wolowski.<br />
ECA 31 F. European Physical Society, Geneva, P-1.113<br />
(<strong>2007</strong>).<br />
Gobbin, M., P. Martin, L. Marrelli, H.-U. Fahrbach, M. Garcia-<br />
Munoz, S. Günter, V. Igochine, M. Maraschek, M. Reich,<br />
R. B. White and AUG Team: Numerical study of fast ions<br />
transport induced by MHD instabilities in the tokamak. 34 th<br />
European Physical Society Conference on Plasma Physics.<br />
Contributed Papers, (Eds.) P. Gasior, J. Wolowski. ECA 31 F.<br />
European Physical Society, Geneva, P-4.073 (<strong>2007</strong>).
Groth, M., N. H. Brooks, D. P. Coster, R. Dux, M. E. Fenstermacher,<br />
R. J. Groebner, J. Harhausen, A. Kallenbach, C. J. Lasnier,<br />
A. W. Leonard, W. H. Meyer, H. W. Müller, T. H. Osborne,<br />
M. Reich, G. D. Porter, R. Pugno, M. E. Rensink, D.L. Rudakov,<br />
M. Tsalas, J. G. Watkins, M. Wischmeier, E. Wolfrum, ASDEX<br />
Upgrade Team and DIII-D Team: Effect of Divertor<br />
Geometry on Fueling Profile of the Core Plasma in Low-<br />
Density, Ohmic Plasmas in ASDEX Upgrade and DIII-D.<br />
34 th European Physical Society Conference on Plasma Physics.<br />
Contributed Papers, (Eds.) P. Gasior, J. Wolowski. ECA 31 F.<br />
European Physical Society, Geneva, P-1.039 (<strong>2007</strong>).<br />
Gruber, O. and ASDEX Upgrade Team: Overview of ASDEX<br />
Upgrade results. Invited paper. Fusion Energy 2006,<br />
International Atomic Energy Agency, Vienna, OV/2-2 (<strong>2007</strong>).<br />
Günter, S., G. Conway, C. Forest, H.-U. Fahrbach, M. Garcia<br />
Munoz, S. da Graca, T. Hauff, J. Hobirk, V. Igochine, F. Jenko,<br />
K. Lackner, P. Lauber, P. McCarthy, M. Maraschek, P. Martin,<br />
E. Poli, K. Sassenberg, E. Strumberger, G. Tardini, H. Zohm<br />
and ASDEX Upgrade Team: Fast Particle Physics on ASDEX<br />
Upgrade – Interaction of Energetic Particles with Large and<br />
Small Scale Instabilities. Fusion Energy 2006, International<br />
Atomic Energy Agency, Vienna, EX/6-1 (<strong>2007</strong>).<br />
Gulejova, B., R. A. Pitts, X. Bonnin, D. Coster, R. Behn,<br />
J. Horacek, J. Marki and TCV Team: Time-dependent modelling<br />
of ELMing H-mode at TCV with SOLPS5. 34 th European<br />
Physical Society Conference on Plasma Physics. Contributed<br />
Papers, (Eds.) P. Gasior, J. Wolowski. ECA 31 F.<br />
European Physical Society, Geneva, P-1.044 (<strong>2007</strong>).<br />
Haange, R. and W7-X Team: Experience Gained during Fabrication<br />
and Construction of Wendelstein 7-X. Fusion Energy 2006,<br />
International Atomic Energy Agency, Vienna, FT/2-3 (<strong>2007</strong>).<br />
Hallatschek, K.: News from the Geodesic Acoustic Mode:<br />
Magnetic Shear-, q-, and Geometry Effect. Fusion Energy 2006,<br />
International Atomic Energy Agency, Vienna, TH/P2-6 (<strong>2007</strong>).<br />
Harhausen, J., J. C. Fuchs, A. Kallenbach, W. Schustereder,<br />
M. Wischmeier and ASDEX Upgrade Team: Interpretation<br />
of H α Imaging Diagnostics Data on ASDEX Upgrade. 34 th<br />
European Physical Society Conference on Plasma Physics.<br />
Contributed Papers, (Eds.) P. Gasior, J. Wolowski. ECA 31 F.<br />
European Physical Society, Geneva, P-2.037 (<strong>2007</strong>).<br />
Hellsten, T., M. Laxaback, T. Bergkvist, T. Johnson, M. Mantsinen,<br />
G. Matthews, F. Meo, F. Nguyen, J.-M. Noterdaeme, C. C. Petty,<br />
T. Tala, D. Van Eester, P. Andrew, P. Beaumont, V. Bobkov,<br />
M. Brix, J. Brzozowski, L.-G. Eriksson, C. Giroud, E. Joffrin,<br />
V. Kiptily, J. Mailloux, M.-L. Mayoral, I. Monakhov, J. Ongena,<br />
R. Sartori, A. Stäbler, E. Rachlew, E. Tennfors, A. Tuccillo,<br />
Publications<br />
141<br />
A. Walden, K.-D. Zastrow and JET-EFDA Contributors:<br />
Fast Wave Current Drive and Direct Electron Heating in JET<br />
ITB Plasmas. Fusion Energy 2006, International Atomic<br />
Energy Agency, Vienna, EX/P6-2 (<strong>2007</strong>).<br />
Herrmann, J. and T. Hamacher: Challenges and Opportunities<br />
of an Interconnected European and Russian Electricity<br />
Network. 9 th IAEE European Energy Conference. IAEE,<br />
Cleveland, OH, CD-ROM, 1-8 (<strong>2007</strong>).<br />
Hynönen, V., T. Kurki-Suoni, K. Sugiyama, R. Dux, A. Stäbler,<br />
T. Ahlgren and ASDEX Upgrade Team: Fusion tritons and<br />
plasma-facing components in a fusion reactor. 34 th European<br />
Physical Society Conference on Plasma Physics. Contributed<br />
Papers, (Eds.) P. Gasior, J. Wolowski. ECA 31 F. European<br />
Physical Society, Geneva, P-4.034 (<strong>2007</strong>).<br />
Jenko, F., C. Angioni, T. Dannert, F. Merz, A. G. Peeters and<br />
P. Xanthopoulos: Microturbulence in magnetic fusion devices:<br />
new insights from gyrokinetic simulation and theory. Fusion<br />
Energy 2006, International Atomic Energy Agency, Vienna,<br />
EX/8-5Ra (<strong>2007</strong>).<br />
Kallenbach, A., A. Chankin, D. Coster, T. Eich, J. Harhausen,<br />
A. Herrmann, B. Kurzan, H. W. Müller, E. Wolfrum, M. Wischmeier<br />
and ASDEX Upgrade Team: Divertor characterisation and data<br />
consistency in ASDEX Upgrade. 34 th European Physical<br />
Society Conference on Plasma Physics. Contributed Papers,<br />
(Eds.) P. Gasior, J. Wolowski. ECA 31 F. European Physical<br />
Society, Geneva, P-1.063 (<strong>2007</strong>).<br />
Kardaun, O., G. Becker, A. Kus, P. Lang, P. McCarthy, F. Ryter,<br />
A. Stäbler, J. Stober and Confinement Database Working<br />
Group: The tortuous route of confinement prediction near<br />
Operational Boundary Improvement of analysis based on<br />
ITERH.DB4/L.DB3 database. Fusion Energy 2006, International<br />
Atomic Energy Agency, Vienna, IT/P1-10 (<strong>2007</strong>).<br />
Kasparek, W., M. Petelin, D. Shchegolkov, V. Erckmann,<br />
B. Plaum, A. Bruschi and ECRH Groups at <strong>IPP</strong>, FZK and IPF:<br />
The electron cyclotron heating system for the stellarator W7-X:<br />
Status and recent achievements. Conference Digest of the 32 nd<br />
International Conference on Infrared and Millimeter Waves,<br />
and 15 th International Conference on Terahertz Electronics, IEEE<br />
Operation Center, Piscataway, NJ, CD-ROM, 939-940 (<strong>2007</strong>).<br />
Kasparek, W., M. Petelin, D. Shchegolkov, V. Erckmann,<br />
B. Plaum, A. Bruschi and ECRH Groups at <strong>IPP</strong>, FZK and IPF:<br />
FaDiS, a Fast Switch and Combiner for High-power Millimetre<br />
Wave Beams. Conference Digest of the 32 nd International<br />
Conference on Infrared and Millimeter Waves, and<br />
15 th International Conference on Terahertz Electronics, IEEE<br />
Operation Center, Piscataway, NJ, CD-ROM, 389-390 (<strong>2007</strong>).
Kirschner, A., V. Philipps, M. Balden, X. Bonnin, S. Brezinsek,<br />
J. P. Coad, D. Coster, S. K. Erents, H. G. Esser, W. Fundamenski,<br />
A. Huber, J. Likonen, H. Maier, G. F. Matthews, M. Mayer,<br />
R. A. Pitts, M. Rödig, M. J. Rubel, U. Samm, J. D. Strachan,<br />
M. Wischmeier and JET-EFDA Contributors: Material<br />
Erosion and Redeposition during the JET MkIIGB-SRP<br />
Divertor Campaign. Invited paper. Fusion Energy 2006,<br />
International Atomic Energy Agency, Vienna, EX/3-5 (<strong>2007</strong>).<br />
Konz, C., L. D. Horton, E. Strumberger, S. Günter, P. J. McCarthy,<br />
G. T. A. Huysmans, P. B. Snyder and ASDEX Upgrade Team:<br />
The Peeling-Ballooning Model Revisited. 34 th European<br />
Physical Society Conference on Plasma Physics. Contributed<br />
Papers, (Eds.) P. Gasior, J. Wolowski. ECA 31 F. European<br />
Physical Society, Geneva, P-4.067 (<strong>2007</strong>).<br />
Krychowiak, M., P. Mertens, B. Schweer, S. Brezinsek, R. König,<br />
O. Schmitz, M. Brix, T. Klinger and U. Samm: LIF measurements<br />
on an atomic helium beam in the edge of a fusion plasma.<br />
34 th European Physical Society Conference on Plasma Physics.<br />
Contributed Papers, (Eds.) P. Gasior, J. Wolowski. ECA 31 F.<br />
European Physical Society, Geneva, P-2.142 (<strong>2007</strong>).<br />
Kukushkin, A. S., H. D. Pacher, V. Kotov, D. Reiter, D. Coster,<br />
G. W. Pacher and H. P. Zehrfeld: Optimisation of the Shape of the<br />
ITER Divertor dome. 34 th European Physical Society Conference<br />
on Plasma Physics. Contributed Papers, (Eds.) P. Gasior, J. Wolowski.<br />
ECA 31 F. European Physical Society, Geneva, P-1.061 (<strong>2007</strong>).<br />
Kurzan, B., M. Gemisic-Adamov, L. D. Horton, H. Meister,<br />
H. Murmann, J. Neuhauser, W. Suttrop and ASDEX Upgrade Team:<br />
Analysis of large and small scale flucuations in the plasma edge<br />
of ASDEX Upgrade. 34 th European Physical Society Conference<br />
on Plasma Physics. Contributed Papers, (Eds.) P. Gasior, J. Wolowski.<br />
ECA 31 F. European Physical Society, Geneva, P-1.031 (<strong>2007</strong>).<br />
Lang, P. T., B. Alper, R. Buttery, K. Gal, J. Hobirk, J. Neuhauser,<br />
M. Stamp and JET EFDA Contributors: ELM triggering by<br />
local pellet perturbations at JET. 34 th European Physical<br />
Society Conference on Plasma Physics. Contributed Papers,<br />
(Eds.) P. Gasior, J. Wolowski. ECA 31 F. European Physical<br />
Society, Geneva, P-5.132 (<strong>2007</strong>).<br />
Lederer, H., R. Hatzky, R. Tisma, A. Bottino and F. Jenko:<br />
Hyperscaling of Plasma Turbulence Simulations in DEISA.<br />
Proceedings of the HPDC <strong>2007</strong> Conference & Co-Located<br />
Workshops, CLADE ’07. ACM, New York, NY, p. 19 ff. (<strong>2007</strong>).<br />
Lipschultz, B., N. Asakura, X. Bonnin, D. Coster, G. Counsell,<br />
R. Doerner, R. Dux, G. Federici, M. Fenstermacher, W. Fundamenski,<br />
P. Ghendrih, A. Herrmann, J. Hu, A. Kallenbach, S. Krasheninnikov,<br />
K. Krieger, G. Kirnev, A. Kreter, A. Kukushkin, V. Kurnaev,<br />
B. LaBombard, J. Li, S. Lisgo, A. Loarte, T. Nakano, R. Neu,<br />
Publications<br />
142<br />
N. Ohno, H. Pacher, J. Paley, Y. Pan, G. Pautasso, V. Philipps,<br />
V. Riccardo, V. Rohde, J. Roth, D. Rudakov, P. Stangeby,<br />
S. Takamura, T. Tanabe, E. Tsitrone, D. Whyte, Y. Yang and S. Zhu:<br />
Plasma-surface interaction, scrape-off layer and divertor physics:<br />
Implications for ITER. Invited paper. Fusion Energy 2006,<br />
International Atomic Energy Agency, Vienna, IT/1-4 (<strong>2007</strong>).<br />
Loarer, T., C. Brosset, J. Bucalossi, P. Coad, G. Esser, J. Hogan,<br />
J. Likonen, M. Mayer, P. Morgan, V. Philipps, V. Rohde, J. Roth,<br />
M. Rubel, E. Tsitrone and JET EFDA Contributors: Gas Balance<br />
and Fuel Retention in Fusion Devices. Fusion Energy 2006,<br />
International Atomic Energy Agency, Vienna, EX/3-6 (<strong>2007</strong>).<br />
Lunt, T., G. Fußmann and O. Waldmann: The ion velocity<br />
distribution in front of a neutralizing target. 34 th European<br />
Physical Society Conference on Plasma Physics. Contributed<br />
Papers, (Eds.) P. Gasior, J. Wolowski. ECA 31 F. European<br />
Physical Society, Geneva, P-1.043 (<strong>2007</strong>).<br />
Maggi, C. F., R. J. Groebner, N. Oyama, R. Sartori, L. D. Horton,<br />
A. C. C. Sips, W. Suttrop, ASDEX Upgrade Team, T. Leonard,<br />
T. C. Luce, M. R. Wade, DIIII-D-Team, Y. Kamada, H. Urano,<br />
JT-60U Team, Y. Andrew, C. Giroud, E. Joffrin, E. de la Luna<br />
and EFDA-JET Contributors: Characteristics of the H-mode<br />
pedestal improved confinement scenarios in ASDEX Upgrade,<br />
DIII-D, JET and JT-60U. Invited paper. Fusion Energy 2006,<br />
International Atomic Energy Agency, Vienna, IT/P1-6 (<strong>2007</strong>).<br />
Maier, H., T. Hirai, M. Rubel, R. Neu, P. Mertens, H. Greuner,<br />
C. Hopf, G. Matthews, O. Neubauer, G. Piazza, E. Gauthier,<br />
J. Likonen, R. Mitteau, G. Maddaluno, B. Riccardi, V. Philipps,<br />
C. Ruset, C. Lungu and JET EFDA Contributors: Tungsten<br />
and Beryllium Armour Development for the JET ITER-like<br />
Wall Project. Fusion Energy 2006, International Atomic<br />
Energy Agency, Vienna, IT/P2-4 (<strong>2007</strong>).<br />
Marushchenko, N. B., V. Erckmann, H. Maaßberg and Y. Turkin:<br />
Analysis of ECCD scenarios for different configurations of the<br />
W7-X Stellarator. 34 th European Physical Society Conference on<br />
Plasma Physics. Contributed Papers, (Eds.) P. Gasior, J. Wolowski.<br />
ECA 31 F. European Physical Society, Geneva, P-5.129 (<strong>2007</strong>).<br />
McCarthy, P. J., C. B. Forest, M. Foley, L. Giannone, O. Gruber,<br />
J. Hobirk, L. D. Horton, K. Lackner, P. Martin, M. Reich,<br />
W. Schneider, A. C. C. Sips and ASDEX Upgrade Team:<br />
Plasma geometry and current profile identification on ASDEX<br />
Upgrade using an integrated equilibrium generation and<br />
interpretation system. Fusion Energy 2006, International<br />
Atomic Energy Agency, Vienna, TH/P3-7 (<strong>2007</strong>).<br />
Medvedev, S. Yu, A. A. Ivanov, A. A. Martynov, Yu. Yu. Poshekhonov,<br />
S. H. Kim, J. B. Lister, Y. R. Martin, O. Sauter, L. Villiard and<br />
P. T. Lang: Edge stability and boundary shaping in tokamaks.
34 th European Physical Society Conference on Plasma Physics.<br />
Contributed Papers, (Eds.) P. Gasior, J. Wolowski. ECA 31 F.<br />
European Physical Society, Geneva, P-4.078 (<strong>2007</strong>).<br />
Merkel, P.: Feedback stabilization of resistive wall modes in<br />
the presence of multiply-connected wall structures. Fusion<br />
Energy 2006, International Atomic Energy Agency, Vienna,<br />
TH/P3-8 (<strong>2007</strong>).<br />
Müller, H. W., A. V. Chankin, B. Kurzan, M. Maraschek,<br />
J. Neuhauser, V. Rohde, A. Schmid, M. Tsalas, M. Wischmeier<br />
and ASDEX Upgrade Team: Parallel plasma flow and radial<br />
electric field in the scrape-off layer of ASDEX Upgrade.<br />
34 th European Physical Society Conference on Plasma<br />
Physics. Contributed Papers, (Eds.) P. Gasior, J. Wolowski.<br />
ECA 31 F. European Physical Society, Geneva, P-1.060 (<strong>2007</strong>).<br />
Na, Y.-S., J.-G. Kwak, J. Y. Kim, J.-M. Noterdaeme, B. H. Park<br />
and A. C. C. Sips: Modelling of ICRH-heated Ramp-up<br />
Phases at ASDEX Upgrade in KSTAR Experimental Conditions.<br />
34 th European Physical Society Conference on Plasma<br />
Physics. Contributed Papers, (Eds.) P. Gasior, J. Wolowski.<br />
ECA 31 F. European Physical Society, Geneva, P-5.147 (<strong>2007</strong>).<br />
Nemov, V. V., S. V. Kasilov, W. Kernbichler, B. Seiwald,<br />
Y. Suzuki and J. Geiger: Calculations of on effective ripple<br />
for a stellarator magnetic field computed by the HINT2<br />
code. 34 th European Physical Society Conference on Plasma<br />
Physics. Contributed Papers, (Eds.) P. Gasior, J. Wolowski.<br />
ECA 31 F. European Physical Society, Geneva, P-4.063 (<strong>2007</strong>).<br />
Neuhauser, J., V. Bobkov, A. Chankin, D. P. Coster, R. Dux,<br />
T. Eich, L. Fattorini, M. Garcia-Munoz, J. Harhausen, A. Herrmann,<br />
L. Horton, A. Kallenbach, S. Kalvin, A. Kirk, B. Koch,<br />
G. Kocsis, B. Kurzan, P. Lang, M. Maraschek, H. W. Müller,<br />
H. D. Murmann, R. Neu, M. Reich, V. Rohde, A. Schmid,<br />
W. Suttrop, M. Tsalas, M. Wischmeier, E. Wolfrum and ASDEX<br />
Upgrade Team: Structure and Dynamics of Spontaneous and<br />
Induced ELMs on ASDEX Upgrade. Fusion Energy 2006,<br />
International Atomic Energy Agency, Vienna, EX/P8-2 (<strong>2007</strong>).<br />
Nührenberg, C., S. R. Hudson and A. H. Boozer: Verification<br />
of the CAS3D-perturbed equilibrium code in the cylindrical<br />
limit. 34 th European Physical Society Conference on Plasma<br />
Physics. Contributed Papers, (Eds.) P. Gasior, J. Wolowski.<br />
ECA 31 F. European Physical Society, Geneva, P-4.065<br />
(<strong>2007</strong>).<br />
Ongena, J., J. Mailloux, Y. Baranov, L. Bertalot, C. D. Callis,<br />
G. Corrigan, A. Ekedahl, K. Erents, L.-G. Eriksson, M. Goniche,<br />
T. Hellsten, I. Jenkins, T. Johnson, D. L. Keeling, V. Kiptily,<br />
P. U. Lamalle, M. Laxaback, E. Lerche, M. J. Mantsinen,<br />
M.-L. Mayoral, J.-M. Noterdaeme, V. Parail, V. Petrizilka,<br />
Publications<br />
143<br />
S. Popovichev, A. Salmi, M. Santala, J. Spence, S. Sharapov,<br />
A. A. Tuccillo, D. Van Eester and EFDA-JET Contributors:<br />
Recent progress in JET on Heating and Current Drive studies<br />
in view of ITER. Fusion Energy 2006, International Atomic<br />
Energy Agency, Vienna, EX/P6-9 (<strong>2007</strong>).<br />
Pautasso, G., C. J. Fuchs, O. Gruber, A. Herrmann, K. Lackner,<br />
C. F. Maggi, M. Maraschek, T. Pütterich, E. Wolfrum and<br />
ASDEX Upgrade Team: Plasma shut-down with fast impurity<br />
puff on ASDEX Upgrade. Fusion Energy 2006, International<br />
Atomic Energy Agency, Vienna, EX/P8-7 (<strong>2007</strong>).<br />
Pautasso, G., J. C. Fuchs, O. Gruber, A. Gude, V. Igochine,<br />
K. Mark, V. Rohde, M. Beck, P. Cierpka, G. Prausner,<br />
C. Wittmann, ASDEX Upgrade Team, C. Linz, J. Simon,<br />
J. Weiser and V. Galazky: Recent results on disruptions mitigation<br />
with a new fast valve. 34 th European Physical Society<br />
Conference on Plasma Physics. Contributed Papers, (Eds.)<br />
P. Gasior, J. Wolowski. ECA 31 F. European Physical Society,<br />
Geneva, P-5.151 (<strong>2007</strong>).<br />
Pereverzev, G. V.: Asymptotic description of high frequency<br />
eigenmodes in tokamak. 34 th European Physical Society<br />
Conference on Plasma Physics. Contributed Papers, (Eds.)<br />
P. Gasior, J. Wolowski. ECA 31 F. European Physical Society,<br />
Geneva, P-5.061 (<strong>2007</strong>).<br />
Pereverzev, G. V., S. Günter, K. Lackner and E. Strumberger:<br />
Transport and stability study of a fusion power plant scenario.<br />
Fusion Energy 2006, International Atomic Energy Agency,<br />
Vienna, FT/P5-23 (<strong>2007</strong>).<br />
Piosczyk, B., G. Dammertz, A. Arnold, G. Gantenbein, S. Illy,<br />
J. Jin, O. Prinz, J. Flamm, T. Rzesnicki, M. Thumm, S. Alberti,<br />
T. Goodmann, J. P. Hogge, M. Q. Tran, V. Erckmann, H. Laqua,<br />
G. Michel, O. Dumbrajs, P. Benin, E. Giguet and C. Lievin:<br />
Development of High Power Gyrotrons for Fusion Applications<br />
at FZK. IEEE Pulsed Power and Plasma Science Conference<br />
(ICOPS <strong>2007</strong>). CD-ROM, Albuquerque, NM, 551 (<strong>2007</strong>).<br />
Piovesan, P., V. Igochine, P. Lauber, K. Sassenberg, A. Flaws,<br />
M. Garcia-Munoz, S. Günter, M. Maraschek, L. Marrelli,<br />
P. Martin, P. McCarty and AUG Team: TAE internal structure<br />
through high-resolution soft x-ray measurements in ASDEX<br />
Upgrade. 34 th European Physical Society Conference on Plasma<br />
Physics. Contributed Papers, (Eds.) P. Gasior, J. Wolowski.<br />
ECA 31 F. European Physical Society, Geneva, P-1.139 (<strong>2007</strong>).<br />
Preuss, R., A. Dinklage, A. Weller and W7-AS Team: Assessment<br />
of confinement scaling models for W7-AS high-ß data.<br />
34 th European Physical Society Conference on Plasma<br />
Physics. Contributed Papers, (Eds.) P. Gasior, J. Wolowski.<br />
ECA 31 F. European Physical Society, Geneva, P-2.054 (<strong>2007</strong>).
Preuss, R. and U. von Toussaint: Comparison of numerical<br />
methods for evidence calculation. Bayesian Inference and<br />
<strong>Max</strong>imum Entropy Methods in Science and Engineering:<br />
27 th International Workshop on Bayesian Inference and <strong>Max</strong>imum<br />
Entropy Methods in Science and Engineering. (Eds.)<br />
K. H. Knuth, A. Caticha, J. L. Center, A. Giffin, C. C. Rodriguez.<br />
AIP Conference Proceedings 954. American <strong>Institut</strong>e of<br />
Physics, Melville, NY, 221-228 (<strong>2007</strong>).<br />
Pütterich, T., R. Neu, R. Dux and ASDEX Upgrade Team:<br />
Spectroscopic Diagnostic of Tungsten in Fusion Plasmas.<br />
34 th European Physical Society Conference on Plasma Physics.<br />
Contributed Papers, (Eds.) P. Gasior, J. Wolowski. ECA 31 F.<br />
European Physical Society, Geneva, P-5.103 (<strong>2007</strong>).<br />
Rambadt, M., R. Breu, L. Clementi, T. Fieseler, A. Gieseler,<br />
W. Gürich, P. Malfetti, R. Menday, J. Reetz and A. Streit:<br />
DEISA and D-Grid: using UNICORE in production Grid<br />
infrastructures. German e-Science (GeS) Conference. <strong>Max</strong>-<br />
<strong>Planck</strong>-Digital Library, München (<strong>2007</strong>).<br />
http://www.ges<strong>2007</strong>.de<br />
Reetz, J., T. Soddemann, B. Heupers and J. Wolfrat: Accounting<br />
Facilities in the European Supercomputing Grid DEISA.<br />
German e-Science (GeS) Conference. <strong>Max</strong>-<strong>Planck</strong>-Digital<br />
Library, München (<strong>2007</strong>).<br />
http://www.ges<strong>2007</strong>.de<br />
Reich, M., M. Brix, V. Kiptily, S. D. Pinches, A. Werner and<br />
JET-EFDA Contributors: Particle loss signatures during<br />
sawtooth events at JET. 34 th European Physical Society<br />
Conference on Plasma Physics. Contributed Papers, (Eds.)<br />
P. Gasior, J. Wolowski. ECA 31 F. European Physical Society,<br />
Geneva, O-4.016 (<strong>2007</strong>).<br />
Reich, M., P. McCarthy, J. Hobirk and ASDEX Upgrade Team:<br />
Calibration methods for the MSE diagnostic at ASDEX<br />
Upgrade. 34 th European Physical Society Conference on Plasma<br />
Physics. Contributed Papers, (Eds.) P. Gasior, J. Wolowski.<br />
ECA 31 F. European Physical Society, Geneva, P-2.127<br />
(<strong>2007</strong>).<br />
Reiman, A., M. C. Zarnstorff, D. Monticello, J. Krommes,<br />
A. Weller, J. Geiger and W7-AS Team: Localized Breaking<br />
of Flux Surfaces and the Equilibrium β Limit in the W7AS<br />
Stellarator. Fusion Energy 2006, International Atomic Energy<br />
Agency, Vienna, TH/P7-3 (<strong>2007</strong>).<br />
Ribeiro, T. T., B. Scott and F. Serra: Self consistent MHD<br />
equilibrium in turbulence simulations. 34 th European Physical<br />
Society Conference on Plasma Physics. Contributed Papers,<br />
(Eds.) P. Gasior, J. Wolowski. ECA 31 F. European Physical<br />
Society, Geneva, P-4.055 (<strong>2007</strong>).<br />
Publications<br />
144<br />
Rohde, V., V. Mertens, T. Loarer and ASDEX Upgrade Team:<br />
Gas balance in high density discharges at ASDEX Upgrade.<br />
34 th European Physical Society Conference on Plasma<br />
Physics. Contributed Papers, (Eds.) P. Gasior, J. Wolowski.<br />
ECA 31 F. European Physical Society, Geneva, P-2.030 (<strong>2007</strong>).<br />
Ryter, F., G. Tardini, L. D. Horton, W. Schneider, W. Suttrop,<br />
R. Fischer, N. Hicks, P. J. McCarthy, A. Stäbler, J. Stober,<br />
E. Wolfrum and ASDEX Upgrade Team: Experimental determination<br />
of the NBI power deposition and consequences for NBI<br />
current drive. 34 th European Physical Society Conference on<br />
Plasma Physics. Contributed Papers, (Eds.) P. Gasior, J. Wolowski.<br />
ECA 31 F. European Physical Society, Geneva, P-1.140 (<strong>2007</strong>).<br />
Rzesnicki, T., B. Piosczyk, G. Dammertz, G. Gantenbein,<br />
M. Thumm and G. Michel: 170 GHz, 2 MW coaxial cavity<br />
gyrotron – investigation of the parasitic oscillations and efficiency<br />
of the RF-output system. Proceedings of the 8 th IEEE<br />
International Vacuum Electronics Conference. IEEE Operation<br />
Center, Piscataway, NJ, 45-46 (<strong>2007</strong>).<br />
Schirmer, J., C. Maggi, H. Zohm, R. Dux, A. Flaws, M. Maraschek,<br />
A. Peeters, K. Sassenberg, A. Scarabosio, L. Urso and ASDEX<br />
Upgrade Team: Rotation frequencies of MHD modes in ASDEX<br />
Upgrade. 34 th European Physical Society Conference on Plasma<br />
Physics. Contributed Papers, (Eds.) P. Gasior, J. Wolowski.<br />
ECA 31 F. European Physical Society, Geneva, P-1.133 (<strong>2007</strong>).<br />
Schmid, A., A. Hermann, A. Kirk, J. Neuhauser, S. Günter,<br />
H. W. Müller, M. Maraschek, V. Rohde and ASDEX Upgrade Team:<br />
Characterization of Type-I ELM Induced Filaments in ASDEX<br />
Upgrade. 34 th European Physical Society Conference on Plasma<br />
Physics. Contributed Papers, (Eds.) P. Gasior, J. Wolowski.<br />
ECA 31 F. European Physical Society, Geneva, P-1.026 (<strong>2007</strong>).<br />
Schmid, K., T. Schwarz-Selinger, W. Jacob, R. Dux and ASDEX<br />
Upgrade Team: The implications of high-Z first wall materials<br />
on noble gas wall recycling. Fusion Energy 2006, International<br />
Atomic Energy Agency, Vienna, EX/3-3Rb (<strong>2007</strong>).<br />
Schneider, R.: Plasma-wall interaction: how atomic processes<br />
influence the performance of fusion plasmas. Atomic Processes<br />
in Plasmas: The 15 th International Conference on Atomic Processes<br />
in Plasmas. (Eds.) J. D. Gillaspy, J. J. Curry, W. L. Wiese.<br />
AIP Conference Proceedings 926. American <strong>Institut</strong>e of<br />
Physics, Melville, NY, 45-55 (<strong>2007</strong>).<br />
Schrittwieser, R., A. Kendl, S. Konzett, C. Ionita, F. Mehlmann,<br />
P. Balan, V. Naulin, J. J. Rasmussen, A. H. Nielsen, O. E. Garcia,<br />
H. W. Müller, A. Herrmann, V. Rohde, M. Maraschek and<br />
ASDEX Upgrade Team: Experimental and numerical characterisation<br />
of fluctuations in the SOL of ASDEX Upgrade<br />
during L-mode and ELMy H-mode. 34 th European Physical
Society Conference on Plasma Physics. Contributed Papers,<br />
(Eds.) P. Gasior, J. Wolowski. ECA 31 F. European Physical<br />
Society, Geneva, P-1.125 (<strong>2007</strong>).<br />
Schustereder, W., A. Herrmann, K. Krieger, V. Rohde and<br />
ASDEX Upgrade Team: Impurity fluxes in the scrape-off<br />
layer of ASDEX Upgrade in the full tungsten wall configuration.<br />
34 th European Physical Society Conference on Plasma<br />
Physics. Contributed Papers, (Eds.) P. Gasior, J. Wolowski.<br />
ECA 31 F. European Physical Society, Geneva, P-2.034 (<strong>2007</strong>).<br />
Scott, B., A. Kendl, D. Reiser, T. Ribeiro and D. Strinzi:<br />
Studies of the tokamak edge with self consistent turbulence,<br />
equilibrium, and flows. Fusion Energy 2006, International<br />
Atomic Energy Agency, Vienna, TH/1-1 (<strong>2007</strong>).<br />
Sips, A. C. C., C. Forest, O. Gruber, P. J. McCarthy, O. Kardaun,<br />
V. Mertens, A. Peeters, G. V. Pereverzev, A. Stäbler, J. Stober,<br />
G. Tardini and ASDEX Upgrade Team: The performance of<br />
improved H-modes at ASDEX Upgrade and projection to<br />
ITER. Fusion Energy 2006, International Atomic Energy<br />
Agency, Vienna, EX/1-1 (<strong>2007</strong>).<br />
Stober, J., V. Bobkov, C. Forest, O. Gruber, J. Hobirk, L. D. Horton,<br />
C.F. Maggi, M. Maraschek, P. Martin, V. Mertens, Y.-S. Na,<br />
M. Reich, A. C. C. Sips, A. Stäbler, G. Tardini, H. Zohm,<br />
P. McCarthy and ASDEX Upgrade Team: Physics studies of<br />
the improved H-mode scenario in ASDEX Upgrade. Fusion<br />
Energy 2006, International Atomic Energy Agency, Vienna,<br />
EX/P1-7 (<strong>2007</strong>).<br />
Stober, J., A. Gude, F. Leuterer, A. Manini, R. Neu, T. Pütterich,<br />
A. C. C. Sips, D. Wagner, H. Zohm and ASDEX Upgrade Team:<br />
First experiments with the extended ECRH system on ASDEX<br />
Upgrade. 34 th European Physical Society Conference on Plasma<br />
Physics. Contributed Papers, (Eds.) P. Gasior, J. Wolowski.<br />
ECA 31 F. European Physical Society, Geneva, P-5.138 (<strong>2007</strong>).<br />
Suttrop, W., T. Bertoncelli, V. Bobkov, O. Gruber, A. Herrmann,<br />
P. Merkel, M. Rott, M. Sempf, U. Seidel, B. Streibel, E. Strumberger,<br />
T. Vierle, D. Yadikin, Q. Yu and ASDEX Upgrade Team: Active<br />
in-vessel coils and a conducting wall for MHD control in<br />
ASDEX Upgrade. 34 th European Physical Society Conference<br />
on Plasma Physics. Contributed Papers, (Eds.) P. Gasior,<br />
J. Wolowski. ECA 31 F. European Physical Society, Geneva,<br />
P-5.119 (<strong>2007</strong>).<br />
Suttrop, W., L. D. Horton, C. Konz, B. Kurzan, C. F. Maggi,<br />
H. Meister, J. Neuhauser, A. C. C. Sips, U. Urano, E. Wolfrum<br />
and ASDEX Upgrade Team: Studies of the edge pedestal and<br />
behaviour of edge localised modes in improved H-mode and<br />
small-ELM regimes in ASDEX Upgrade. Fusion Energy 2006,<br />
International Atomic Energy Agency, Vienna, EX/P8-5 (<strong>2007</strong>).<br />
Publications<br />
145<br />
Szepesi, T., S. Kalvin, G. Kocsis, P. T. Lang and ASDEX Upgrade<br />
Team: Radial acceleration of solid hydrogen pellets in hot<br />
tokamak plasmas. 34 th European Physical Society Conference<br />
on Plasma Physics. Contributed Papers, (Eds.) P. Gasior,<br />
J. Wolowski. ECA 31 F. European Physical Society, Geneva,<br />
P-4.037 (<strong>2007</strong>).<br />
Tardini, G., L. D. Horton, O. Kardaun, C. F. Maggi, A. G. Peeters,<br />
G. V. Pereverzev, A. C. C. Sips, J. Stober and ASDEX Upgrade<br />
Team: Extrapolation of ASDEX Upgrade H-mode discharges<br />
to ITER. 34 th European Physical Society Conference on Plasma<br />
Physics. Contributed Papers, (Eds.) P. Gasior, J. Wolowski.<br />
ECA 31 F. European Physical Society, Geneva, P-1.090 (<strong>2007</strong>).<br />
Toi, K., F. Watanabe, S. Ohdachi, K. Narihara, T. Morisaki,<br />
S. Sakakibara, X. Gao, M. Goto, K. Ida, M. Kobayashi, S. Masuzaki,<br />
J. Miyazawa, S. Morita, K. Tanaka, T. Tokuzawa, K. W. Watanabe,<br />
A. Weller, L. Yan, M. Yoshinuma, K. Kawahata, A. Komori and<br />
LHD Experimental Group: Characteristic Features of Edge<br />
Transport Barrier Formed in Helical Divertor Configuration<br />
of the Large Helical Device. Fusion Energy 2006, International<br />
Atomic Energy Agency, Vienna, EX/P1-13 (<strong>2007</strong>).<br />
Tröster, C., G. D. Conway, W. Suttrop, J. Schirmer, H. Zohm<br />
and ASDEX Upgrade Team: Density fluctuation measurements<br />
with fast-sweep X-mode reflectometry. 8 th International<br />
Reflectometry Workshop (IRW8), Open Access, 80-84 (<strong>2007</strong>).<br />
http://plasma.ioffe.ru/irw8/proceedings.html<br />
Waldmann, O., G. Fußmann and W. Bohmeyer: Ion mass<br />
spectrometry in a magnetized plasma. 34 th European Physical<br />
Society Conference on Plasma Physics. Contributed Papers,<br />
(Eds.) P. Gasior, J. Wolowski. ECA 31 F. European Physical<br />
Society, Geneva, P-5.108 (<strong>2007</strong>).<br />
Weisen, H., C. Angioni, A. Zabolotsky, M. Maslov, M. Beurskens,<br />
C. Fuchs, L. Garzotti, C. Giroud, B. Kurzan, P. Mantica, D. Mazon,<br />
M. E. Puiatti, K.-D. Zastrow, JET-EFDA Work Programme,<br />
ASDEX Upgrade Team and TCV Team: Peaked density profiles<br />
in low collisionality H-modes in JET, ASDEX Upgrade<br />
and TCV. Fusion Energy 2006, International Atomic Energy<br />
Agency, Vienna, EX/8-4 (<strong>2007</strong>).<br />
Weller, A., A. Werner, J. Geiger, C. Nührenberg, H. Thomsen<br />
and W7-AS Team: Multi-Harmonic Modes in W7-AS High-Beta<br />
Configurations. 34 th European Physical Society Conference on<br />
Plasma Physics. Contributed Papers, (Eds.) P. Gasior, J. Wolowski.<br />
ECA 31 F. European Physical Society, Geneva, P-1.112 (<strong>2007</strong>).<br />
Werner, A., A. Dinklage, G. Kühner, H. Maaßberg, J. Schacht,<br />
J. Svensson, U. von Toussaint and Y. Turkin: Integrated Software<br />
Development for Wendelstein 7-X. Fusion Energy 2006,<br />
International Atomic Energy Agency, Vienna, FT/P7-6 (<strong>2007</strong>).
Wischmeier, M., D. Coster, A. Chankin, C. Fuchs, M. Groth,<br />
J. Harhausern, A. Kallenbach, H. W. Müller, M. Tsalas and<br />
ASDEX Upgrade Team: Simulating divertor detachment of<br />
ohmic discharges in ASDEX Upgrade using SOLPS: the<br />
role of Carbon. 34 th European Physical Society Conference<br />
on Plasma Physics. Contributed Papers, (Eds.) P. Gasior,<br />
J. Wolowski. ECA 31 F. European Physical Society, Geneva,<br />
P-1.040 (<strong>2007</strong>).<br />
Wittenburg, P., D. Broeder, M. Kemps-Snijders, A. Dimitriadis<br />
and T. Soddemann: A Federation of Language Archives<br />
Enabling Future eHumanitaies Scenarios. German e-Science<br />
(GeS) Conference. <strong>Max</strong> <strong>Planck</strong> Digital Library, München<br />
(<strong>2007</strong>).<br />
http://www.ges<strong>2007</strong>.de<br />
Wolfrum, E., D. Coster, C. Konz, M. Reich and ASDEX Upgrade<br />
Team: Edge ion temperature gradients in H-mode discharges.<br />
34 th European Physical Society Conference on Plasma Physics.<br />
Contributed Papers, (Eds.) P. Gasior, J. Wolowski. ECA 31 F.<br />
European Physical Society, Geneva, P-2.039 (<strong>2007</strong>).<br />
Wünderlich, D., R. Gutser, U. Fantz, M. Berger, S. Christ-<br />
Koch, H. D. Falter, P. Franzen, M. Fröschle, B. Heinemann,<br />
W. Kraus, C. Martens, P. McNeely, R. Riedl and E. Speth:<br />
Modeling of a Negative Ion RF Source for ITER NBI. 34 th<br />
European Physical Society Conference on Plasma Physics.<br />
Contributed Papers, (Eds.) P. Gasior, J. Wolowski. ECA 31 F.<br />
European Physical Society, Geneva, P-1.149 (<strong>2007</strong>).<br />
Yokoyama, M., H. Maaßberg, K. Ida, C. Beidler, F. Castejon,<br />
T. Estrada, A. Fujisawa, T. Minami, T. Shimozuma, Y. Takeiri,<br />
V. Tribaldos, A. Dinklage, S. Murakami and H. Yamada:<br />
Core Electron-Root Confinement (CERC) in Helical Plasmas.<br />
Fusion Energy 2006, International Atomic Energy Agency,<br />
Vienna, EX/5-3 (<strong>2007</strong>).<br />
Yu, Q.: Theoretical Studies on the Physics of Magnetic Islands.<br />
Fusion Energy 2006, International Atomic Energy Agency,<br />
Vienna, TH/P3-13 (<strong>2007</strong>).<br />
Zhang, D., L. Giannone, B. Klein and W7-X Team: The<br />
Bolometry Concept for the W7-X Stellarator. 34 th European<br />
Physical Society Conference on Plasma Physics. Contributed<br />
Papers, (Eds.) P. Gasior, J. Wolowski. ECA 31 F. European<br />
Physical Society, Geneva, P-5.111 (<strong>2007</strong>).<br />
Zohm, H., S. Cirant, G. Gantenbein, S. Günter, F. Leuterer,<br />
A. Manini, M. Maraschek, L. Urso, Q. Yu and ASDEX<br />
Upgrade Team: Control of MHD instabilities by ECCD:<br />
ASDEX Upgrade results and implications for ITER. Fusion<br />
Energy 2006, International Atomic Energy Agency, Vienna,<br />
EX/4-1Rb (<strong>2007</strong>).<br />
Publications<br />
146<br />
Thesis<br />
Boosch, S.: Optimierung der Montageplanung <strong>für</strong> die regulären<br />
Stutzen des Wendelstein 7-X, Erstellung eines Quality<br />
Assurance and Assembly Plans (QAAP’s). Fachhochschule<br />
Stralsund (<strong>2007</strong>).<br />
Botzenhart, F.: Optimale Nutzung von Solarenergie unter<br />
thermodynamischen Aspekten und wirtschaftlichem Kalkül.<br />
Universität Augsburg (<strong>2007</strong>).<br />
Cwiklinski, A.: Wechselwirkung zwischen Stickstoff und<br />
Kohlenstoff in magnetisierten Plasmen. Freie Universität<br />
und Humboldt-Universität Berlin (<strong>2007</strong>).<br />
Hertkorn, T.: Nichtlineare Triaden Wechselwirkungen in<br />
zweidimensionaler Turbulenz. Universität Bayreuth<br />
(<strong>2007</strong>).<br />
Köppl, S.: Charakterisierung und Hochtemperaturoxidation<br />
von W-Legierungen. Technische Universität München<br />
(<strong>2007</strong>).<br />
Krüger, M.: Konzept zur Nutzung von Biogas zur Wärmeund<br />
Elektroenergieerzeugung in der Hansestadt Greifswald.<br />
Hochschule Wismar (<strong>2007</strong>).<br />
Kuckahn, A.: Untersuchung der Übertragungsstrecke von<br />
den Messsensoren unter den extremen Bedingungen eines<br />
Kernfusionsexperiments. Fachhochschule Coburg (<strong>2007</strong>).<br />
Langer, B.: Bestimmung des radialen elektrischen Feldes<br />
am Plasmarand durch linienintegrierte Messungen an He+.<br />
Technische Universität München (<strong>2007</strong>).<br />
Leonard, V.: Scada System for the Stellarator W7-X.<br />
Technical University Gdánsk (<strong>2007</strong>).<br />
Mechel, J.: Untersuchung der Biegebelastbarkeit von Aluminiumschweißnähten<br />
am Mantel eines Supraleiters. Fachhochschule<br />
Stralsund (<strong>2007</strong>).<br />
Schmuck, S.: Designstudien <strong>für</strong> die Thomson-Streuung von<br />
Wendelstein 7-X. Ernst-Moritz-Arndt-Universität Greifswald<br />
(<strong>2007</strong>).<br />
Seidel, R.: Röntgenspektroskopie hochgeladener Wolfram-<br />
Ionen. Humboldt-Universität Berlin (<strong>2007</strong>).<br />
Versteegh, A.: Analysis of a Longliving Atmospheric Plasmoid.<br />
Technische Universität Eindhoven und Humboldt-Universität<br />
Berlin (<strong>2007</strong>).
Wigger, C.: Entwicklung eines Codes zum Test von Gleichgewichten<br />
gegen axisymmetrische Instabilitäten im Tokamak.<br />
Ludwig-<strong>Max</strong>imilians-Universität München (<strong>2007</strong>).<br />
Zimmerer, H.: Evaluation of sequence comparison methods<br />
for metagenomics. Eberhard-Karls-Universität Tübingen<br />
(<strong>2007</strong>).<br />
PhD-Thesis<br />
Allen, F. I.: Electron Capture by Highly Charged Ions from<br />
Surfaces and Gases. Humboldt-Universität Berlin (<strong>2007</strong>).<br />
Barth, S.: Untersuchung des Interatomaren Coulomb-Zerfalls<br />
in schwach gebundenen Systemen. Technische Universität<br />
Berlin (<strong>2007</strong>).<br />
Bizyukov, I.: Sputtering and surface modification of tungsten<br />
layers by bombardment with deuterium and carbon ion beams.<br />
V. N. Karazin Kharkiv National University, Kharkiv (<strong>2007</strong>).<br />
Dreier, H.: Bayesian Experimental Design – Applications in<br />
Nuclear Fusion. Ernst-Moritz-Arndt-Universität Greifswald<br />
(<strong>2007</strong>).<br />
Köck, T.: Herstellung und Charakterisierung eines SiC/Cu-<br />
Metall-Matrix-Verbundwerkstoffes mit angepasster Faser/<br />
Matrix-Grenzfläche. Technische Universität München (<strong>2007</strong>).<br />
Krychowiak, M.: Laser-induced fluorescence of atomic helium<br />
beams in a fusion edge plasma. Ernst-Moritz-Arndt-Universität<br />
Greifswald (<strong>2007</strong>).<br />
Skandera, D.: Statistical Properties and Structure of Turbulent<br />
Convection. Technische Universität München (<strong>2007</strong>).<br />
Ulrich, V.: Untersuchung von Autoionisationsprozessen in<br />
kleinen Molekülen und Clustern mittels hochauflösender<br />
Elektronenkoinzidenzspektroskopie. Technische Universität<br />
Berlin (<strong>2007</strong>).<br />
Windisch, T.: Intermittent events and structure propagation in<br />
plasma turbulence. Ernst-Moritz-Arndt-Universität Greifswald<br />
(<strong>2007</strong>).<br />
Habilitation<br />
Naujoks, D.: Plasma-Surface Interaction in Controlled Fusion.<br />
Humboldt-Universität Berlin (<strong>2007</strong>).<br />
Publications<br />
147<br />
Patents<br />
Brockmann, R.: Doppellagentechnik. Erfindungsmeldung:<br />
1.02.<strong>2007</strong>. Inanspruchnahme als Know-how: 16.05.<strong>2007</strong>.<br />
Brockmann, R.: Leckortung innerhalb einer begehbaren<br />
Prüfkammer. Erfindungsmeldung: 19.01.<strong>2007</strong>. Inanspruchnahme<br />
als Know-how: 16.05.<strong>2007</strong>.<br />
Brockmann, R.: Verfahren und Vorrichtung zur Leckprüfung.<br />
Keine Auslandsanmeldungen: 26.02.<strong>2007</strong>.<br />
Brockmann, R.: Verfahren zur Vermeidung von Porenbildung<br />
beim Schweißen von Werkstoffen. Erfindungsmeldung:<br />
10.10.<strong>2007</strong>. Inanspruchnahme als Know-how: 18.12.<strong>2007</strong>.<br />
Erckmann, V., G. Dammertz and M. Schmid: Method and<br />
Apparatus for collector sweeping control of an electron<br />
beam. Erfindungsmeldung vom 12.03.<strong>2007</strong>. Gemeinsame<br />
Anmeldung mit FZK: 5.05.<strong>2007</strong>.<br />
Schauer, F.: Stromzuführungseinrichtung. Einleitung der<br />
nationalen und regionalen Phasen der PCT-Anmeldung:<br />
1.06.<strong>2007</strong>.<br />
Schauer, F. and M. Nagel: Thermischer Schild. Freigabe der<br />
Anmeldung: 13.03.<strong>2007</strong>.<br />
Scholz, T.: Verbesserte Potentialtrenner. Erfindungsmeldung:<br />
13.06.<strong>2007</strong>. Freigabe der Erfindung: 26.07.<strong>2007</strong>.<br />
Sihler, C.: Verfahren und Dämpfungsvorrichtung zur Dämpfung<br />
einer Torsionsschwingung in einem rotierenden Antriebsstrang.<br />
Erweiterung der Anmeldung auf Hongkong:<br />
19.01.<strong>2007</strong>.<br />
Wanner, M.: Sicherheitseinrichtung mit geringem Ansprechdruck<br />
<strong>für</strong> Vakuumbehälter mit hohen Dichtheitsanforderungen.<br />
Keine Auslandsanmeldungen: 31.07.<strong>2007</strong>.
Laboratory <strong>Report</strong>s<br />
Internal <strong>IPP</strong> <strong>Report</strong>s<br />
<strong>IPP</strong> 4/286<br />
Gutser, R., D. Wünderlich, U. Fantz and P. Franzen: Rechnungen<br />
zur Extraktion negativer Wasserstoffionen aus einem<br />
HF-Plasma. 145 p. (<strong>2007</strong>).<br />
<strong>IPP</strong>5/119<br />
Dimova, K. and R. Meyer-Spasche: On a Moving Boundary<br />
Model of Anomalous Heat Transport in a Tokamak Plasma.<br />
18 p. (<strong>2007</strong>).<br />
<strong>IPP</strong> 10/33<br />
Berger, M. and U. Fantz: Cavity-Ringdown-Spektroskopie<br />
an Wasserstoff-Niederdruckplasmen. 93 p. (<strong>2007</strong>).<br />
<strong>IPP</strong> 12/3<br />
Eckstein, W., R. Dohmen, A. Mutzke and R. Schneider:<br />
SDTrimSP: A Monte Carlo Code for Calculating Collision<br />
Phenomena in Randomized Targets. 40 p. (<strong>2007</strong>).<br />
<strong>IPP</strong> 13/6<br />
Krychowiak, M.: Laser-induced fluorescence of atomic helium<br />
beams in a fusion edge plasma. 177 p. (<strong>2007</strong>).<br />
<strong>IPP</strong> 13/7<br />
Schmuck, S.: Designstudien <strong>für</strong> die Thomson-Streuung von<br />
Wendelstein 7-X. 92 p. (<strong>2007</strong>).<br />
<strong>IPP</strong> 13/8<br />
Dreier, H.: Bayesian Experimental Design – Applications in<br />
Nuclear Fusion. 143 p. (<strong>2007</strong>).<br />
<strong>IPP</strong> 16/12<br />
Barth, S.: Untersuchung des Interatomaren Coulomb-Zerfalls<br />
in schwach gebundenen Systemen. 133 p. (<strong>2007</strong>).<br />
<strong>IPP</strong> 16/13<br />
Tosato, G. C.: Lehren aus globalen Energieszenarien; Global<br />
long-term energy scenarios: lessons learnt. 83 p. (<strong>2007</strong>).<br />
<strong>IPP</strong> 16/14<br />
Hamacher, T., S. Winkelmüller and J. Kuckelkorn: Energiekonzept<br />
<strong>für</strong> das Konversionsgelände Sheridan-Kaserne in<br />
Augsburg. 101 p. (<strong>2007</strong>).<br />
<strong>IPP</strong> 16/16<br />
Krüger, M.: Konzept zur Nutzung von Biogas zur Wärmeund<br />
Elektroenergieerzeugung in der Hansestadt Greifswald.<br />
Hochschule Wismar. 134 p. (<strong>2007</strong>).<br />
Publications<br />
148<br />
<strong>IPP</strong> 16/17<br />
Botzenhart, F.: Optimale Nutzung von Solarenergie unter<br />
thermodynamischen Aspekten und wirtschaftlichem Kalkül.<br />
221 p. (<strong>2007</strong>).<br />
External <strong>Report</strong>s<br />
Nuorkivi, A., N. Killström, P. Saarnia, E. Tähti, J. Markovitch,<br />
G. Naumov and T. Hamacher: Energy. Future. Responsibility.<br />
– Promoting Energy Saving and Corporate Social<br />
Responsibility in the Baltic Sea Region. In: Publications of the<br />
Uusimaa Regional Council C 59. Uusimaa Regional Council,<br />
Helsinki Region, 63 p. (<strong>2007</strong>).<br />
NIFS-874<br />
Preuss, R., H. Yamada, M. Osakabe, S. Sakakibara, K.<br />
Tanaka, K.Y. Watanabe and A. Dinklage: Determination of<br />
uncertainties in the machine variables of LHD and CHS for<br />
confinement time scaling. National <strong>Institut</strong>e of Fusion<br />
Science (NIFS), Oroshi-cho, Toki-shi, Gifu-ken, 8 p. (<strong>2007</strong>).
Adelhelm, C., M. Balden, E. Cochran and S. Denis: Protection<br />
of carbon films against chemical erosion by doping with<br />
transition metals. (E-MRS Spring Meeting, Symposium Q:<br />
Protective Coatings and Thin Films, <strong>2007</strong>-05-28 to <strong>2007</strong>-06-01,<br />
Strasbourg).<br />
Adelhelm, C., M. Balden, M. Rinke and M. Stüber: Influence<br />
of metal-doping and annealing on the structure of amorphous<br />
carbon films. (17 th International Vacuum Congress (IVC-17),<br />
13 th International Conference on Surface Science (ICSS-13),<br />
International Conference on Nano Science and Technology<br />
(ICN+T <strong>2007</strong>), <strong>2007</strong>-07-02 to <strong>2007</strong>-07-06, Stockholm).<br />
Adelhelm, C., M. Balden, P. Starke, A. Centeno, C. Blanco,<br />
I. Lopez Galilea and C. Garcia-Rosales: Deuterium ion beam<br />
and plasma exposure experiments of metal-doped carbon<br />
materials relevant for fusion applications. (European Congress<br />
and Exhibition on Advanced Materials and Processes<br />
(EUROMAT <strong>2007</strong>), <strong>2007</strong>-09-10 to <strong>2007</strong>-09-13, Nürnberg).<br />
Allmaier, K., C. D. Beidler, M. Yu. Isaev, S. V. Kasilov,<br />
W. Kernbichler, H. Maaßberg, S. Murakami, V. V. Nemov,<br />
D. A. Spong and V. Tribaldos: ICNTS – Benchmarking of Bootstrap<br />
Current Coefficients. (Joint Conference of 17 th International<br />
Toki Conference on Physics of Flows and Turbulence<br />
in Plasmas and 16 th International Stellarator/Heliotron<br />
Workshop, <strong>2007</strong>-10-15 to <strong>2007</strong>-10-19, Ceratopia Toki, Gifu).<br />
Angelino, P., V. Grandgirard, Y. Sarazin, G. Dif-Pradalier,<br />
S. Jolliet, A. Bottino, X. Garbet, P. Ghendrih, B. McMillan,<br />
T. M. Tran and L. Villard: Benchmark of a semi-Lagrangian<br />
and a Lagrangian code for gyrokinetic simulations. (12 th US-<br />
EU Transport Taskforce Workshop (TTF-12), <strong>2007</strong>-04-17 to<br />
<strong>2007</strong>-04-20, San Diego, CA).<br />
Angelino, P., V. Grandgirard, Y. Sarazin, G. Dif-Pradalier,<br />
S. Jolliet, A. Bottino, X. Garbet, P. Ghendrih, B. McMillan,<br />
T.M. Tran and L. Villard: Effects of plasma elongation on Geodesic<br />
Acoustic Modes. (International Sherwood Fusion Theory<br />
Conference, <strong>2007</strong>-04-23 to <strong>2007</strong>-04-25, Annapolis, MD).<br />
Antar, G. Y., E. Wolfrum, M. Tsala, D. P. Coster, C. Konz,<br />
H. W. Müller, J. Neuhauser, V. Rohde, B. Scott, M. Wischmeier<br />
and ASDEX Upgrade Team: The Statistical Properties of<br />
Turbulence in the Scrape-off Layer of Upper-Single Null H<br />
and L-mode plasmas. (34 th EPS Conference on Plasma<br />
Physics, <strong>2007</strong>-07-02 to <strong>2007</strong>-07-06, Warsaw).<br />
Arnold, A., O. Prinz, D. Wagner and M. Thumm: Operation<br />
of a quasioptical multi-mode generator for 105-150 GHz.<br />
(32 nd International Conference on Infrared and Millimeter Waves<br />
and the 15 th International Conference on Terahertz Electronics<br />
(IRMMW-THz <strong>2007</strong>), <strong>2007</strong>-09-02 to <strong>2007</strong>-09-07, Cardiff).<br />
Lectures<br />
149<br />
Ascasibar, E., D. López-Bruna, F. Castejón, V. Tribaldos,<br />
H. Maaßberg, C. D. Beidler, R. Brakel, A. Dinklage, J. Geiger,<br />
J. H. Harris, A. Kus, T. Mizuuchi, S. Murakami, S. Okamura,<br />
R. Preuss, F. Sano, U. Stroth, Y. Suzuki, J. Talmadge, Y. Turkin,<br />
K. Y. Watanabe, A. Weller, A. Werner, H. Yamada and M. Yokoyama:<br />
Effect of rotational transform and shear on confinement.<br />
(Joint Conference of 17 th International Toki Conference on<br />
Physics of Flows and Turbulence in Plasmas and 16 th International<br />
Stellarator/Heliotron Workshop, <strong>2007</strong>-10-15 to<br />
<strong>2007</strong>-10-19, Ceratopia Toki, Gifu).<br />
Assas, S., L.-G. Eriksson, J.-M. Noterdaeme, C. Maggi, J. Schirmer<br />
and G. Conway: Toroidal plasma rotation with minimal<br />
momentum input in ICRF only heated ASDEX Upgrade<br />
plasmas. (17 th Topical Conference on Radio Frequency Power<br />
in Plasmas, <strong>2007</strong>-05-07 to <strong>2007</strong>-05-09, Clearwater, FL).<br />
Balden, M., C. Adelhelm, M. Sikora and M. Rasinski: Röntgenabsorptionsspektroskopie<br />
an Nano-kristallinen a-C:Me Filmen<br />
(X-ray absorption spectroscopy on nano-crystalline a-C:Me<br />
films). (2. FA-Sitzung “Strahllinien”, <strong>2007</strong>-11-09, Technische<br />
Universität Garching).<br />
Balden, M., C. Adelhelm, P. Starke, I. Lopez Galilea, C. Garcia-<br />
Rosales, A. Centeno, C. Blanco, J. Ramos Fernandez and<br />
M. Martinez Escandell: Erosion of metal-doped carbon materials<br />
by hydrogen. (13 th International Conference on Fusion<br />
Reactor Materials (ICFRM-13), <strong>2007</strong>-12-10 to <strong>2007</strong>-12-14,<br />
Nice).<br />
Baldzuhn, J., H. Ehmler, L. Genini, K. Hertel, A. Hölting,<br />
C. Sborchia and T. Schild: Cold Tests of the Superconducting<br />
Coils for the Stellarator W7-X. (Conference on Magnet Technology,<br />
MT-20, <strong>2007</strong>-08-27 to <strong>2007</strong>-08-31, Philadelphia, PA).<br />
Baudach, M., W. Bohmeyer, D. Naujoks, A. Markin and<br />
A. Cwiklinski: Zersetzung, Bildung und Transport von Kohlenwasserstoffen.<br />
(DPG AMOP-Frühjahrstagung, <strong>2007</strong>-03-19 to<br />
<strong>2007</strong>-03-23, Düsseldorf).<br />
Behler, K., H. Blank, H. Eixenberger, A. Lohs, K. Lüddecke,<br />
R. Merkel, G. Raupp, G. Schramm, W. Treutterer, M. Zilker and<br />
ASDEX Upgrade Team: Real-Time Diagnostics at ASDEX<br />
Upgrade – Architecture and Operation. (6 th IAEA Technical<br />
Meeting on Control, Data Acquisition, and Remote Participation<br />
for Fusion Research, <strong>2007</strong>-06-04 to <strong>2007</strong>-06-08,<br />
Inuyama).<br />
Behringer, K.: Aktuelle Fragen der <strong>Plasmaphysik</strong>. (WS 2006/<br />
<strong>2007</strong>, SS <strong>2007</strong>. Seminar, Universität Augsburg).<br />
Behringer, K.: Spektroskopie von Nichtgleichgewichtsplasmen.<br />
(SS <strong>2007</strong>. Vorlesung, Universität Augsburg).
Behringer, K.: Spektroskopische Diagnostik eines gepulsten<br />
Lichtbogenplasmas. (Berliner Seminar über <strong>Plasmaphysik</strong>,<br />
<strong>2007</strong>-06-05, Humboldt-Universität Berlin).<br />
Behringer, K. and U. Fantz: Physikalisches Praktikum <strong>für</strong><br />
Fortgeschrittene, Teil B. (WS 2006/<strong>2007</strong>, SS <strong>2007</strong>. Universität<br />
Augsburg).<br />
Behringer, K., U. Fantz and T. Hamacher: Probleme der<br />
zukünftigen Energieversorgung. (WS 2006/<strong>2007</strong>, SS <strong>2007</strong>.<br />
Seminar, Universität Augsburg).<br />
Behringer, K., U. Fantz and M. Schreck: Anwendungen und<br />
Diagnostik von Niederdruckplasmen. (SS <strong>2007</strong>. Vorlesung,<br />
Universität Augsburg).<br />
Behringer, K. and T. Höschen: Spektroskopische Diagnostik<br />
eines gepulsten Bogens zur Partikelsynthese. (DPG AMOP-<br />
Frühjahrstagung, <strong>2007</strong>-03-19 to <strong>2007</strong>-03-23, Düsseldorf).<br />
Behringer, K., M. Stritzker, U. Fantz and M. Schreck:<br />
Diagnostik von Niederdruckplasmen als industrielle Schlüsseltechnologie.<br />
(SS <strong>2007</strong>. Seminar, Universität Augsburg).<br />
Behrisch, R. and W. Eckstein: Sputtering by particle bombardement.<br />
(Ion Surface Interaction Conference (ISI-<strong>2007</strong>),<br />
<strong>2007</strong>-08-24 to <strong>2007</strong>-08-27, Svenigorod).<br />
Beidler, C. D., J. Geiger, H. Maaßberg, N. B. Marushchenko,<br />
Y. Turkin and W7-AS Team: Transport Modeling for W7-X<br />
on the Basis of W7-AS Experimental Results. (Joint Conference<br />
of 17 th International Toki Conference on Physics of<br />
Flows and Turbulence in Plasmas and 16 th International<br />
Stellarator/Heliotron Workshop, <strong>2007</strong>-10-15 to <strong>2007</strong>-10-19,<br />
Ceratopia Toki, Gifu).<br />
Beidler, C. D., M. Yu. Isaev, S. V. Kasilov, W. Kernbichler,<br />
H. Maaßberg, S. Murakami, V. V. Nemov, D. A. Spong and V.<br />
Tribaldus: ICNTS – Impact of Incompressible E×B Flow in<br />
Estimating Mono-Energetic Transport Coefficients. (Joint<br />
Conference of 17 th International Toki Conference on Physics<br />
of Flows and Turbulence in Plasmas and 16 th International<br />
Stellarator/Heliotron Workshop, <strong>2007</strong>-10-15 to <strong>2007</strong>-10-19,<br />
Ceratopia Toki, Gifu).<br />
Beidler, C. D., M. Y. Isaev, S. V. Kasilov, W. Kernbichler,<br />
H. Maaßberg, S. Murakami, V. V. Nemov, D. A. Spong,<br />
V. Tribaldus and G. O. Leitold: ICNTS – Benchmarking of<br />
Momentans Correction Techniques. (Joint Conference of<br />
17 th International Toki Conference on Physics of Flows and<br />
Turbulence in Plasmas and 16 th International Stellarator/<br />
Heliotron Workshop, <strong>2007</strong>-10-15 to <strong>2007</strong>-10-19, Ceratopia<br />
Toki, Gifu).<br />
Lectures<br />
150<br />
Berger, M., S. Christ-Koch, U. Fantz and NNBI Team:<br />
Diagnostics of H - Densities in RF-driven Ion Sources for<br />
Fusion Applications. (12 th International Conference on Ion<br />
Sources (ICIS), <strong>2007</strong>-08-26 to <strong>2007</strong>-08-31, Jeju, Korea).<br />
Biedermann, C.: The Berlin EBIT project and fusion relevant<br />
spectroscopy. (PEARL <strong>2007</strong>: Physics at EBIT and Advanced<br />
Research Light Sources, <strong>2007</strong>-03-08 to <strong>2007</strong>-03-12, Fudan,<br />
Shanghai).<br />
Biedermann, C., F. Allen, R. Radtke and G. Fußmann: Charge<br />
exchange of highly charged argon ions inside EBIT and with<br />
an external gas target. (10 th International Symposium on the<br />
Physics and Applications of Electron Beam Ion Sources and<br />
Traps (EBIS/T <strong>2007</strong>), <strong>2007</strong>-08-01 to <strong>2007</strong>-08-04, Heidelberg).<br />
Bobkov, V.: Specific aspects of the ASDEX Upgrade (AUG)<br />
ICRF system. Implications and suggestions for JET and<br />
ITER. (ICRF Meetings <strong>2007</strong> (TFH/JET-ITER/EnTicE/EFDA<br />
Coordination Task Meeting), <strong>2007</strong>-04-16 to <strong>2007</strong>-04-20,<br />
Schloss Ringberg, Tegernsee).<br />
Bobkov, V., F. Braun, R. Dux, A. Herrmann, A. Kallenbach,<br />
R. Neu, J.-M. Noterdaeme, Th. Pütterich and ASDEX Upgrade<br />
Team: Tungsten sputtering during ICRF in ASDEX Upgrade.<br />
(17 th Topical Conference on Radio Frequency Power in Plasmas,<br />
<strong>2007</strong>-05-07 to <strong>2007</strong>-05-09, Clearwater, FL).<br />
Bolt, H.: Cross cutting European research on materials for extreme<br />
environments. (13 th International Conference on Fusion<br />
Reactor Materials (ICFRM-13), <strong>2007</strong>-12-10 to <strong>2007</strong>-12-14, Nice).<br />
Bolt, H.: Materialforschung <strong>für</strong> den Fusionsreaktor. (DGM<br />
Fachausschusssitzung “Metallische Verbundwerkstoffe und<br />
zelluläre Metalle”, <strong>2007</strong>-11-06, Garching).<br />
Bolt, H.: Materialfragen in der Kernfusion. (Studentenkolloqium,<br />
<strong>2007</strong>-05-16, Universität Clausthal-Zellerfeld).<br />
Bolt, H.: Materials challenges for the plasma-facing components<br />
of fusion reactors. (Kolloqiumsvortrag, <strong>2007</strong>-02-22,<br />
University of Oxford).<br />
Bolt, H.: New materials for extreme conditions. (EU Workshop<br />
on Basic Research and Innovative Science for Energy<br />
(BRISE), <strong>2007</strong>-05-24, Brussels).<br />
Bolt, H.: Outline of a fusion materials CSA. (EFDA Fusion<br />
Materials Workshop, <strong>2007</strong>-03-02, Garching).<br />
Bolt, H.: Wolfram als plasmabelastetes Material <strong>für</strong> Fusionsanlagen.<br />
(Kolloqiumsvortrag, <strong>2007</strong>-01-12, Forschungszentrum<br />
Karlsruhe).
Bolt, H. and M. Balden: Oberflächentechnologie (OT). (SS <strong>2007</strong>.<br />
Vorlesung, Technische Universität München).<br />
Bolt, H., M. Balden, A. Brendel, F. Koch, D. Levchuk, H. Maier,<br />
K. Ertl, J. Roth, A. Wiltner, F. Kost and K. Schmid: Neue<br />
Materialien <strong>für</strong> den Einsatz unter extremen Anforderungen<br />
in der Kernfusion. (ISC-Seminar, <strong>2007</strong>-02-02, Fraunhofer-<br />
<strong>Institut</strong> <strong>für</strong> Silicatforschung, Würzburg).<br />
Bolt, H. and J. You: Dünne Schichten. (WS 2006/<strong>2007</strong>.<br />
Vorlesung, Technische Universität München).<br />
Bongers, W. A., M. F. Graswinckel, M. A. Van den Berg,<br />
A. Bruschi, I. Danilov, A. J. H. Donne, B. S. Q. Elzendoorn,<br />
A. P. H. Goede, R. Heidinger, M. A. Henderson, O. G. Kruijt,<br />
B. Kruizinga, N. Lopes Cardozo, A. Moro, E. Poli, D. M. S. Ronden<br />
and A. G. A. Verhoeven: Recent developments of the Upper<br />
port ECH&CD Launcher systems for ITER based on the<br />
Remote Steering concept. (4 th IAEA Technical Meeting on<br />
ECRH Physics and Technology for ITER, <strong>2007</strong>-06-06 to<br />
<strong>2007</strong>-06-08, Vienna).<br />
Bosch, H.-S.: Kernfusion – Was wir von den Sternen <strong>für</strong><br />
unsere Energieversorgung lernen können. (Schulvortrag der<br />
MPG-Hauptversammlung <strong>2007</strong>, <strong>2007</strong>-06-26, Kiel).<br />
Bottino, A., S. Jolliet, A. G. Peeters and R. Hatzky: Global<br />
low noise particle simulations of ETG and ITG turbulence.<br />
(US-Japan Joint <strong>Institut</strong>e for Fusion Theory (JIFT) Workshop,<br />
<strong>2007</strong>-01-10, San Diego, CA).<br />
Bovshuk, V. R., W. A. Cooper, M. I. Mikhailov, J. Nührenberg<br />
and V. D. Shafranov: Search for very-high-beta MHD stable<br />
quasi-isodynamic configurations. (Joint Conference of 17 th International<br />
Toki Conference on Physics of Flows and Turbulence<br />
in Plasmas and 16 th International Stellarator/Heliotron<br />
Workshop, <strong>2007</strong>-10-15 to <strong>2007</strong>-10-19, Ceratopia Toki,<br />
Gifu).<br />
Bradshaw, A. M.: Energy research: short term needs and long<br />
term strategy. (The 3 rd Transatlantic Market Conference –<br />
Growth & Security: Energy and Energy Transportation,<br />
<strong>2007</strong>-05-13 to <strong>2007</strong>-05-15, Washington, D.C.).<br />
Bradshaw, A. M.: Fusion Energy: Bringing the Sun Down to<br />
Earth, the Real Challenge of the 21 st Century. (Sustainable<br />
Neighbourhood 4 th BMBF Forum for Sustainability <strong>2007</strong>,<br />
<strong>2007</strong>-05-08 to <strong>2007</strong>-05-10, Leipzig).<br />
Bradshaw, A. M.: The future of our energy supply: What comes<br />
after fossil fuels? (Deutsch-Britische Gesellschaft, <strong>2007</strong>-03-15,<br />
Internationales Begegnungszentrum (IBZ), Garching).<br />
Lectures<br />
151<br />
Bradshaw, A. M.: ITER – the way to fusion energy. (Seminar,<br />
Physics Department Trinity College, <strong>2007</strong>-03-02, Dublin).<br />
Bradshaw, A. M.: ITER: Der Weg zur Fusionsenergie. (Collegium<br />
Europaeum Jenense, <strong>2007</strong>-12-05, Universität Jena).<br />
Bradshaw, A. M.: ITER: Der Weg zur Fusionsenergie.<br />
(Physikalisches Kolloquium, <strong>2007</strong>-01-15, Universität Ulm).<br />
Bradshaw, A. M.: ITER: Der Weg zur Fusionsenergie.<br />
(Workshop des Graduiertenkollegs Hochenergiephysik und<br />
Teilchenastrophysik, <strong>2007</strong>-10-10, Freudenstadt).<br />
Bradshaw, A. M.: Kernfusion als Energiequelle der Zukunft.<br />
(Rheno-Franconia Dies Academicus, <strong>2007</strong>-01-24, München).<br />
Bradshaw, A. M.: Kernfusion als Energiequelle der Zukunft.<br />
(Rotary Club Meeting, <strong>2007</strong>-10-30, Gauting Würmtal).<br />
Bradshaw, A. M.: Kernfusion: eine nachhaltige Energietechnologie.<br />
(Energiegespräche Ossiach, <strong>2007</strong>-06-13, Ossiach).<br />
Bradshaw, A. M.: Nuclear fusion: An energy source for tomorrow.<br />
(World Economic Forum <strong>Annual</strong> Meeting, <strong>2007</strong>-01-24<br />
to <strong>2007</strong>-01-28, Davos).<br />
Bradshaw, A. M.: Nuclear fusion and ITER for non-experts.<br />
(Britisch Science Officers Conference, <strong>2007</strong>-03-28 to <strong>2007</strong>-03-30,<br />
Berlin).<br />
Bradshaw, A. M.: The roadmap for nuclear fusion. (The 15 th<br />
International Conference on Vacuum Ultraviolet Radiation<br />
Physics, <strong>2007</strong>-07-29 to <strong>2007</strong>-08-03, Berlin).<br />
Bradshaw, A. M.: The roadmap for nuclear fusion. (Symposium<br />
on Vacuum Based Science and Technology; Rudolf<br />
Jaeckel-Preis <strong>2007</strong> der DVG, <strong>2007</strong>-09-05 to <strong>2007</strong>-09-07,<br />
Greifswald).<br />
Bradshaw, A. M.: Der Sonnen-Imitator. Neuer Plasma-<br />
Modus kann die Energieausbeute des geplanten Fusionstestreaktors<br />
ITER verdoppeln. (The Power of Ideas, <strong>2007</strong>-06-07,<br />
Kühlungsborn, Heiligendamm).<br />
Brandt, C., O. Grulke and T. Klinger: Einfluss raumzeitlicher<br />
elektrostatischer und elektromagnetischer Felder auf Driftwellen.<br />
(DPG AMOP-Frühjahrstagung, <strong>2007</strong>-03-19 to<br />
<strong>2007</strong>-03-23, Düsseldorf).<br />
Braun, F.: Faraday shield RF modelling and RF sheath dissipation.<br />
(ITER – ICH Working Group Meeting 8, <strong>2007</strong>-01-11<br />
to <strong>2007</strong>-01-12, Cadarache).
Braun, F. and J.-M. Noterdaeme: Simulations of different<br />
Faraday screen configurations for the ITER ICRH antenna.<br />
(17 th Topical Conference on Radio Frequency Power in<br />
Plasmas, <strong>2007</strong>-05-07 to <strong>2007</strong>-05-09, Clearwater, FL).<br />
Braune, H., P. Brand, V. Erckmann, H. P. Laqua, L. Jonitz,<br />
W. Leonhardt, D. Mellein, G. Michel, F. Noke, F. Purps,<br />
K. H. Schlüter, M. Winkler and W7-X ECRH Teams at <strong>IPP</strong>,<br />
IPF and FZK: Operation experiences with the HV-system<br />
for the ECRH installation at W7-X. (19 th Joint Russian-<br />
German Workshop on ECRH and Gyrotrons, <strong>2007</strong>-07-18 to<br />
<strong>2007</strong>-07-24, Garching).<br />
Brendel, A., T. Köck and H. Bolt: Mechanical Properties of<br />
SiC long fibre reinforced Copper. (13 th International Conference<br />
on Fusion Reactor Materials (ICFRM-13), <strong>2007</strong>-12-10<br />
to <strong>2007</strong>-12-14, Nice).<br />
Brendel, A., T. Köck, T. Brendel and H. Bolt: SiC long fibre<br />
reinforced copper for the divertor heat sink. (European Congress<br />
and Exhibition on Advanced Materials and Processes<br />
(EUROMAT <strong>2007</strong>), <strong>2007</strong>-09-10 to <strong>2007</strong>-09-13, Nürnberg).<br />
Bronold, F. X., K. Matyash, D. Tskhakaya, R. Schneider and<br />
H. Fehske: Particle-in-cell Monte Carlo model for oxygen<br />
discharges. (DPG AMOP-Frühjahrstagung, <strong>2007</strong>-03-19 to<br />
<strong>2007</strong>-03-23, Düsseldorf).<br />
Buchner, C., R. Haller, E. Harmeyer, J. Mühlbacher, A. Wieczorek<br />
and H. Wobig: Investigation on Power Supply Operation for<br />
the Helias Stellarator Fusion Reactor. (EPE <strong>2007</strong> – 12 th European<br />
Conference on Power Electronics and Applications,<br />
<strong>2007</strong>-09-02 to <strong>2007</strong>-09-05, Aalborg).<br />
Buchner, C., E. Harmeyer, J. , A. Wieczorek and H. Wobig:<br />
Investigation and Optimization on Auxiliary System Operation<br />
of a Helias Fusion Reactor. (<strong>2007</strong> IEEE International<br />
Symposium on Industrial Electronics (ISIE <strong>2007</strong>), <strong>2007</strong>-06-04<br />
to <strong>2007</strong>-06-07, Vigo).<br />
Bykov, V., F. Schauer, P. Eeten van and A. Tereshchenko:<br />
Main Results and Critical Issues of W7-X Structural Analysis.<br />
(22 nd Symposium on Fusion Engineering (SOFE 07),<br />
<strong>2007</strong>-06-17 to <strong>2007</strong>-06-21, Albuquerque, NM).<br />
Cantarini, J., J. P. Knauer and E. Pasch: Design study of<br />
the observation optics for the Thomson scattering system<br />
planned at Wendelstein 7-X. (PLASMA <strong>2007</strong> – International<br />
Conference on Research and Applications of Plasmas combined<br />
with the 4 th German-Polish Conference on Plasma<br />
Diagnostics for Fusion and Applications and the 6 th French-<br />
Polish Seminar on Thermal Plasma in Space and Laboratory,<br />
<strong>2007</strong>-10-16 to <strong>2007</strong>-10-19, Greifswald).<br />
Lectures<br />
152<br />
Cardella, A., L. Giordano, G. Crespi and T. Scholz: Development<br />
of a Portable Reaming Tool for the Supporting<br />
Structures of Wendelstein 7-X. (22 nd IEEE/NPSS Symposium<br />
on Fusion Engineering, <strong>2007</strong>-06-18 to <strong>2007</strong>-06-22,<br />
Albuquerque, NM).<br />
Carvalho, P., H. Thomsen, S. Gori, U. von Toussaint, A. Weller,<br />
R. Coelho, A. Neto, T. Pereira, C. Silva and H. Fernandes:<br />
Fast tomographic methods on the tokamak ISTTOK. (PLASMA<br />
<strong>2007</strong> – International Conference on Research and Applications<br />
of Plasmas combined with the 4 th German-Polish<br />
Conference on Plasma Diagnostics for Fusion and Applications<br />
and the 6 th French-Polish Seminar on Thermal<br />
Plasma in Space and Laboratory, <strong>2007</strong>-10-16 to <strong>2007</strong>-10-19,<br />
Greifswald).<br />
Chauhana, N., S. Kamakshia, A. Kumara, A. Mittala, D. Wagner,<br />
M. V. Kartikeyan and M. K. Thumm: Design and Optimization<br />
of non-linear tapers for high power gyrotrons.<br />
(22 nd National Symposium on Plasma Science & Technology<br />
(PLASMA-<strong>2007</strong>), <strong>2007</strong>-12-06 to <strong>2007</strong>-12-10, Ahmedabad).<br />
Christ-Koch, S., U. Fantz and NNBI Team: Ortsaufgelöste<br />
Messung der negativen Wasserstoffionendichte in einer HF-<br />
Quelle. (DPG AMOP-Frühjahrstagung, <strong>2007</strong>-03-19 to<br />
<strong>2007</strong>-03-23, Düsseldorf).<br />
Colas, L., A. Ekedahl, M. Goniche, J. P. Gunn, B. Nold, Y. Corre,<br />
M.-L. Mayoral, K. Kirov, J. Mailloux, S. Heuraux, E. Faudot,<br />
V. Petrzilka, V. Bobkov, R. Dux, ASDEX Upgrade Team and<br />
JET-EFDA Contributors: RF-induced modifications in the<br />
scrape-off layer of magnetic fusion devices: a 2D spatial<br />
structure. (34 th EPS Conference on Plasma Physics and<br />
Controlled Fusion, <strong>2007</strong>-07-02 to <strong>2007</strong>-07-06, Warsaw).<br />
Conway, G. D., C. Troester, J. Schirmer, C. Angioni, E. Holzhauer,<br />
F. Jenko, F. Merz, E. Poli, B. Scott and W. Suttrop: Doppler<br />
reflectometry on ASDEX Upgrade: Foundations and latest<br />
results. (8 th International Reflectometry Workshop (IRW8),<br />
<strong>2007</strong>-05-02 to <strong>2007</strong>-05-04, St. Petersburg).<br />
Counsell, G., P. Coad, J. A. Ferreira, M. Rubel, F. L. Tabares,<br />
A. Widdowson, P. Sundelin, V. Philipps, G. Sergienko, D. Tafalla,<br />
I. Tanarro, V. Herrero, C. Gomez-Aleixandre, J. M. Albella,<br />
P. Gasior, J. Wolowski, J. Likonen, C. Grisolia, A. Semerok,<br />
C. Hopf, W. Jacob, M. Schlüter, D. Farcage, D. Hole, T. Renvall<br />
and P. Y. Thro: Progress with Tritium Removal and Mitigation<br />
2006-7. (6 th Meeting of Contact Persons of the EU-PWI<br />
Task Force, <strong>2007</strong>-10-29 to <strong>2007</strong>-10-31, Madrid).<br />
Croari, G. and J. Baldzuhn: Acceptance Tests on the W7-X Coils.<br />
(International Youth Conference on Energetics, <strong>2007</strong>-05-31<br />
to <strong>2007</strong>-06-02, Budapest).
Cwiklinski, A., A. Markin, M. Baudach and W. Bohmeyer:<br />
Interaction between Nitrogen and Hydrocarbons in Magnetized<br />
Plasmas. (PLASMA <strong>2007</strong> – International Conference<br />
on Research and Applications of Plasmas combined with the<br />
4 th German-Polish Conference on Plasma Diagnostics for<br />
Fusion and Applications and the 6 th French-Polish Seminar<br />
on Thermal Plasma in Space and Laboratory, <strong>2007</strong>-10-16 to<br />
<strong>2007</strong>-10-19, Greifswald).<br />
D’Inca, R., S. Assas, V. Bobkov, F. Braun, B. Eckert and<br />
J.-M. Noterdaeme: Comparison of different arc detection methods<br />
during plasma operations with ICRF heating on ASDEX<br />
Upgrade. (17 th Topical Conference on Radio Frequency Power<br />
in Plasmas, <strong>2007</strong>-05-07 to <strong>2007</strong>-05-09, Clearwater, FL).<br />
Da Graça, S., G. Conway, P. Lauber, M. Maraschek, D. Borba,<br />
S. Günter, L. Cupido, K. Sassenberg, F. Serra, M. E. Manso,<br />
CFN Reflectometry Group and ASDEX Upgrade Team:<br />
Localization of MHD and fast particle modes using reflectometry<br />
in ASDEX Upgrade. (8 th International Reflectometry<br />
Worskhop (IRW8), <strong>2007</strong>-05-02 to <strong>2007</strong>-05-04, St. Petersburg).<br />
Dietrich, S., S. Christ, B. Crowley and U. Fantz: Electrical<br />
probes for electron energy distribution function (EEDF)<br />
measurements in low pressure hydrogen plasmas. (28 th International<br />
Conference on Phenomena in Ionized Gases (ICPIG),<br />
<strong>2007</strong>-07-15 to <strong>2007</strong>-07-20, Prague).<br />
Dietrich, S. and U. Fantz: Messung der Elektronendichte<br />
mittels optischer Emissionsspektroskopie (OES) und Vergleich<br />
mit anderen diagnostischen Methoden. (DPG AMOP-Frühjahrstagung,<br />
<strong>2007</strong>-03-19 to <strong>2007</strong>-03-23, Düsseldorf).<br />
Dinklage, A., E. Ascasibar, C. D. Beidler, R. Brakel, R. Burhenn,<br />
F. Castejon, T. Estrada, H. Funaba, Y. Feng, J. Geiger, J. H. Harris,<br />
C. Hidalgo, K. Ida, M. Kobayashi, R. König, G. Kühner, A. Kus,<br />
D. Lopez Bruna, H. Maaßberg, D. Mikkelsen, T. Mizuuchi,<br />
N. Nakajima, R. Preuss, S. Sakakibara, F. Sano, F. Sardei,<br />
U. Stroth, Y. Suzuki, J. Talmadge, H. Thomsen, B. P. Van Milligen,<br />
K. Y. Watanabe, A. Weller, A. Werner, R. Wolf, H. Yamada<br />
and M. Yokoyama: Status of the International Stellarator/<br />
Heliotron Profile Database. (Joint Conference of 17 th International<br />
Toki Conference on Physics of Flows and Turbulence<br />
in Plasmas and 16 th International Stellarator/Heliotron Workshop,<br />
<strong>2007</strong>-10-15 to <strong>2007</strong>-10-19, Ceratopia Toki, Gifu).<br />
Dinklage, A., B. Bruhn, H. Testrich and C. Wilke: Hysterese von<br />
Ionisationswellen. (DPG AMOP-Frühjahrstagung, <strong>2007</strong>-03-19<br />
to <strong>2007</strong>-03-23, Düsseldorf).<br />
Dinklage, A., H. Dreier, R. Fischer, S. Gori, R. Preuss and<br />
U. von Toussaint: Integrated data analysis for fusion: A<br />
Lectures<br />
153<br />
Bayesian Tutorial for Diagnosticians. (International Workshop<br />
on Burning Plasma Diagnostics, <strong>2007</strong>-09-24 to <strong>2007</strong>-09-28,<br />
Varenna).<br />
Dodt, D. and A. Dinklage: Effect of Uncertainties in a Collisional-Radiative<br />
Model of a Gas Discharge. (DPG AMOP-<br />
Frühjahrstagung, <strong>2007</strong>-03-19 to <strong>2007</strong>-03-23, Düsseldorf).<br />
Dodt, D., A. Dinklage, R. Fischer, K. Bartschat and O. Zatsarinny:<br />
Form-Free Reconstruction of an Electron Energy Distribution<br />
Function from Optical Emission Spectroscopy. (PLASMA<br />
<strong>2007</strong> – International Conference on Research and Applications<br />
of Plasmas combined with the 4 th German-Polish Conference<br />
on Plasma Diagnostics for Fusion and Applications and the<br />
6 th French-Polish Seminar on Thermal Plasma in Space and<br />
Laboratory, <strong>2007</strong>-10-16 to <strong>2007</strong>-10-19, Greifswald).<br />
Dodt, D., A. Dinklage, R. Fischer, K. Bartschat and O. Zatsarinny:<br />
Integrated Data Analysis of Spectroscopic Data. (Joint Conference<br />
of 17 th International Toki Conference on Physics of<br />
Flows and Turbulence in Plasmas and 16 th International<br />
Stellarator/Heliotron Workshop, <strong>2007</strong>-10-15 to <strong>2007</strong>-10-19,<br />
Ceratopia Toki, Gifu).<br />
Dodt, D., A. Dinklage, R. Fischer and R. Preuss: Spatially<br />
Resolved Electron Energy Distributions of a Discharge<br />
Plasma from Optical Emission Spectroscopy. (27 th International<br />
Workshop on Bayesian Inference and <strong>Max</strong>imum<br />
Entropy Methods in Science and Engineering, <strong>2007</strong>-07-08<br />
to <strong>2007</strong>-07-13, New York, NY).<br />
Dreier, H., A. Dinklage, R. Fischer, M. Hirsch and P. Kornejew:<br />
Bayesian diagnostic design of a multichannel interferometer.<br />
(34 th European Physical Society Conference on Plasma Physics,<br />
<strong>2007</strong>-07-02 to <strong>2007</strong>-07-06, Warsaw).<br />
Dreier, H., A. Dinklage, R. Fischer, M. Hirsch and P. Kornejew:<br />
Optimisation of the line of sight configuration of the multichannel<br />
interferometer at Wendelstein 7-X. (PLASMA <strong>2007</strong> –<br />
International Conference on Research and Applications of<br />
Plasmas combined with the 4 th German-Polish Conference<br />
on Plasma Diagnostics for Fusion and Applications and the<br />
6 th French-Polish Seminar on Thermal Plasma in Space and<br />
Laboratory, <strong>2007</strong>-10-16 to <strong>2007</strong>-10-19, Greifswald).<br />
Dreier, H., A. Dinklage and R. Preuss: Bayesian diagnostic<br />
design of a multichannel interferometer. (17 th International<br />
Toki Conference/16 th International Stellarator Workshop,<br />
<strong>2007</strong>-10-15 to <strong>2007</strong>-10-19, Toki).<br />
Dreier, H., R. Preuss, A. Dinklage and V. Dose: Data adaptive<br />
control parameter estimation for scaling laws. (DPG AMOP-<br />
Frühjahrstagung, <strong>2007</strong>-03-19 to <strong>2007</strong>-03-23, Düsseldorf).
Dreier, H., R. Preuss, A. Dinklage and V. Dose: Physical<br />
data assessment for energy confinement scaling laws. (Joint<br />
Conference of 17 th International Toki Conference on Physics<br />
of Flows and Turbulence in Plasmas and 16 th International<br />
Stellarator/Heliotron Workshop, <strong>2007</strong>-10-15 to <strong>2007</strong>-10-19,<br />
Ceratopia Toki, Gifu).<br />
Dumbrajs, O., V. Igochine and H. Zohm: Diffusion in a stochastic<br />
magnetic field in ASDEX Upgrade. (Biennial Workshop<br />
“Stochasticity in Fusion Plasmas” (SFP <strong>2007</strong>), <strong>2007</strong>-03-05<br />
to <strong>2007</strong>-03-07, Jülich).<br />
Dux, R.: Impurities and exhaust with improved confinement.<br />
(EPFW Meeting, <strong>2007</strong>-12-03 to <strong>2007</strong>-12-05, Prague).<br />
Dux, R.: <strong>Plasmaphysik</strong> und Fusionsforschung. (SS <strong>2007</strong>.<br />
Proseminar, Technische Universität München, Garching).<br />
Dux, R. and A. M. Bradshaw: <strong>Plasmaphysik</strong> und Fusionsforschung.<br />
(SS <strong>2007</strong>. Proseminar, Technische Universität<br />
München, Garching).<br />
Eckstein, W.: The Sputtering Yield. (Ion Surface Interaction<br />
Conference (ISI-<strong>2007</strong>), <strong>2007</strong>-08-24 to <strong>2007</strong>-08-27, Svenigorod).<br />
Eeten P. van, D. Hathiramani, V. Bykov and A. Cardella:<br />
Design and test of the support elements of the W7-X superconducting<br />
magnets. (22 nd Symposium on Fusion Engineering<br />
(SOFE 07), <strong>2007</strong>-06-17 to <strong>2007</strong>-06-21, Albuquerque, NM).<br />
Eich, T., A. Kallenbach, P. McCarthy, J. Neuhauser, G. Pautasso<br />
and ASDEX Upgrade Team: In/Out power load asymmeries<br />
during type-I ELMs in ASDEX Upgrade. (34 th EPS Conference<br />
on Plasma Physics, <strong>2007</strong>-07-02 to <strong>2007</strong>-07-08, Warsaw).<br />
Erckmann, V., P. Brand, H. Braune, G. Dammertz, G. Gantenbein,<br />
W. Kasparek, H. P. Laqua, G. Michel, M. Schmid, M. Thumm,<br />
M. Weißgerber, W7X ECRH Team at <strong>IPP</strong> Greifswald, W7-X<br />
Team at FZK Karlsruhe and W7-X Team at IPF Stuttgart:<br />
The W7-X ECRH Plant: Recent Achievements. (17 th Topical<br />
Conference on Radio Frequency Power in Plasmas, <strong>2007</strong>-05-07<br />
to <strong>2007</strong>-05-09, Clearwater, FL).<br />
Erckmann, V., M. Schmid, H. P. Laqua, G. Dammertz, S. Illy,<br />
H. Braune, F. Hollmann, F. Noke, F. Purps, ECRH Team at<br />
<strong>IPP</strong> Greifswald, ECRH Team at FZK Karlsruhe and ECRH<br />
Team at IPF Stuttgart: Advanced Gyrotron Collector Sweeping<br />
with smooth Power Distribution. (4 th IAEA Technical Meeting<br />
on ECRH Physics and Technology for ITER, <strong>2007</strong>-06-06 to<br />
<strong>2007</strong>-06-08, Vienna).<br />
Evans, T. E., J. G. Watkins, I. Joseph, R. Moyer, J. Yu, M. Jakubowski<br />
and O. Schmitz: 3D structures and dynamics of ELMs.<br />
Lectures<br />
154<br />
(49 th <strong>Annual</strong> APS Division of Plasma Physics Meeting,<br />
<strong>2007</strong>-11-12 to <strong>2007</strong>-11-16, Orlando, FL).<br />
Fantz, U.: Compilation, calculation and validaiton of fundamental<br />
data for diatomic molecules. (CRP (Co-ordinated<br />
Research Project) on “Atomic and Molecular Data for Plasma<br />
Modelling”, <strong>2007</strong>-06-18 to <strong>2007</strong>-06-20, Vienna).<br />
Fantz, U.: Diagnostik und Modellierung der NNBI Teststände<br />
– wozu ? (<strong>IPP</strong> Summer University for Plasma Physics,<br />
<strong>2007</strong>-09-24 to <strong>2007</strong>-09-28, Greifswald).<br />
Fantz, U.: Low pressure and high power RF sources for negative<br />
hydrogen ions for fusion applications (ITER NBI). (12 th International<br />
Conference on Ion Sources (ICIS), <strong>2007</strong>-08-26 to<br />
<strong>2007</strong>-08-31, Jeju).<br />
Fantz, U.: Neutral beam injection for present and future<br />
fusion devices. (<strong>IPP</strong> Summer University for Plasma Physics,<br />
<strong>2007</strong>-09-24 to <strong>2007</strong>-09-28, Greifswald).<br />
Fantz, U.: Neutral beam injection for present and future<br />
fusion devices. (Seminar, <strong>2007</strong>-11-12 to <strong>2007</strong>-11-16, Schloss<br />
Ringberg, Tegernsee).<br />
Fantz, U.: Regenbogen, Blitze und Polarlichter. (Lange<br />
Nacht der Wissenschaft, <strong>2007</strong>-10-13, Garching).<br />
Fantz, U.: Plasma homogeneity of large RF sources: spectroscopy<br />
and probes at <strong>IPP</strong> testbeds. (International CCNB<br />
Meeting, <strong>2007</strong>-05-22 to <strong>2007</strong>-05-24, Culham).<br />
Fantz, U.: <strong>Plasmaphysik</strong> und Fusionsforschung I. (WS 2006/<br />
<strong>2007</strong>. Vorlesung, Universität Augsburg).<br />
Fantz, U.: <strong>Plasmaphysik</strong> und Fusionsforschung II. (SS <strong>2007</strong>.<br />
Vorlesung, Universität Augsburg).<br />
Fantz, U., P. Franzen, H. D. Falter, W. Kraus, M. Berger,<br />
S. Christ-Koch, M. Fröschle, R. Gutser, B. Heinemann, S. Leyer,<br />
C. Martens, P. McNeely, R. Riedl, E. Speth and D. Wünderlich:<br />
Development of a Negative Ion RF Source for ITER NBI.<br />
(34 th EPS Conference on Plasma Physics, <strong>2007</strong>-07-02 to<br />
<strong>2007</strong>-07-06, Warsaw).<br />
Fantz, U., P. Franzen, H. D. Falter, W. Kraus, M. Berger,<br />
S. Christ-Koch, M. Fröschle, R. Gutser, B. Heinemann,<br />
C. Martens, P. McNeely, R. Riedl, E. Speth and D. Wünderlich:<br />
Large low pressure, high power RF sources for negative hdyrogen<br />
ions for fusion applications. (28 th International Conference<br />
on Phenomena in Ionized Gases (ICPIG), <strong>2007</strong>-07-15 to<br />
<strong>2007</strong>-07-20, Prague).
Fantz, U., P. Franzen, H. D. Falter, W. Kraus, M. Berger,<br />
S. Christ-Koch, M. Fröschle, R. Gutser, B. Heinemann,<br />
C. Martens, P. McNeely, R. Riedl, E. Speth and D. Wünderlich:<br />
Low Pressure and High Power RF Sources for Negative<br />
Hydrogen Ions for Fusion Applications (ITER NBI). (International<br />
Conference on Ion Sources (ICIS), <strong>2007</strong>-08-26 to<br />
<strong>2007</strong>-08-31, Jeju, Korea).<br />
Feketeova, L., S. Feil, V. Grill, N. Endstrasser, B. Rasul,<br />
W. Schustereder, A. Bacher, S. Matt-Leubner, F. Zappa, P. Scheier<br />
and T. Märk: Elementary plasma reactions revisited: Electron<br />
ionization and ion surface reactions relevant for fusion<br />
plasmas. (16 th Symposium on Applications of Plasma Processes<br />
(SAPP XVI), <strong>2007</strong>-01-20 to <strong>2007</strong>-01-25, Podbanské).<br />
Feng, Y., M. Kobayashi, N. Ashikawa, L. Giannone, R. König,<br />
LHD Experimental Group, S. Masuzaki, K. McCormick,<br />
J. Miyazawa, T. Morisaki, S. Morita, O. Motojima, Y. Nakamura,<br />
K. Narihara, N. Ohyabu, B. J. Peterson, F. Sardei, K. Sato, M. Shoji,<br />
N. Tamura, H. Thomsen, M. Tokitani, F. Wagner, U. Wenzel,<br />
H. Yamada and I. Yamada: Comparative Divertor-Transport<br />
Study for W7-AS and LHD. (Joint Conference of 17 th International<br />
Toki Conference on Physics of Flows and Turbulence<br />
in Plasmas and 16 th International Stellarator/Heliotron<br />
Workshop, <strong>2007</strong>-10-15 to <strong>2007</strong>-10-19, Ceratopia Toki, Gifu).<br />
Fernandez, A., D. Wagner, A. Cappa, G. Müller and A. Tolkachev:<br />
EC waves polarization control in the TJ-II, IRMMW-THz<br />
<strong>2007</strong>. (32 nd International Conference on Infrared and Millimeter<br />
Waves and the 15 th International Conference on Terahertz<br />
Electronics (IRMMW-THz <strong>2007</strong>), <strong>2007</strong>-09-02 to<br />
<strong>2007</strong>-09-07, Cardiff).<br />
Fischer, R.: Integrated Data Analysis of Complementary<br />
Experiments. (27 th International Workshop on Bayesian<br />
Inference and <strong>Max</strong>imum Entropy Methods in Science and<br />
Engineering (<strong>Max</strong>Ent <strong>2007</strong>), <strong>2007</strong>-07-08 to <strong>2007</strong>-07-13,<br />
Saratoga Springs, NY).<br />
Fischer, R. and A. Dinklage: The concept of integrated data<br />
analysis of complementary experiments. (27 th International<br />
Workshop on Bayesian Inference and <strong>Max</strong>imum Entropy Methods<br />
in Science and Engineering (<strong>Max</strong>Ent <strong>2007</strong>), <strong>2007</strong>-07-08<br />
to <strong>2007</strong>-07-13, Saratoga Springs, NY).<br />
Flaws, A., A. Gude, V. Igochine, C. Maggi, M. Maraschek<br />
and H. Zohm: The Role of Magneto-Hydrodynamic Instabilities<br />
in the Improved H-Mode Scenario. (DPG AMOP-<br />
Frühjahrstagung, <strong>2007</strong>-03-19 to <strong>2007</strong>-03-23, Düsseldorf).<br />
Franzen, P.: Status and Plans of the RF source development<br />
at <strong>IPP</strong> Garching. (Coordinating Committee on Neutral Beams<br />
(CCNB-Meeting), <strong>2007</strong>-05-22 to <strong>2007</strong>-05-24, Culham).<br />
Lectures<br />
155<br />
Frerichs, H., D. Harting, D. Reiter and Y. Feng: Numerical<br />
investigation of impurity transport in the ergodized edge<br />
plasma at TEXTOR-DED. (DPG AMOP-Frühjahrstagung,<br />
<strong>2007</strong>-03-19 to <strong>2007</strong>-03-23, Düsseldorf).<br />
Fröschle, M., B. Heinemann, R. Riedl, A. Stäbler and E. Speth:<br />
Progress in the Development of High Heat Flux Panels for NBI in<br />
AUG. (CCNB – Combined ITER Design and R&D Review and<br />
Co-ordination Meeting, <strong>2007</strong>-11-28 to <strong>2007</strong>-12-01, Ahmedabad).<br />
Funaba, H., A. Dinklage, H. Yamada, M. Yokoyama, K. Watanabe,<br />
K. Narihara, I. Yamada, K. Tanaka, T. Tokuzawa, S. Murakami,<br />
M. Osakabe, K. Kawahata and LHD Experimental Group:<br />
Data structure for LHD plasmas in the international profile<br />
database. (Joint Conference of 17 th International Toki Conference<br />
on Physics of Flows and Turbulence in Plasmas and<br />
16 th International Stellarator/Heliotron Workshop, <strong>2007</strong>-10-15<br />
to <strong>2007</strong>-10-19, Ceratopia Toki, Gifu).<br />
Fußmann, G.: Einführung in die <strong>Plasmaphysik</strong>. (WS 2006/<strong>2007</strong>.<br />
Vorlesung, Humboldt-Universität Berlin).<br />
Fußmann, G.: Kugelblitze, gibt es sie? (Greifswalder Physikalisches<br />
Kolloquium, <strong>2007</strong>-07-19, Universität Greifswald).<br />
Fußmann, G.: Kugelblitze, gibt es sie? (Physikalisches Kolloquium,<br />
<strong>2007</strong>-07-09, Ruhr-Universität Bochum).<br />
Fußmann, G.: <strong>Plasmaphysik</strong> und Fusionsforschung. (SS <strong>2007</strong>.<br />
Vorlesung, Humboldt-Universität Berlin).<br />
Fußmann, G.: Spektroskopische Analyse von Fusionsplasmen.<br />
(108. Jahrestagung der Deutschen Gesellschaft <strong>für</strong><br />
Angewandte Optik, <strong>2007</strong>-05-29 to <strong>2007</strong>-06-02, Heringsdorf).<br />
Fußmann, G., B. Jüttner, S. Noack and A. Versteegh: Ball<br />
lightning – an old puzzle revisited. (PLASMA <strong>2007</strong> – International<br />
Conference on Research and Applications of Plasmas<br />
combined with the 4 th German-Polish Conference on Plasma<br />
Diagnostics for Fusion and Applications and the 6 th French-<br />
Polish Seminar on Thermal Plasma in Space and Laboratory,<br />
<strong>2007</strong>-10-16 to <strong>2007</strong>-10-19, Greifswald).<br />
Gantenbein, G., H. Braune, G. Dammertz, V. Erckmann, S. Illy,<br />
W. Kasparek, H. P. Laqua, C. Lechte, F. Legrand, C. Lievin,<br />
W. Leonhardt, G. Michel, F. Noke, B. Piosczyk, F. Purps, M. Schmid<br />
and M. Thumm: 1 MW, 140 GHz, CW gyrotron for W7-X.<br />
Status report on series gyrotrons. (19 th Joint Russian-German<br />
Workshop on ECRH and Gyrotrons, <strong>2007</strong>-07-18 to <strong>2007</strong>-07-24,<br />
Karlsruhe/Stuttgart/Garching).<br />
Garcia-Munoz, M., H.-U. Fahrbach, H. Zohm, J. Neuhauser,<br />
M. Maraschek, S. Günter, P. Martin, K. Sassenberg and
V. Igochine: MHD induced fast ion losses in ASDEX Upgrade.<br />
(DPG AMOP-Frühjahrstagung, <strong>2007</strong>-03-19 to <strong>2007</strong>-03-23,<br />
Düsseldorf).<br />
Garcia-Rosales, C., I. Lopez, N. Ordas, C. Adelhelm, M. Balden,<br />
S. Lindig, G. Pintsuk, M. Grattarola and C. Gualco: Ti-doped<br />
isotropic graphite for plasma facing components. (European<br />
Congress and Exhibition on Advanced Materials and Processes<br />
(EUROMAT <strong>2007</strong>), <strong>2007</strong>-09-10 to <strong>2007</strong>-09-13, Nürnberg).<br />
Garcia-Rosales, C., I. Lopez-Galilea, N. Ordas, C. Adelhelm,<br />
M. Balden, S. Lindig, G. Pintsuk, M. Grattarola and C. Gualco:<br />
Ti-doped isotropic graphite for plasma facing components.<br />
(13 th International Conference on Fusion Reactor Materials<br />
(ICFRM-13), <strong>2007</strong>-12-10 to <strong>2007</strong>-12-14, Nice).<br />
Geiger, J.: Stability analysis of Wendelstein 7-X configurations<br />
with increased mirror ratio. (Joint Conference of 17 th International<br />
Toki Conference on Physics of Flows and Turbulence<br />
in Plasmas and 16 th International Stellarator/Heliotron<br />
Workshop, <strong>2007</strong>-10-15 to <strong>2007</strong>-10-19, Ceratopia Toki, Gifu).<br />
Giannone, L.: Real time measurements for tokamak control.<br />
(12. Anwender- und Technologiekongress “VIP <strong>2007</strong>”,<br />
<strong>2007</strong>-10-10 to <strong>2007</strong>-10-11, Fürstenfeldbruck).<br />
Golubeva, A., Y. Gasparyan, M. Mayer and J. Roth: A new<br />
set-up for investigation of hydrogen ion driven permeation.<br />
(18 th International Conference on Ion-Surface Interactions,<br />
<strong>2007</strong>-08-24 to <strong>2007</strong>-08-28, Zvenigorod).<br />
Golubeva, A., M. Mayer and J. Roth: A new set-up for investigation<br />
of hydrogen ion driven permeation. (3 rd International<br />
Workshop “Interaction of Hydrogen Isotopes with Structural<br />
Materials”, <strong>2007</strong>-07-02 to <strong>2007</strong>-07-07, St. Petersburg).<br />
Greiche, A., W. Biel, R. Wolf and R. Burhenn: Absolute<br />
Intensitätskalibrierung des XUV/VUV Übersichts-Spektrometersystems<br />
HEXOS <strong>für</strong> Wendelstein 7-X. (DPG AMOP-<br />
Frühjahrstagung, <strong>2007</strong>-03-19 to <strong>2007</strong>-03-23, Düsseldorf).<br />
Greuner, H. and B. Böswirth: Results of HHF tests of W7-X<br />
target elements – the influence of degradation of heat transfer.<br />
(ITER Divertor Meeting, <strong>2007</strong>-11-07 to <strong>2007</strong>-11-09, Barcelona).<br />
Greuner, H., B. Böswirth, J. Boscary, P. Chaudhuri, J. Schlosser,<br />
T. Friedrich, A. Plankensteiner and R. Tivey: Cyclic Heat Load<br />
Testing of Improved CFC/Cu Bonding for the W7-X Divertor<br />
Targets. (13 th International Conference on Fusion Reactor<br />
Materials (ICFRM-13), <strong>2007</strong>-12-10 to <strong>2007</strong>-12-14, Nice).<br />
Greuner, H., B. Böswirth, J. Boscary, A. Plankensteiner,<br />
B. Schedler and R. Tivey: Testing of improved CFC/Cu<br />
Lectures<br />
156<br />
Bondings for the W7-X Divertor Targets. (13 th International<br />
Conference on Fusion Reactor Materials (ICFRM-13),<br />
<strong>2007</strong>-12-10 to <strong>2007</strong>-12-14, Nice).<br />
Grote, H., J. Kißlinger, H. Greuner, B. Streibl and O. Volzke:<br />
Vacuum Systems at Wendelstein 7-X. (Symposium on Vacuum<br />
based Science and Technology, <strong>2007</strong>-09-05 to <strong>2007</strong>-09-07,<br />
Greifswald).<br />
Gruber, O.: ASDEX Upgrade Technical Systems. (Southwestern<br />
<strong>Institut</strong>e of Physics (SWIP), <strong>2007</strong>-10-15, Chengdu).<br />
Gruber, O. and ASDEX Upgrade Team: ASDEX Upgrade:<br />
Status and Planning for 2008. (ASDEX Upgrade Programme<br />
Committee Meeting, <strong>2007</strong>-12-11, Garching).<br />
Gruber, O. and ASDEX Upgrade Team: Recent results on<br />
ASDEX Upgrade. (Southwestern <strong>Institut</strong>e of Physics (SWIP),<br />
<strong>2007</strong>-10-15, Chengdu).<br />
Gruber, O., J. Schweinzer and H. Zohm: Extension of ASDEX<br />
Upgrade Operation (action A10/I). (ASDEX Upgrade Programme<br />
Committee Meeting, <strong>2007</strong>-12-11, Garching).<br />
Grulke, O.: Struktur der Materie <strong>für</strong> Umweltwissenschaftler.<br />
(SS <strong>2007</strong>. Vorlesung, Universität Greifswald).<br />
Grulke, O., T. Windisch, V. Naulin and T. Klinger: Propagation<br />
turbulenter Strukturen in Driftwellenturbulenz. (DPG AMOP-<br />
Frühjahrstagung, <strong>2007</strong>-03-19 to <strong>2007</strong>-03-23, Düsseldorf).<br />
Günter, S.: Einführung in die <strong>Plasmaphysik</strong>. (WS 2006/<strong>2007</strong>.<br />
Vorlesung, Technische Universität München).<br />
Gurbich, A., I. Bogdanovic-Radovic, M. Chiari, C. Jeynes,<br />
M. Kokkoris, A. Ramos, M. Mayer, E. Rauhala, O. Schwerer,<br />
Shi Liqun and I. Vickridge: Status of the Problem of Nuclear<br />
Cross Section Data for IBA. (18 th International Conference<br />
on Ion Beam Analysis, <strong>2007</strong>-09-23 to <strong>2007</strong>-09-28, Hyderabad).<br />
Gusev, V. K., V. K. Alimov, I. I. Arkhipov, M. Balden, E. A. Denisov,<br />
A. E. Gorodetsky, A. A. Kurdumov, T. N. Kompaniec, V. M. Lebedev,<br />
N. V. Litunovstkii, I. V. Mazul, A. N. Novokhatsky, Y. V. Petrov,<br />
N. V. Sakharov, V. M. Sharapov, E. I. Terukov, I. N. Trapeznikova,<br />
J. Roth, A. P. Zakharov and R. K. Zalavutdinov: Recrystallized<br />
RGTi Graphite Application as the First Wall Material<br />
in Globus-M Spherical Tokamak. (13 th International<br />
Conference on Fusion Reactor Materials (ICFRM-13),<br />
<strong>2007</strong>-12-10 to <strong>2007</strong>-12-14, Nice).<br />
Hamacher, T.: Die Kernfusion in der Energieversorgung der<br />
Zukunft. (Deutsche Kälte-Klimatagung <strong>2007</strong>, <strong>2007</strong>-11-21 to<br />
<strong>2007</strong>-11-23, Hannover).
Hamacher, T.: Role of Nuclear Fusion in a future energy<br />
scenario. (<strong>IPP</strong> Summer University for Plasma Physics,<br />
<strong>2007</strong>-09-24 to <strong>2007</strong>-09-28, Greifswald).<br />
Hamacher, T.: Safety and Environmental Aspects. (<strong>IPP</strong><br />
Summer University for Plasma Physics, <strong>2007</strong>-09-24 to<br />
<strong>2007</strong>-09-28, Greifswald).<br />
Harhausen, J., C. Fuchs, A. Kallenbach, M. Wischmeier and<br />
ASDEX Upgrade Team: Verteilung der Zuflussdichte von<br />
Neutralteilchen in ASDEX Upgrade. (DPG AMOP-Frühjahrstagung,<br />
<strong>2007</strong>-03-19 to <strong>2007</strong>-03-23, Düsseldorf).<br />
Harting, D., D. Reiter, H. Frerichs and Y. Feng: Model extensions<br />
of the 3D edge plasma fluid Monte Carlo code EMC3.<br />
(DPG AMOP-Frühjahrstagung, <strong>2007</strong>-03-19 to <strong>2007</strong>-03-23,<br />
Düsseldorf).<br />
Hatzky, R.: A new concept for efficiently parallelizing PIC<br />
codes in plasma physics. (13 th ScicomP Conference (ScicomP13),<br />
<strong>2007</strong>-07-16 to <strong>2007</strong>-07-20, Garching).<br />
Hauff, T. and F. Jenko: Redistribution of energetic particles by<br />
background turbulence. (3 rd IAEA Technical Meeting on the<br />
Theory of Plasma Instabilties, <strong>2007</strong>-03-26 to <strong>2007</strong>-03-28, York).<br />
Heidinger, R., I. Danilov, A. Meier, A. Arnold, J. Flamm,<br />
M. Thumm, F. Leuterer, J. Stober and D. Wagner: Low<br />
power mm-wave transmission characteristics of a frequency<br />
tuneable double disk CVD-diamond window. (32 nd International<br />
Conference on Infrared and Millimeter Waves and<br />
the 15 th International Conference on Terahertz Electronics<br />
(IRMMW-THz <strong>2007</strong>), <strong>2007</strong>-09-02 to <strong>2007</strong>-09-07, Cardiff).<br />
Heilgeist, J., T. Soddemann and H. Richter: Algorithms for Job<br />
and Resource Discovery for the Meta-Scheduler of the DEISA<br />
Grid. (International Conference on Advanced Engineering<br />
Computing and Applications in Sciences (ADVCOMP <strong>2007</strong>),<br />
<strong>2007</strong>-11-04 to <strong>2007</strong>-11-09, Papeete, French Polynesia).<br />
Hein, B., A. Cardella, D. Hermann, F. Leher and J. Segl:<br />
Final manufacture of the outer vessel of the cryostat for<br />
Wendelstein 7-X. (8 th International Symposium on Fusion<br />
Nuclear Technology (ISFNT-8), <strong>2007</strong>-09-30 to <strong>2007</strong>-10-05,<br />
Heidelberg).<br />
Heinemann, B., M. Fröschle, R. Gutser, R. Nocentini, R. Riedl<br />
and P. Angostinetti: Design of the Half-Size ITER Extraction<br />
System for “ELISE”. (Coordinating Committee on Neutral<br />
Beams (CCNB-Meeting), <strong>2007</strong>-05-22 to <strong>2007</strong>-05-24, Culham).<br />
Heinemann, B., M. Fröschle, R. Gutser, R. Nocentini, R. Riedl,<br />
P. Angostinetti and T. Jiang: Design Status of “ELISE” Testbed.<br />
Lectures<br />
157<br />
(CCNB – Combined ITER Design and R&D Review and Coordination<br />
Meeting, <strong>2007</strong>-11-28 to <strong>2007</strong>-12-01, Ahmedabad).<br />
Heitmann, N.: Stochastic Model of the German Electricity<br />
System. (78. Sitzung der GOR Arbeitsgruppe “Praxis der Mathematischen<br />
Optimierung”, <strong>2007</strong>-04-19 to <strong>2007</strong>-04-20, Aachen).<br />
Helander, P.: On rapid rotation in stellarators. (Joint Conference<br />
of 17 th International Toki Conference on Physics of Flows and<br />
Turbulence in Plasmas and 16 th International Stellarator/Heliotron<br />
Workshop, <strong>2007</strong>-10-15 to <strong>2007</strong>-10-19, Ceratopia Toki, Gifu).<br />
Henderson, M. A., G. Saibene, T. Bonicelli, R. Chavan, D. Farina,<br />
D. Fasel, R. Heidinger, E. Poli, G. Ramponi, O. Sauter and<br />
H. Zohm: Interface Issues associated with the ITER ECH<br />
system. (4 th IAEA Technical Meeting on ECRH Physics and<br />
Technology for ITER, <strong>2007</strong>-06-06 to <strong>2007</strong>-06-08, Vienna).<br />
Hennig, C., T. Bluhm, P. Heimann, H. Kroiss, J. Maier,<br />
H. Riemann and M. Zilker: Investigation of data losses when<br />
using UDP communication. (6 th IAEA Technical Meeting on<br />
Control, Data Acquisition and Remote Participation, <strong>2007</strong>-06-04<br />
to <strong>2007</strong>-06-08, Inuyama).<br />
Hennig, C., A. Werner, M. Marquardt, T. Bluhm, P. Heimann,<br />
H. Kroiss, J. Maier, H. Riemann and M. Zilker: Continuous<br />
data acquisition with on-line analysis for the Wendelstein7-X<br />
magnetic diagnostics. (6 th IAEA Technical Meeting on Control,<br />
Data Acquisition and Remote Participation, <strong>2007</strong>-06-04 to<br />
<strong>2007</strong>-06-08, Inuyama).<br />
Hergenhahn, U.: Autoionisation von Molekülen und<br />
Clustern in Elektron-Elektron Koinzidenzexperimenten.<br />
(BESSY-Seminar, <strong>2007</strong>-06-12, Berlin).<br />
Hergenhahn, U.: Elektronenspektroskopie an freien Clustern.<br />
(Seminar Physikalische Chemie, <strong>2007</strong>-07-02, Freie Universität<br />
Berlin).<br />
Hergenhahn, U.: Interatomic/-molecular Coulombic Decay in<br />
Clusters: An Introduction. (Nanoscience Seminar, <strong>2007</strong>-08-30,<br />
Universität Bergen).<br />
Hergenhahn, U.: Photoelectron-Auger electron coincidence<br />
spectroscopy. (<strong>Institut</strong>e of Organic Chemistry and Biochemistry,<br />
Academy of the Sciences, <strong>2007</strong>-02-02, Prague).<br />
Hergenhahn, U.: Schwach gebundene Cluster: Elektronenspektroskopie<br />
und Autoionisation. (Clustertreffen <strong>2007</strong>,<br />
<strong>2007</strong>-09-23 to <strong>2007</strong>-09-28, Berlin-Spandau).<br />
Hergenhahn, U., S. Barth, V. Ulrich, S. Marburger, M. Lundwall,<br />
G. Öhrwall and O. Björneholm: Effiziente Autoionisation
schwach gebundener Cluster durch Interatomaren Coulomb-<br />
Zerfall (ICD). (DPG AMOP-Frühjahrstagung, <strong>2007</strong>-03-19<br />
to <strong>2007</strong>-03-23, Düsseldorf).<br />
Herrmann, A.: Power and particle exhaust measurements.<br />
(International Workshop on Burning Plasma Diagnostics,<br />
<strong>2007</strong>-09-24 to <strong>2007</strong>-09-28, Varenna).<br />
Herrmann, A., M. Balden and H. Bolt: Tungsten fibre reinforced<br />
copper for high-temperature heat sink material for fusion<br />
application. (16. Symposium: Verbundwerkstoffe und Werkstoffverbunde,<br />
DGM, <strong>2007</strong>-03-14 to <strong>2007</strong>-03-16, Bremen).<br />
Herrmann, A., M. Balden, A. Brendel and H. Bolt: Interfacial<br />
characterisation of tungsten fibre reinforced copper<br />
for high-temperature heat sink material for fusion application.<br />
(European Congress and Exhibition on Advanced Materials<br />
and Processes (EUROMAT <strong>2007</strong>), <strong>2007</strong>-09-10 to <strong>2007</strong>-09-13,<br />
Nürnberg).<br />
Herrmann, A., K. Schmid, M. Balden and H. Bolt: Interfacial<br />
optimization of tungsten fibre reinforced copper for<br />
high-temperature heat sink material for fusion application.<br />
(13 th International Conference on Fusion Reactor Materials<br />
(ICFRM-13), <strong>2007</strong>-12-10 to <strong>2007</strong>-12-14, Nice).<br />
Herrmann, J.: Challenges and Opportunities of an Interconnected<br />
European and Russian Electricity Network. (9 th IAEE<br />
European Energy Conference – Energy Markets and Sustainability<br />
in a Larger Europe, <strong>2007</strong>-06-10 to <strong>2007</strong>-06-13,<br />
Florence).<br />
Hobirk, J., E. Joffrin and EFDA JET Contributors: Progress<br />
in documentation of the hybrid scenario in JET. (49 th <strong>Annual</strong><br />
Meeting of the Division of Plasma Physics, <strong>2007</strong>-11-12 to<br />
<strong>2007</strong>-11-16, Orlando, FL).<br />
Hölzl, M., S. Günter, Q. Yu and K. Lackner: Numerical modeling<br />
of diffusive heat transport across magnetic islands and highly<br />
stochastic layers. (Biennial Workshop “Stochasticity in Fusion<br />
Plasmas” (SFP <strong>2007</strong>), <strong>2007</strong>-03-05 to <strong>2007</strong>-03-07, Jülich).<br />
Hopf, C., M. Schlüter and W. Jacob: Chemical sputtering of<br />
carbon films by argon ions and molecular oxygen between<br />
110 and 850 K. (Physique des Interactions Ioniques et<br />
Moleculaires, <strong>2007</strong>-06-25, Universite de Provence, Marseille).<br />
Horton, L. D.: Physics Issues for DEMO. (Carolus Magnus<br />
Summer School on Plasma and Fusion Energy Physics,<br />
<strong>2007</strong>-09-03 to <strong>2007</strong>-09-14, Bad Honnef).<br />
Horton, L. D.: Reactor (Physics) Concepts. (Carolus Magnus<br />
Summer School, <strong>2007</strong>-09-03 to <strong>2007</strong>-09-14, Bad Honnef).<br />
Lectures<br />
158<br />
Hoshino, K., A. Hatayama, D. Coster, X. Bonnin, R. Schneider,<br />
H. Kawashima, N. Asakura and Y. Suzuki: Benchmarking<br />
kinetic and fluid neutral models with drift effects. (11 th International<br />
Workshop on Plasma Edge Theory in Fusion Devices<br />
(PET 11), <strong>2007</strong>-05-23 to <strong>2007</strong>-05-25, Takayama-city).<br />
Igitkhanov, Y., M. Kobyashi, S. Masuzaki, T. Morisaki,<br />
B. J. Peterson, M. Shoji, H. Yamada, K. Kawahata, S. Sudo<br />
and O. Motojima: Momentum removal from plasma flow in the<br />
Helical island divertor. (11 th International Workshop on<br />
Plasma Edge Theory in Fusion Devices (PET 11), <strong>2007</strong>-05-23<br />
to <strong>2007</strong>-05-25, Takayama-city).<br />
Igitkhanov, Y., A. Sagara, B. Peterson, S. Sudo and O. Motojima:<br />
Impurity Control by small Pellet Injection at the Plasma<br />
Edge of a Helical Device. (11 th International Workshop on<br />
Plasma Edge Theory in Fusion Devices (PET 11), <strong>2007</strong>-05-23<br />
to <strong>2007</strong>-05-25, Takayama-city).<br />
Igochine, V.: RWM rotation experiments in RFX-mod. (RFXmod<br />
Programme Workshop, <strong>2007</strong>-12-13 to <strong>2007</strong>-12-14, Padova).<br />
Igochine, V., O. Dumbrajs, H. Zohm and A. Flaws: Stochastic<br />
sawtooth reconnection in ASDEX Upgrade. (Biennial<br />
Workshop “Stochasticity in Fusion Plasmas” (SFP <strong>2007</strong>),<br />
<strong>2007</strong>-03-05 to <strong>2007</strong>-03-07, Jülich).<br />
Jacob, W.: Materials Research at <strong>IPP</strong>. (Physique des Interactions<br />
Ioniques et Moleculaires, <strong>2007</strong>-06-26, Universite de<br />
Provence, Marseille).<br />
Jacob, W., C. Hopf and M. Schlüter: Chemical sputtering of<br />
carbon films by argon ions and molecular oxygen between<br />
110 and 850 K. (17 th International Vacuum Congress (IVC-17),<br />
13 th International Conference on Surface Science (ICSS-13),<br />
International Conference on Nano Science and Technology<br />
(ICN+T <strong>2007</strong>), <strong>2007</strong>-07-02 to <strong>2007</strong>-07-06, Stockholm).<br />
Jacob, W., M. Schlüter, C. Hopf and T. Schwarz-Selinger:<br />
Chemische Zerstäubung durch simultanen Beschuss von<br />
Kohlenstoff mit Argonionen und molekularem Sauerstoff.<br />
(14. Erfahrungsaustausch Oberflächentechnologie mit Plasmaund<br />
Ionenstrahlprozessen, <strong>2007</strong>-03-13 to <strong>2007</strong>-03-15,<br />
Mühlleithen).<br />
Jakubowski, M., K.-H. Finken, M. Lehnen, O. Schmitz, B. Unterberg<br />
and R. Wolf: Influence of Dynamic Ergodic Divertor on heat<br />
and particle transport in TEXTOR. (Meeting of Polish<br />
EURATOM Association, <strong>2007</strong>-09-17 to <strong>2007</strong>-09-21, Kudowa).<br />
Jenko, F.: Theory and simulation on transport barriers.<br />
(11 th IAEA TM on H-mode Physics and Transport Barriers,<br />
<strong>2007</strong>-09-26 to <strong>2007</strong>-09-28, Tsukuba).
Jenzsch, H., A. Cardella, J. Reich, W. Gardebrecht and<br />
M. Bednarek: Final Design and Manufacture of the Cryolegs<br />
to W7-X Superconducting Coil Magnet and Support System.<br />
(8 th International Symposium on Fusion Nuclear Technology<br />
(ISFNT-8), <strong>2007</strong>-09-30 to <strong>2007</strong>-10-05, Heidelberg).<br />
Jüttner, B., S. Noack, A. Versteegh and G. Fußmann: Long-<br />
Living Plasmoids from a Water Discharge at Atmospheric<br />
Pressure. (28 th International Conference on Phenomena in<br />
Ionized Gases (ICPIG), <strong>2007</strong>-07-15 to <strong>2007</strong>-07-20, Prague).<br />
Kallenbach, A.: Die Eigenschaften des Randschichtplasma –<br />
ein Schlüsselthema der kontrollierten Kernfusion. (Physikalisches<br />
Kolloquium, <strong>2007</strong>-04-23, Universität Augsburg).<br />
Kallenbach, A.: Einführung in die Plasmaspektroskopie.<br />
(SS <strong>2007</strong>. Vorlesung, Universität Augsburg).<br />
Kasparek, W., M. Petelin, D. Shchegolkov, V. Erckmann,<br />
B. Plaum, A. Bruschi and ECRH Groups at <strong>IPP</strong>, FZK and IPF:<br />
FADIS, a fast switch and combiner for high-power millimetre<br />
wave beams. (4 th IAEA Technical Meeting on ECRH<br />
Physics and Technology for ITER, <strong>2007</strong>-06-06 to <strong>2007</strong>-06-08,<br />
Vienna).<br />
Kaufmann, M.: Einführung in die <strong>Plasmaphysik</strong> und Fusionsforschung<br />
I. (WS 2006/<strong>2007</strong>. Vorlesung, Universität Bayreuth).<br />
Kaufmann, M.: Einführung in die <strong>Plasmaphysik</strong> und Fusionsforschung<br />
II. (SS <strong>2007</strong>. Vorlesung, Universität Bayreuth).<br />
Kervalishvili, G. N., P. Kleiber, R. Schneider, B. D. Scott,<br />
O. Grulke and T. Windisch: Intermittent turbulence in the<br />
linear VINETA device. (11 th International Workshop on Plasma<br />
Edge Theory in Fusion Devices (PET 11), <strong>2007</strong>-05-23 to<br />
<strong>2007</strong>-05-25, Takayama-city).<br />
Kleiber, R., R. Hatzky and A. Mishchenko: Global gyrokinetic<br />
simulations for stellarators. (Joint Conference of 17 th International<br />
Toki Conference on Physics of Flows and Turbulence<br />
in Plasmas and 16 th International Stellarator/Heliotron<br />
Workshop, <strong>2007</strong>-10-15 to <strong>2007</strong>-10-19, Ceratopia Toki, Gifu).<br />
Kobayashi, M., Y. Feng, S. Masuzaki, T. Morisaki, S. Morita,<br />
H. Yamada and LHD Experimental Group: Modelling of impurity<br />
transport in ergodic layer of LHD. (11 th International<br />
Workshop on Plasma Edge Theory in Fusion Devices (PET 11),<br />
<strong>2007</strong>-05-23 to <strong>2007</strong>-05-25, Takayama-city).<br />
Koch, F., S. Köppl and H. Bolt: Self Passivating W-based<br />
Alloys as Plasma Facing Material. (13 th International Conference<br />
on Fusion Reactor Materials (ICFRM-13), <strong>2007</strong>-12-10<br />
to <strong>2007</strong>-12-14, Nice).<br />
Lectures<br />
159<br />
König, R., R. Burhenn, J. Cantarini, K. Grosser, H. J. Hartfuß,<br />
D. Hildebrandt, M. Hirsch, G. Kocsis, P. Kornejew, M. Laux,<br />
E. Pasch, S. Recsei, J. Sachtleben, J. Sarközi, W. Schneider,<br />
V. Szabó, H. Thomsen, A. Weller, A. Werner, R. Wolf, M. Y. Ye,<br />
D. Zhang and S. Zoletnik: Diagnostic Developments for<br />
Quasi-Continuous Operation of the W7-X Stellarator. (Inter<br />
of Plasmas, <strong>2007</strong>-10-16 to <strong>2007</strong>-10-19, Greifswald).<br />
König, R., J. Cantarini, K. Grosser, D. Hildebrandt, M. Hirsch,<br />
G. Kocsis, P. Kornejew, M. Laux, E. Pasch, S. Recsei, V. Szabó,<br />
H. Thomsen, A. Weller, A. Werner, R. Wolf, M. Ye and S. Zoletnik:<br />
Diagnostic Developments for Quasi-Continuous Operation<br />
of the Wendelstein 7-X Stellarator. (PLASMA <strong>2007</strong> – International<br />
Conference on Research and Applications of Plasmas<br />
combined with the 4 th German-Polish Conference on Plasma<br />
Diagnostics for Fusion and Applications and the 6 th French-<br />
Polish Seminar on Thermal Plasma in Space and Laboratory,<br />
<strong>2007</strong>-10-16 to <strong>2007</strong>-10-19, Greifswald).<br />
Kolesnichenko, Y. I., V. V. Lutsenko, A. Weller, A. Werner,<br />
Y. Yakovenko, J. Geiger and O. P. Fesenyuk: Modelling of lowfrequency<br />
alfvénic activity in Wendelstein 7-AS. (34 th European<br />
Physical Society Conference on Plasma Physics, <strong>2007</strong>-07-02<br />
to <strong>2007</strong>-07-06, Warsaw).<br />
Kolesnichenko, Y., V. V. Lutsenko, A. Weller, A. Werner, Y. Yakovenko<br />
and J. Geiger: Low Frequency Alfvén Instabilities in Stellarators:<br />
Peculiarities and the Use for Diagnostics. (10 th IAEA<br />
Technical Meeting on Energetic Particles in Magnetic Confinement<br />
Systems, <strong>2007</strong>-10-08 to <strong>2007</strong>-10-10, Kloster Seeon).<br />
Kost, F. and C. Linsmeier: First results from beryllium on carbon.<br />
(EFDA SEWG Meeting on Mixed Materials, <strong>2007</strong>-07-09 to<br />
<strong>2007</strong>-07-10, JET, Culham).<br />
Kost, F. and C. Linsmeier: Reactions in the Ternary Be-C-W<br />
System. (EFDA SEWG Meeting on Mixed Materials,<br />
<strong>2007</strong>-07-09 to <strong>2007</strong>-07-10, JET, Culham).<br />
Kraus, W.: Long pulse operation of the <strong>IPP</strong> RF source. (Coordinating<br />
Committee on Neutral Beams (CCNB-Meeting),<br />
<strong>2007</strong>-05-22 to <strong>2007</strong>-05-24, Culham).<br />
Kraus, W. and NBI Team: Overview on the RF Source Development<br />
Programme at <strong>IPP</strong>. (CCNB – Combined ITER Design<br />
and R&D Review and Co-ordination Meeting, <strong>2007</strong>-11-28<br />
to <strong>2007</strong>-12-01, Ahmedabad).<br />
Kraus, W., R. Riedl, H.-D. Falter, U. Fantz, P. Franzen,<br />
B. Heinemann, M. Fröschle, C. Martens, P. McNeely, M. Berger<br />
and E. Speth: Long pulse large area beam extraction with an<br />
RF driven H - /D - source. (12 th International Conference on<br />
Ion Sources (ICIS <strong>2007</strong>), <strong>2007</strong>-08-26 to <strong>2007</strong>-08-31, Jeju).
Krieger, K.: Plasma-Wall interaction basics for metallic materials.<br />
(15 th European Fusion Physics Workshop, <strong>2007</strong>-12-03<br />
to <strong>2007</strong>-12-05, Prague).<br />
Krieger, K.: Plasma Wall Interaction and First Wall Materials.<br />
(<strong>IPP</strong> Summer University for Plasma Physics, <strong>2007</strong>-09-24 to<br />
<strong>2007</strong>-09-28, Greifswald).<br />
Krieger, K., I. Bizyukov, F. Kost, H. Lee, C. Linsmeier, M. Reinelt<br />
and <strong>IPP</strong> PWI Group: Investigation of mixed material surface<br />
processes and multi-species ion bombardment. (1 st IAEA<br />
Research Co-ordination Meeting on Data for Surface Composition<br />
Dynamics relevant to Erosion Processes, <strong>2007</strong>-10-17<br />
to <strong>2007</strong>-10-19, Vienna).<br />
Krieger, K., M. Stamp, S. Brezinsek, H. G. Esser, S. Jachmich,<br />
A. Kreter, P. Mertens, V. Philipps, P. Sundelin and JET EFDA<br />
Contributors: Be migration after Be evaporation in JET.<br />
(JET Task Force E Migration Workshop, <strong>2007</strong>-03-09, Culham).<br />
Krieger, K., M. Stamp, S. Brezinsek, H. Esser, S. Jachmich,<br />
A. Kreter, S. Menmuir, P. Mertens, V. Philipps, P. Sundelin and<br />
EFDA JET Contributors: Evolution of Be migration after Be<br />
evaporation in the JET tokamak. (34 th Conference on Plasma<br />
Physics of the European Physical Society, <strong>2007</strong>-07-02 to<br />
<strong>2007</strong>-07-06, Warsaw).<br />
Krychowiak, M., P. Mertens, B. Schweer, S. Brezinsek, R. König,<br />
O. Schmitz, M. Brix, T. Klinger and U. Samm: LIF measurements<br />
on an atomic helium beam in the edge of a fusion plasma –<br />
possible derivation of the electron density. (PLASMA <strong>2007</strong> –<br />
International Conference on Research and Applications of<br />
Plasmas combined with the 4 th German-Polish Conference<br />
on Plasma Diagnostics for Fusion and Applications and the<br />
6 th French-Polish Seminar on Thermal Plasma in Space and<br />
Laboratory, <strong>2007</strong>-10-16 to <strong>2007</strong>-10-19, Greifswald).<br />
Kus, A., E. Ascasibar, A. Dinklage, J. H. Harris, S. Okamura,<br />
R. Preuss, F. Sano, U. Stroth, J. Talmadge and H. Yamada: Cluster<br />
analysis of the International Stellarator Confinement Database.<br />
(PLASMA <strong>2007</strong> – International Conference on Research<br />
and Applications of Plasmas combined with the 4 th German-<br />
Polish Conference on Plasma Diagnostics for Fusion and<br />
Applications and the 6 th French-Polish Seminar on Thermal<br />
Plasma in Space and Laboratory, <strong>2007</strong>-10-16 to <strong>2007</strong>-10-19,<br />
Greifswald).<br />
Kus, A., A. Krüger, A. Dinklage, T. Bluhm, C. G. Hanke, G. Kühner,<br />
A. Werner, C. Hennig, J. Geiger, M. Lewerentz, Yu. Turkin and<br />
W7-X Team: Unified Software Repositories for Wendelstein 7-X:<br />
Workflow Elements for Fusion Software Development. (6 th IAEA<br />
TM on Control, Data Acquisition, and Remote Participation<br />
for Fusion Research, <strong>2007</strong>-06-04 to <strong>2007</strong>-06-08, Inuyama).<br />
Lectures<br />
160<br />
Lang, P. T.: Pellet triggering as a tool to understand ELM<br />
physics. (10 th ITPA MHD Topical Group Meeting, <strong>2007</strong>-10-12,<br />
Garching).<br />
Lang, P. T.: Status of pellet pacing ELM control and prospects<br />
for ITER. (Joint ITPA Meeting of Pedestal and Divertor &<br />
SOL Topical Groups, <strong>2007</strong>-05-07, Garching).<br />
Lang, P. T., L. Fattorini, L. D. Horton, A. Kallenbach, K. Lackner,<br />
W. Suttrop and ASDEX Upgrade Team: Pellet perturbations<br />
for probing threshold conditions and investigating onset<br />
dynamics of paced ELMs. (11 th IAEA TM on H-mode Physics<br />
and Transport Barriers, <strong>2007</strong>-09-26 to <strong>2007</strong>-09-28, Tsukuba).<br />
Lang, P. T., K. Lackner, L. Fattorini, A. Kallenbach, M. Maraschek,<br />
J. Neuhauser, W. Suttrop and ASDEX Upgrade Team: Investigations<br />
of pellet triggered MHD events in ASDEX Upgrade.<br />
(10 th Workshop on the Electric Fields, Structures, and Relaxation<br />
in Plasmas, <strong>2007</strong>-07-08 to <strong>2007</strong>-07-09, Warsaw).<br />
Laqua, H., M. Otte, Y. Podoba, S. Marsen, WEGA-Team,<br />
J. Preinhaelter, J. Urban and E. Holzhauer: Direct Measurement<br />
of the Electron Bernstein Wave Heating and Current Drive<br />
at the WEGA Stellarator. (49 th <strong>Annual</strong> Meeting of the Division<br />
of Plasma Physics, <strong>2007</strong>-11-12 to <strong>2007</strong>-11-16, Orlando, FL).<br />
Laqua, H. P.: Electron Bernstein Wave Heating and Current<br />
Drive at the WEGA Stellarator. (19 th Joint Russian-German<br />
Workshop on ECRH and Gyrotrons, <strong>2007</strong>-07-18 to <strong>2007</strong>-07-24,<br />
Garching).<br />
Laqua, H. P.: Electron Cyclotron Resonance Heating, Ion<br />
Cyclotron Resonance Heating, Lower Hybrid Heating.<br />
(International Summer School on Fusion Technologies,<br />
<strong>2007</strong>-09-03 to <strong>2007</strong>-09-14, Karlsruhe).<br />
Laqua, H. P.: Intensive Mikrowellen im Plasma. (Kolloquium,<br />
<strong>2007</strong>-05-03, Greifswald).<br />
Laqua, H. P.: Intensive Mikrowellen im Plasma. (Kolloquium,<br />
<strong>Institut</strong> <strong>für</strong> Hochleistungsimpuls- und Mikrowellentechnik,<br />
<strong>2007</strong>-11-22, Forschungszentrum Karlsruhe).<br />
Laqua, H. P.: The stellarator facility Wendelstein 7-X.<br />
(International Summer School on Fusion Technologies,<br />
<strong>2007</strong>-09-03 to <strong>2007</strong>-09-14, Karlsruhe).<br />
Laqua, H. P.: The transition into steady state W7-X operation<br />
by ECCD and ECRH. (15 th European Fusion Physics<br />
Workshop, <strong>2007</strong>-12-03 to <strong>2007</strong>-12-05, Prague).<br />
Laqua, H. P., E. Holzhauer, S. Marsen, M. Otte, Y. Y. Podoba,<br />
M. Schubert and G. B. Warr: Electron Cyclotron Wave Experi-
ments at the WEGA Stellarator. (34 th European Physical Society<br />
Conference on Plasma Physics, <strong>2007</strong>-07-02 to <strong>2007</strong>-07-06,<br />
Warsaw).<br />
Lauber, P., S. Günter, H. L. Berk, M. Brüdgam, M. Garcia<br />
Munoz and ASDEX Upgrade Team: Damping and drive of low<br />
frequency modes in tokamak plasmas. (10 th IAEA Technical<br />
Meeting on Energetic Particles, <strong>2007</strong>-10-08 to <strong>2007</strong>-10-10,<br />
Kloster Seeon).<br />
Lauber, P., S. Günter, S. da Graça, A. Könies, S. D. Pinches<br />
and M. Brüdgam: Damping rates of global Alfvén waves in<br />
tokamaks. (3 rd IAEA Technical Meeting on the Theory of<br />
Plasma Instabilties, <strong>2007</strong>-03-26 to <strong>2007</strong>-03-28, York).<br />
Lauber, P., S. Günter, S. da Graça, A. Könies, S. D. Pinches<br />
and M. Brüdgam: Damping rates of global Alfvén waves in<br />
tokamaks. (3 rd IAEA Technical Meeting on the Theory of<br />
Plasma Instabilties, <strong>2007</strong>-03-26 to <strong>2007</strong>-03-28, York).<br />
Lechte, C., E. Holzhauer, G. Conway, W. Kasparek and U. Stroth:<br />
Simulation von Doppler-Reflektometrie in turbulenten Plasmen<br />
mit Finite Difference Time Domain Codes. (DPG AMOP-<br />
Frühjahrstagung, <strong>2007</strong>-03-19 to <strong>2007</strong>-03-23, Düsseldorf).<br />
Lederer, H.: DEISA: on the way towards an integrated European<br />
HPC ecosystem. (13th ScicomP Conference (ScicomP13),<br />
<strong>2007</strong>-07-16 to <strong>2007</strong>-07-20, Garching).<br />
Lederer, H.: Erste Erfahrungen mit dem weltweit ersten<br />
BlueGene/P System. (ZKI-Tagung, <strong>2007</strong>-10-25, GWDG<br />
Göttingen).<br />
Lederer, H.: Garching BlueGene/P: First Application Performance<br />
Results. (BlueGene Consortium Meeting, <strong>2007</strong>-11-13,<br />
Reno, NV).<br />
Lederer, H., R. Tisma, R. Hatzky, A. Bottino and F. Jenko:<br />
Application Enabling in DEISA: Hyperscaling of Turbulence<br />
Codes Supporting ITER. (Parallel Computing (ParCo),<br />
<strong>2007</strong>-09-03 to <strong>2007</strong>-09-07, Jülich).<br />
Lederer, H., R. Tisma, R. Hatzky, A. Bottino and F. Jenko:<br />
Application Enabling in DEISA: Petascaling of Plasma<br />
Turbulence Codes. (Parallel Computing (ParCo), <strong>2007</strong>-09-03<br />
to <strong>2007</strong>-09-07, Jülich).<br />
Lederer, H., R. Tisma, R. Hatzky, A. Bottino and F. Jenko: Towards<br />
Petascale Computing in Support of ITER. (13 th ScicomP<br />
Conference (ScicomP13), <strong>2007</strong>-07-16 to <strong>2007</strong>-07-20, Garching).<br />
Leuterer, F., H. Schütz, J. Stober and D. Wagner: Overview<br />
of the ASDEX Upgrade ECRH system performance in 1998<br />
Lectures<br />
161<br />
to <strong>2007</strong>. (19 th Russian-German STC Workshop on ECRH and<br />
Gyrotrons, <strong>2007</strong>-07-23, Garching).<br />
Levchuk, D.: Permeation barriers for hydrogen applications.<br />
(9 th International Workshop on Plasma-Based Ion Implantation<br />
& Deposition (PBIID-07), <strong>2007</strong>-09-02 to <strong>2007</strong>-09-06,<br />
Leipzig).<br />
Levchuk, D., K. Ertl, H. Maier and H. Bolt: Radiation damage<br />
effect on the performance of tritium permeation barriers.<br />
(8 th International Symposium on Fusion Nuclear Technology<br />
(ISFNT-8), <strong>2007</strong>-09-30 to <strong>2007</strong>-10-05, Heidelberg).<br />
Linke, J., T. Hirai, P. Mertens, B. Schweer and H. Altmann:<br />
Status of the ITER-like JET divertor. (ITER Divertor Meeting,<br />
<strong>2007</strong>-11-07 to <strong>2007</strong>-11-09, Barcelona).<br />
Linsmeier, C.: The European Integrated Project on Materials for<br />
Extreme Environments. (European Congress and Exhibition<br />
on Advanced Materials and Processes (EUROMAT <strong>2007</strong>),<br />
<strong>2007</strong>-09-10 to <strong>2007</strong>-09-13, Nürnberg).<br />
Linsmeier, C.: Ion Scattering Spectroscopy. (Fritz-Haber-<br />
<strong>Institut</strong>, <strong>2007</strong>-01-12, Berlin).<br />
Linsmeier, C.: Materials issues in fusion and relation to other<br />
applications. (Jahrestagung Kerntechnik <strong>2007</strong>, <strong>2007</strong>-05-24<br />
to <strong>2007</strong>-05-24, Karlsruhe).<br />
Linsmeier, C.: New materials for extreme environments in<br />
fusion applications. (Schwerpunktseminar Schwerpunkt<br />
Ionen- und <strong>Plasmaphysik</strong>/Angwandte Physik, <strong>2007</strong>-05-14<br />
to <strong>2007</strong>-05-14, Universität Innsbruck).<br />
Linsmeier, C.: Oberflächenreaktionen auf Beryllium aus der<br />
Perspektive der Kernfusion. (Humboldt-Universität, <strong>2007</strong>-01-11,<br />
Berlin).<br />
Linsmeier, C.: Overview on the ExtreMat project. (2 nd KMM-<br />
NoE Integration Conference, <strong>2007</strong>-10-24 to <strong>2007</strong>-10-25,<br />
Vienna).<br />
Linsmeier, C.: Surface Chemistry of Fusion First Wall<br />
Materials. (Kolloquium Physikalische Chemie, <strong>2007</strong>-07-19,<br />
Universität München).<br />
Linsmeier, C., H. Bolt, M. Balden, A. Brendel, K. Ertl,<br />
F. Koch, F. Kost, D. Levchuk, H. Maier, J. Roth, K. Schmid<br />
and A. Wiltner: Materialien in der Kernfusion: Plasmabelastung<br />
und chemisches Verhalten. (16. Diskussionstagung<br />
Anorganisch-Technische Chemie, <strong>2007</strong>-02-21 to <strong>2007</strong>-02-22,<br />
Dechema, Frankfurt).
Linsmeier, C., H. Bolt, M. Balden, A. Brendel, F. Koch, D. Levchuk,<br />
H. Maier, K. Ertl, J. Roth, A. Wiltner, F. Kost and K. Schmid:<br />
Neue Materialien <strong>für</strong> den Einsatz unter extremen Anforderungen<br />
in der Kernfusion. (ISC-Seminar, <strong>2007</strong>-02-02,<br />
Fraunhofer-<strong>Institut</strong> <strong>für</strong> Silicatforschung, Würzburg).<br />
Loarer, T., J. Roth, S. Brezinsek, A. Kirschner, M. Mayer, R. Neu,<br />
V. Philipps, V. Rohde, M. Rubel and E. Tsitrone: Tritium<br />
Intentory in ITER: Laboratory data and extrapolation from<br />
tokamaks. (6 th Meeting of Contact Persons of the EU-PWI<br />
Task Force, <strong>2007</strong>-10-29 to <strong>2007</strong>-10-31, Madrid).<br />
Lopez-Galilea, I., N. Ordas, C. Garcia-Rosales and S. Lindig:<br />
Improvement of Thermal Shock Resistance of Isotropic Graphite<br />
by Ti-doping. (13 th International Conference on Fusion Reactor<br />
Materials (ICRFM-13), <strong>2007</strong>-12-10 to <strong>2007</strong>-12-14, Nice).<br />
Lunt, T. and G. Fußmann: Messungen mit Laserinduzierter<br />
Fluoreszenz in der Nähe eines absorbierenden Targets.<br />
(DPG AMOP-Frühjahrstagung, <strong>2007</strong>-03-19 to <strong>2007</strong>-03-23,<br />
Düsseldorf).<br />
Lutsenko, V. V., Y. Kolesnichenko, A. Weller, A. Werner,<br />
H. Wobig and A. V. Tykhyy: Effect of the Radial Electric Field<br />
on the Confinement of Fast Ions in Optimized Stellarators.<br />
(10 th IAEA Technical Meeting on Energetic Particles in<br />
Magnetic Confinement Systems, <strong>2007</strong>-10-08 to <strong>2007</strong>-10-10,<br />
Kloster Seeon).<br />
Mahdizadeh, N., F. Greiner, T. Happel, A. Kendl, M. Ramisch,<br />
B. Scott and U. Stroth: Dreidimensionale Dynamik von Driftwellenturbulenz.<br />
(DPG AMOP-Frühjahrstagung, <strong>2007</strong>-03-19<br />
to <strong>2007</strong>-03-23, Düsseldorf).<br />
Maisberger, F., U. Fantz and NNBI-Team: Messung zur Plasmahomogenität<br />
an HF-Quellen zur Erzeugung negativer Ionen.<br />
(DPG AMOP-Frühjahrstagung, <strong>2007</strong>-03-19 to <strong>2007</strong>-03-23,<br />
Düsseldorf).<br />
Manini, A., K. Behler, L. Giannone, F. Leuterer, M. Maraschek,<br />
F. Monaco, G. Neu, G. Raupp, A. Sips, J. Stober, W. Suttrop,<br />
W. Treutterer, D. Wagner, H. Zohm, S. Cirant, F. Gandini,<br />
G. D’Antona, H. Bindslev, F. Leipold and F. Meo: Implementation<br />
of a feedback system for MHD control with ECRH using<br />
real time fast steerable mirrors. (19 th Russian-German STC<br />
Workshop on ECRH and Gyrotrons, <strong>2007</strong>-07-23, Garching).<br />
Manini, A., G. Gantenbein, M. Maraschek, N. Hicks, F. Leuterer,<br />
R. Neu, J. Stober, W. Suttrop, D. Wagner, H. Zohm and<br />
ASDEX Upgrade Team: Plasma stability enhancement using<br />
EC-RH/CD in ASDEX Upgrade. (4 th IAEA Technical Meeting<br />
on ECRH Physics and Technology for ITER, <strong>2007</strong>-06-06 to<br />
<strong>2007</strong>-06-08, Vienna).<br />
Lectures<br />
162<br />
Manini, A., M. Maraschek, G. Gantenbein, Q. Yu, H. Zohm,<br />
S. Günter, F. Leuterer and ASDEX Upgrade Team: Increasing<br />
NTM stabilization efficiency using modulated ECCD in ASDEX<br />
Upgrade. (17 th Topical Conference on Radio Frequency<br />
Power in Plasmas, <strong>2007</strong>-05-07 to <strong>2007</strong>-05-09, Clearwater, FL).<br />
Mantsinen, M. J., R. Bilato, Vl. Bobkov, L.-G. Eriksson,<br />
H.-U. Fahrbach, M. Garcia-Muñoz, J.-M. Noterdaeme,<br />
W. Schneider and ASDEX Upgrade Team: Analysis of ICRFaccelerated<br />
ions in ASDEX Upgrade. (17 th Topical Conference<br />
on Radio Frequency Power in Plasmas, <strong>2007</strong>-05-07 to<br />
<strong>2007</strong>-05-09, Clearwater, FL).<br />
Mantsinen, M. J. and JET-EFDA Contributors: Modification<br />
of sawtooth oscillations with ICRF waves in the JET<br />
tokamak. (17 th Topical Conference on Radio Frequency Power<br />
in Plasmas, <strong>2007</strong>-05-07 to <strong>2007</strong>-05-09, Clearwater, FL).<br />
Manz, P., V. Naulin, R. Ramisch, B. Scott and U. Stroth: Experimentelle<br />
Untersuchung des nichtlinearen Energietransfers<br />
in zweidimensionaler Plasmaturbulenz. (DPG AMOP-Frühjahrstagung,<br />
<strong>2007</strong>-03-19 to <strong>2007</strong>-03-23, Düsseldorf).<br />
Marsen, S., M. Otte, M. Schubert and F. Wagner: Zur Struktur<br />
turbulenter Fluktuationen am Stellarator WEGA. (DPG AMOP-<br />
Frühjahrstagung, <strong>2007</strong>-03-19 to <strong>2007</strong>-03-23, Düsseldorf).<br />
Marsen, S., M. Otte and F. Wagner: Structure of Turbulence<br />
in the WEGA Stellarator. (7 th International Workshop on<br />
Electrical Probes in Magnetized Plasmas, <strong>2007</strong>-07-22 to<br />
<strong>2007</strong>-07-25, Prague).<br />
Marushchenko, N. B., C. D. Beidler, V. Erckmann, H. Maaßberg<br />
and Yu. Turkin: ECCD scenarios for different configurations<br />
of the W7-X Stellarator. (Joint Conference of the 17 th International<br />
Toki Conference on Physics of Flows and Turbulence<br />
in Plasmas (ITC) and 16 th International Stellarator/Heliotron<br />
Workshop, <strong>2007</strong>-10-15 to <strong>2007</strong>-10-19, Ceratopia Toki, Gifu).<br />
Marushchenko, N. B., V. Erckmann, H. P. Laqua, H. Maaßberg<br />
and Yu. Turkin: Analysis of ECCD scenarios for different<br />
configurations of the W7-X Stellarator. (19 th Joint Russian-<br />
German Workshop on ECRH and Gyrotrons, <strong>2007</strong>-07-19 to<br />
<strong>2007</strong>-07-24, Garching).<br />
Marushchenko, N. B., V. Erckmann, H. P. Laqua, H. Maaßberg<br />
and Y. Turkin: Calculations of ECCD for W7-X & ITER.<br />
(Theory Meeting Sellin, <strong>2007</strong>-11-19 to <strong>2007</strong>-11-23, Sellin).<br />
Marushchenko, N. B., H. Maaßberg and Y. Turkin: Electron<br />
Cyclotron Current Drive Predictions for ITER: comparison of<br />
different models. (4 th IAEA Technical Meeting on ECRH Physics<br />
and Technology for ITER, <strong>2007</strong>-06-06 to <strong>2007</strong>-06-08, Vienna).
Marushchenko, N. B., H. Maaßberg and Yu. Turkin: Electron<br />
Cyclotron Current Drive Preditions for ITER: comparsion of<br />
the different models. (19 th Joint Russian-German Workshop<br />
on ECRH and Gyrotrons, <strong>2007</strong>-07-18 to <strong>2007</strong>-07-24, Garching).<br />
Masuzaki, S., M. Kobayashi, Y. Feng, T. Morisaki, T. Watanabe,<br />
N. Ohyabu and LHD Experimental Group: Study of edge<br />
plasma transport in LHD. (11 th International Workshop on<br />
Plasma Edge Theory in Fusion Devices (PET 11), <strong>2007</strong>-05-23<br />
to <strong>2007</strong>-05-25, Takayama-city).<br />
Matyash, K., R. Schneider, R. Sydora and F. Tacogna: Application<br />
of Complex Particle Kinetics to collisionless sheath.<br />
(11 th International Workshop on Plasma Edge Theory in<br />
Fusion Devices (PET 11), <strong>2007</strong>-05-23 to <strong>2007</strong>-05-25,<br />
Takayama-city).<br />
Mayer, M.: FT 3.25: Erosion/Deposition in the JET divertor.<br />
(Special TFE meeting on material erosion, migration and<br />
fuel retention in JET, <strong>2007</strong>-03-09 to <strong>2007</strong>-03-09, Culham).<br />
Mayer, M.: RESOLNRA: A new program for optimizing the<br />
achievable depth resolution in ion beam analysis methods.<br />
(18 th International Conference on Ion Beam Analysis,<br />
<strong>2007</strong>-09-23 to <strong>2007</strong>-09-28, Hyderabad, India).<br />
Mayer, M., V. Rohde, J. Chen, X. Gong, J. Likonen, S. Lindig,<br />
G. Ramos, E. Vainonen-Ahlgren and ASDEX Upgrade Team:<br />
Carbon Erosion and Transport in ASDEX Upgrade. (9 th ITPA<br />
Meeting on SOL/divertor physics, <strong>2007</strong>-05-07 to <strong>2007</strong>-05-10,<br />
Garching).<br />
Mayer, M., V. Rohde, J. Chen, X. Gong, J. Likonen, S. Lindig,<br />
G. Ramos, E. Vainonen-Ahlgren and ASDEX-Upgrade Team:<br />
Erosion of carbon and tungsten in the outer divertor of<br />
ASDEX-Upgrade. (2 nd German-Finnish Workshop on Material<br />
Migration in Fusion Devices: Measurements and Modelling,<br />
<strong>2007</strong>-02-26 to <strong>2007</strong>-02-27, Tervaniemi).<br />
Mayer, M., V. Rohde, J. Likonen, S. Lindig, G. Ramos, E. Vainonen-<br />
Ahlgren and ASDEX Upgrade Team: W marker erosion in<br />
ASDEX Upgrade. (Special Expert Working Group meeting<br />
on High-Z Plasma Facing Components, <strong>2007</strong>-05-10 to<br />
<strong>2007</strong>-05-11, Garching).<br />
Mayer, M., V. Rohde, G. Ramos, E. Vainonen-Ahlgren, J. Likonen,<br />
A. Herrmann and ASDEX Upgrade Team: Deuterium Inventory<br />
in ASDEX Upgrade. (9 th ITPA Meeting on SOL/divertor<br />
physics, <strong>2007</strong>-05-07 to <strong>2007</strong>-05-10, Garching).<br />
Meyer-Spasche, R.: Frauen in Mathematik und Physik. (Herbstuniversität<br />
<strong>für</strong> Schülerinnen, <strong>2007</strong>-10-29 to <strong>2007</strong>-10-30,<br />
Technische Universität München).<br />
Lectures<br />
163<br />
Meyer-Spasche, R.: Introduction to Functional Analysis.<br />
(WS 2006/<strong>2007</strong>. Vorlesung, Technische Universität München).<br />
Meyer-Spasche, R.: Mathematische Probleme in Fluiddynamik<br />
und <strong>Plasmaphysik</strong>. (SS <strong>2007</strong>. Vorlesung, Technische<br />
Universität München).<br />
Michel, G., H. Braune, V. Erckmann, H. Laqua, F. Noke, F. Purps,<br />
M. Dammertz, M. Thumm, C. Lechte and O. Dumbrais: Dual<br />
frequency operation of the W7-X gyrotron. (19 th Joint Russian-<br />
German Workshop on ECRH and Gyrotrons, <strong>2007</strong>-07-18 to<br />
<strong>2007</strong>-07-24, Karlsruhe/Stuttgart/Garching).<br />
Michel, G., F. Noke and P. Uhren: Integrated long-pulse control<br />
of gyrotrons. (19 th Joint Russian-German Workshop on<br />
ECRH and Gyrotrons, <strong>2007</strong>-07-18 to <strong>2007</strong>-07-24, Karlsruhe/<br />
Stuttgart/Garching).<br />
Mishchenko, A., A. Könies, P. Helander, Y. Turkin and<br />
R. Kleiber: Collisionless damping of zonal flow in 3D geometry.<br />
(Theory Meeting Sellin, <strong>2007</strong>-11-19 to <strong>2007</strong>-11-23,<br />
Sellin).<br />
Missal, B., A. Cardella, M. Schrader, T. Koppe and P. Friedrich:<br />
Mechanical Experiments about Pendulum Support of Vacuum<br />
Vessel W7-X. (8 th International Symposium on Fusion Nuclear<br />
Technology (ISFNT-8), <strong>2007</strong>-09-30 to <strong>2007</strong>-10-05, Heidelberg).<br />
Moro, A., W. A. Bongers, A. Bruschi, M. F. Graswinckel, E. Poli,<br />
D. M. S. Ronden and A. G. A. Verhoeven: Beam characteristics<br />
including general astigmatism effects in the Remote Steering<br />
ITER ECRH Upper Launcher. (4 th IAEA Technical Meeting<br />
on ECRH Physics and Technology for ITER, <strong>2007</strong>-06-06 to<br />
<strong>2007</strong>-06-08, Vienna).<br />
Mueck, A., A. Flaws, A. Gude and V. Igochine: Recent Development<br />
of the Soft X-Ray Diagnostic System in ASDEX<br />
Upgrade. (DPG AMOP-Frühjahrstagung, <strong>2007</strong>-03-19 to<br />
<strong>2007</strong>-03-23, Düsseldorf).<br />
Müller, H. W.: Basic Plasma Physics. (<strong>IPP</strong> Summer University<br />
for Plasma Physics, <strong>2007</strong>-09-24 to <strong>2007</strong>-09-28, Greifswald).<br />
Müller, W.-C. and M. Momeni: Monoscaling and Lévy laws<br />
in turbulence. (10 th MHD Days, <strong>2007</strong>-11-26 to <strong>2007</strong>-11-29,<br />
Garching).<br />
Neu, R.: Experimental results. (<strong>IPP</strong> Summer University on<br />
Plasma Physics, <strong>2007</strong>-09-24 to <strong>2007</strong>-09-28, Greifswald).<br />
Neu, R.: Fourth <strong>Report</strong> of the SEWG on Hig-Z PFCs. (6 th<br />
Meeting of Contact Persons of the EU-PWI Task Force,<br />
<strong>2007</strong>-10-29 to <strong>2007</strong>-10-31, Madrid).
Neu, R.: Initial operation of ASDEX Upgrade with 100 %<br />
tungsten PFCs. (9 th ITPA Meeting on Divertor and SOL<br />
Physics, <strong>2007</strong>-05-10 to <strong>2007</strong>-05-11, <strong>IPP</strong> Garching).<br />
Neu, R.: Kernfusion – eine Option <strong>für</strong> morgen? (Veranstaltung<br />
Studium Generale, <strong>2007</strong>-06-12, Universität Tübingen).<br />
Neu, R.: Kernfusion – eine zukünftige Energiequelle? (Veranstaltung<br />
der Akademie <strong>für</strong> Lehrerfortbildung und Personalführung,<br />
<strong>2007</strong>-09-05, Dillingen).<br />
Neu, R.: Operation with metallic wall: Feedback from AUG<br />
and FTU. (EFPW Meeting, <strong>2007</strong>-12-03 to <strong>2007</strong>-12-05, Prague).<br />
Neu, R.: Operation with tungsten plasma facing components<br />
in ASDEX Upgrade. (CEA Seminar, <strong>2007</strong>-09-21, Cadarache).<br />
Neu, R.: <strong>Plasmaphysik</strong> und Fusionsforschung I. (WS 2006/<br />
<strong>2007</strong>, SS <strong>2007</strong>. Vorlesung, Universität Tübingen).<br />
Neu, R.: <strong>Plasmaphysik</strong> und Fusionsforschung II. (SS <strong>2007</strong>.<br />
Vorlesung, Universität Tübingen).<br />
Neu, R.: Wolfram – eine Option <strong>für</strong> ITER? (Plasmakolloquium<br />
des IPF, <strong>2007</strong>-04-07, Universität Stuttgart).<br />
Neu, R. and ASDEX Upgrade Team: Plasma operation with<br />
high-Z environment. (17 th International Vacuum Congress<br />
(IVC-17), 13 th International Conference on Surface Science<br />
(ICSS-13), International Conference on Nano Science and<br />
Technology (ICN+T <strong>2007</strong>), 6 th Nordic Conference on<br />
Surface Science (NCSS-6), 22 nd Nordic Semiconductor<br />
Meeting (NSM-22), 4 th Swedish Meeting on Vacuum and<br />
Materials Science (SVM-4), <strong>2007</strong>-06-07 to <strong>2007</strong>-06-06,<br />
Stockholm).<br />
Neu, R. and ASDEX Upgrade Team: The Tungsten programme<br />
at ASDEX Upgrade. (ADAS Workshop, <strong>2007</strong>-10-10 to<br />
<strong>2007</strong>-10-13, Schloss Ringberg, Tegernsee).<br />
Neu, R., V. Bobkov, R. Dux, T. Eich, H. Greuner, O. Gruber,<br />
A. Herrmann, L. Horton, A. Kallenbach, M. Kaufmann, P. Lang,<br />
C. F. Maggi, H. W. Müller, R. Pugno, T. Pütterich, V. Rohde,<br />
W. Schustereder, A. C. C. Sips, J. Stober, W. Suttrop,<br />
M. Wischmeier, H. Zohm and ASDEX Upgrade Team:<br />
Plasma operation in a divertor tokamak with all tungsten<br />
plasma facing components. (49 th <strong>Annual</strong> Meeting of the<br />
Division of Plasma Physics, <strong>2007</strong>-11-12 to <strong>2007</strong>-11-16,<br />
Orlando, FL).<br />
Neu, R., R. Dux, A. Kallenbach and ASDEX Upgrade Team:<br />
Plasma operation with high-Z-environment. (Meeting, University<br />
of Stockholm, <strong>2007</strong>-07-08 to <strong>2007</strong>-07-09, Stockholm).<br />
Lectures<br />
164<br />
Neu, R., T. Pütterich, R. Dux and ASDEX Upgrade Team:<br />
Spectroscopic Diagnostic of Tungsten in Fusion Plasmas.<br />
(Physics at EBIT and Advanced Research Light Sources<br />
(PEARL07), <strong>2007</strong>-03-08 to <strong>2007</strong>-03-14, Shanghai).<br />
Noack, S., A. Versteegh, B. Jüttner and G. Fußmann:<br />
Analysis of Long-Living Plasmoids at Atmospheric Pressure.<br />
(PLASMA <strong>2007</strong> – International Conference on Research<br />
and Applications of Plasmas combined with the 4 th German-<br />
Polish Conference on Plasma Diagnostics for Fusion and<br />
Applications and the 6 th French-Polish Seminar on Thermal<br />
Plasma in Space and Laboratory, <strong>2007</strong>-10-16 to <strong>2007</strong>-10-19,<br />
Greifswald).<br />
Noack, S., A. Versteegh, B. Jüttner and G. Fußmann:<br />
Spektroskopische Untersuchung von langlebigen Plasmoiden.<br />
(DPG AMOP-Frühjahrstagung, <strong>2007</strong>-03-19 to <strong>2007</strong>-03-23,<br />
Düsseldorf).<br />
Nold, B., M. Ramisch, V. Rohde, ASDEX Upgrade Team and<br />
U. Stroth: Vergleich dimensional ähnlicher Turbulenz in TJ-K<br />
und ASDEX Upgrade. (DPG AMOP-Frühjahrstagung,<br />
<strong>2007</strong>-03-19 to <strong>2007</strong>-03-23, Düsseldorf).<br />
Noterdaeme, J.-M.: EnTicE: European network on Training<br />
ion cyclotron Engineers. (ICRF Meetings <strong>2007</strong> (TFH/JET-<br />
ITER/EnTicE/EFDA Coordination Task Meeting), <strong>2007</strong>-04-16<br />
to <strong>2007</strong>-04-20, Schloss Ringberg, Tegernsee).<br />
Noterdaeme, J.-M.: ICRF Research and Development Needs.<br />
(EFDA Meeting: Heating and Current Drive Research and<br />
Developments, <strong>2007</strong>-07-03, Warsaw).<br />
Noterdaeme, J.-M.: ITER – ICRF and EnTicE. (Kolloquium,<br />
<strong>Institut</strong>e of Plasma Physics, <strong>2007</strong>-09-20, Prague).<br />
Noterdaeme, J.-M.: Kernreactortheorie. (WS 2006/<strong>2007</strong>.<br />
Vorlesung, Universiteit Gent).<br />
Noterdaeme, J.-M.: Nuclear Reactor Theory and Experiments.<br />
(SS <strong>2007</strong>. Vorlesung – Interuniversity Program Master, Nuclear<br />
Engineering, SCK/CEN (Studiencentrum voor Kernenergie/<br />
Centre pour Energie Nucleaire), Mol).<br />
Noterdaeme, J.-M.: Wave heating for fusion plasmas. (Erasmus<br />
Mundus – Fusion EP, <strong>2007</strong>-07-19 to <strong>2007</strong>-07-23, Zollernblick).<br />
Omar, B., A. Wierling, S. Günter and G. Poeke: Spectral line<br />
shapes in dense plasmas. (DPG AMOP-Frühjahrstagung,<br />
<strong>2007</strong>-03-19 to <strong>2007</strong>-03-23, Düsseldorf).<br />
Otte, M.: Plasmatechnik: Fusionsplasmen. (WS 2006/<strong>2007</strong>.<br />
Vorlesungen, Fachhochschule Stralsund).
Otte, M., D. Andruczyk, A. Komarov, A. Kozachek, L. Krupnik,<br />
H. P. Laqua, O. Lischtschenko, S. Marsen, Y. Y. Podoba,<br />
M. Schubert, F. Wagner, G. B. Warr and A. Zhezhera: Experimental<br />
results from the WEGA stellarator. (34 th European<br />
Physical Society Conference on Plasma Physics, <strong>2007</strong>-07-02<br />
to <strong>2007</strong>-07-06, Warsaw).<br />
Otte, M., D. Andruczyk, H. P. Laqua, O. Lischtschenko, S. Marsen,<br />
Y. Podoba, J. Schacht, F. Wagner, G. Warr and A. Werner:<br />
The WEGA experiment: results and prospect. (PLASMA<br />
<strong>2007</strong> – International Conference on Research and Applications<br />
of Plasmas combined with the 4 th German-Polish Conference<br />
on Plasma Diagnostics for Fusion and Applications<br />
and the 6 th French-Polish Seminar on Thermal Plasma in<br />
Space and Laboratory, <strong>2007</strong>-10-16 to <strong>2007</strong>-10-19, Greifswald).<br />
Pfannmöller, J., O. Grulke, T. Klinger and K. Sauer: Experimentelle<br />
Untersuchungen nicht-linearer Phänomene von<br />
Whistlerwellen. (DPG AMOP-Frühjahrstagung, <strong>2007</strong>-03-19<br />
to <strong>2007</strong>-03-23, Düsseldorf).<br />
Podoba, Y., M. Otte, F. Wagner, M. Schubert, I. Bondarenko,<br />
A. Chmyga, G. Deshko, A. Komarov, A. Kozachok, L. Krupnik,<br />
S. Khrebtov, A. Zhezhera, A. Melnikov and S. Perfilov: First<br />
HIBP results on the WEGA Stellarator. (PLASMA <strong>2007</strong> –<br />
International Conference on Research and Applications of<br />
Plasmas combined with the 4 th German-Polish Conference<br />
on Plasma Diagnostics for Fusion and Applications and the<br />
6 th French-Polish Seminar on Thermal Plasma in Space and<br />
Laboratory, <strong>2007</strong>-10-16 to <strong>2007</strong>-10-19, Greifswald).<br />
Podoba, Y., M. Schubert and A. Zhezhera: First Results of<br />
Heavy Ion Beam Probing at WEGA. (DPG AMOP-Frühjahrstagung,<br />
<strong>2007</strong>-03-19 to <strong>2007</strong>-03-23, Düsseldorf).<br />
Pokol, G., G. Papp, G. Por, S. Zoletnik, A. Weller and W7-AS Team:<br />
Experimental Study and Simulation of W7-AS Transient MHD<br />
Mode. (PLASMA <strong>2007</strong> – International Conference on Research<br />
and Applications of Plasmas combined with the 4 th German-<br />
Polish Conference on Plasma Diagnostics for Fusion and Applications<br />
and the 6 th French-Polish Seminar on Thermal Plasma in<br />
Space and Laboratory, <strong>2007</strong>-10-16 to <strong>2007</strong>-10-19, Greifswald).<br />
Poli, E.: Introduction to kinetic plasma theory. (<strong>IPP</strong> Summer<br />
University for Plasma Physics, <strong>2007</strong>-09-24 to <strong>2007</strong>-09-28,<br />
Greifswald).<br />
Poli, E., W. A. Bongers, A. Bruschi, D. Farina, M. F. Graswinckel,<br />
M. A. Henderson, A. Moro, G. Ramponi, G. Saibene,<br />
A. G. A. Verhoeven and H. Zohm: Performance Evaluation of the<br />
Remote-Steering Option for the ITER EC Upper Launcher.<br />
(4 th IAEA Technical Meeting on ECRH Physics and Technology<br />
for ITER, <strong>2007</strong>-06-06 to <strong>2007</strong>-06-08, Vienna).<br />
Lectures<br />
165<br />
Poli, E., A. Peeters, A. Bergmann and A. Bottino: Dynamics<br />
of magnetic islands in tokamak. (DPG AMOP-Frühjahrstagung,<br />
<strong>2007</strong>-03-19 to <strong>2007</strong>-03-23, Düsseldorf).<br />
Preinhaelter, J., J. Urban, H. P. Laqua, L. Vahala and G. Vahala:<br />
Simulations of EBW heating in WEGA. (17 th Topical Conference<br />
on Radio Frequency Power in Plasmas, <strong>2007</strong>-05-07 to<br />
<strong>2007</strong>-05-09, Clearwater, FL).<br />
Preuss, R. and U. von Toussaint: Comparison of numerical<br />
methods for evidence calculation. (27 th International Workshop<br />
on Bayesian Inference and <strong>Max</strong>imum Entropy Methods<br />
in Science and Engineering (<strong>Max</strong>Ent <strong>2007</strong>), <strong>2007</strong>-07-08 to<br />
<strong>2007</strong>-07-13, Saratoga Springs, NY).<br />
Preuss, R. and U. von Toussaint: Numerical integration<br />
methods for model comparison. (27 th International Workshop<br />
on Bayesian Inference and <strong>Max</strong>imum Entropy Methods in<br />
Science and Engineering (<strong>Max</strong>Ent <strong>2007</strong>), <strong>2007</strong>-07-08 to<br />
<strong>2007</strong>-07-13, Saratoga Springs, NY).<br />
Rademann, D.: Leak Testing at Wendelstein 7-X during<br />
Assembly. (Symposium on Vacuum based Science and Technology,<br />
<strong>2007</strong>-09-05 to <strong>2007</strong>-09-07, Greifswald).<br />
Rahbarnia, K., E. Holzhauer, F. Greiner, A. Kendl, N. Mahdizadeh,<br />
M. Ramisch, B. Scott and U. Stroth: Elektromagnetische Turbulenz<br />
in TJ-K und ihre Abhängigkeit vom Plasma-β. (DPG<br />
AMOP-Frühjahrstagung, <strong>2007</strong>-03-19 to <strong>2007</strong>-03-23, Düsseldorf).<br />
Rampp, M.: MIGenAS: <strong>Max</strong>-<strong>Planck</strong> Integrated Gene Analysis<br />
System. (CASIMIR First Networking Meeting, <strong>2007</strong>-10-03<br />
to <strong>2007</strong>-10-06, Corfu).<br />
Rampp, M.: Computational aspects of large-scale analysis of<br />
metagenomics data. (Workshop SEQU07 – The Challenges in<br />
High-Throughput DNA-Sequencing, <strong>2007</strong>-04-30, Neuherberg).<br />
Rampp, M.: An Infrastructure for Computational Biology<br />
Applications. (Joint MPG-CNRS Workshop on “Systems<br />
Biology”, <strong>2007</strong>-09-24 to <strong>2007</strong>-09-26, Berlin).<br />
Ramponi, G., D. Farina, M.A. Henderson, E. Poli, O. Sauter,<br />
G. Saibene, H. Zohm, C. Zucca and H. Takahashi: Physics<br />
analysis of the ITER ECW system for an optimized performance.<br />
(4 th IAEA Technical Meeting on ECRH Physics and<br />
Technology for ITER, <strong>2007</strong>-06-06 to <strong>2007</strong>-06-08, Vienna).<br />
Reich, J., A. Cardella, U. Nielsen, R. Krause, R. Kairys, H. Jenzsch,<br />
M. Bednarek, G. Sobisch and B. Voslamber: Manufacture of<br />
Inter-Coil-Support-Elements of the W7-X Magnet System.<br />
(22 nd Symposium on Fusion Engineering, <strong>2007</strong>-06-17 to<br />
<strong>2007</strong>-06-21, Albuquerque, NM).
Reinelt, M. and C. Linsmeier: Deuterium Retention in Ocovered<br />
and Pure Beryllium. (EFDA SEWG Meeting on<br />
Mixed Materials, <strong>2007</strong>-07-09 to <strong>2007</strong>-07-10, JET, Culham).<br />
Reiter, D., H. Frerichs, D. Harting, Y. Feng and O. Schmitz:<br />
3D edge transport studies with EMC3-EIRENE for the Dynamic<br />
Ergodic Divertor (DED) at TEXTOR. (11 th International<br />
Workshop on Plasma Edge Theory in Fusion Devices<br />
(PET 11), <strong>2007</strong>-05-23 to <strong>2007</strong>-05-25, Takayama-city).<br />
Ribeiro, T.: Edge turbulence simulations: self consistent MHD<br />
equilibrium and the X-point singularity. (12 th European<br />
Fusion Theory Conference, <strong>2007</strong>-09-23 to <strong>2007</strong>-09-27,<br />
Madrid).<br />
Rohde, V.: Dust production by arc erosion. (Workshop on Dust<br />
in ITER – Technology Issues (Dust in Tokamak), Satellite<br />
Meeting of the 13 th International Conference on Fusion Reactor<br />
Materials (ICFRM-13), <strong>2007</strong>-12-14 to <strong>2007</strong>-12-15, Nice).<br />
Rohde, V.: Comparison of the 13 puff and long-term measurements.<br />
(2 nd German-Finnish Workshop on Material Migration<br />
in Fusion Devices, <strong>2007</strong>-02-26 to <strong>2007</strong>-02-27, Tervaniemi).<br />
Rohde, V., M. Balden, P. Sharpe, G. Antar and ASDEX Upgrade<br />
Team: Dust investigations at ASDEX Upgrade. (1 st Workshop<br />
on the “Dust in Fusion Plasmas”. Satellite Meeting of<br />
the 34 th EPS Conference on Plasma Physics, <strong>2007</strong>-07-08 to<br />
<strong>2007</strong>-07-10, Warsaw).<br />
Roth, J.: Choice of wall materials and compatibility of plasma<br />
operation. (2 nd EFDA Workshop, <strong>2007</strong>-10-08 to <strong>2007</strong>-10-09,<br />
Cadarache).<br />
Roth, J.: ITER Design Review and the EU PWI TF. (PMK<br />
Strategieklausur, <strong>2007</strong>-06-18, Garching).<br />
Roth, J.: Migration pattern of D into CFC. (ITPA SOL/Divertor<br />
Meeting, <strong>2007</strong>-05-07 to <strong>2007</strong>-05-10, Garching).<br />
Roth, J.: PWI and Edge Physics. (1 st EFDA Workshop,<br />
<strong>2007</strong>-07-17 to <strong>2007</strong>-07-19, Garching).<br />
Roth, J. and E. Tsitrone: The EU-PWI Task Force: recent<br />
achievements and midterm program. (EU PWI TF, STAC<br />
Meeting, <strong>2007</strong>-02-08 to <strong>2007</strong>-02-09, Brussels).<br />
Roth, J., E. Tsitrone and A. Loarte: The EU Plasma Wall<br />
Interaction Task Force: recent achievements and midterm<br />
program. (Association Day ÖAW, <strong>2007</strong>-06-19, Innsbruck).<br />
Roth, J., E. Tsitrone and A. Loarte: The EU Plasma Wall<br />
Interaction Task Force: recent achievements and midterm<br />
Lectures<br />
166<br />
program. (Meeting of the Association Euratom-<strong>IPP</strong>LM<br />
Council, <strong>2007</strong>-03-20, Warsaw).<br />
Roth, J., E. Tsitrone and A. Loarte: The EU-PWI Task<br />
Force: Work-Programme 2008. (EU PWI TF STAC Meeting,<br />
<strong>2007</strong>-05-24, Brussels).<br />
Roth, J., E. Tsitrone and A. Loarte: Plasma-Wall Interaction:<br />
A complex combination of surface processes critical for<br />
thermo-nuclear fusion. (Berliner Seminar über <strong>Plasmaphysik</strong>,<br />
<strong>2007</strong>-03-14, Humboldt-Universität Berlin).<br />
Roth, J., E. Tsitrone and A. Loarte: Plasma-Wall Interaction:<br />
A complex combination of surface processes critical for<br />
thermo-nuclear fusion. (17 th International Vacuum Congress,<br />
<strong>2007</strong>-07-02 to <strong>2007</strong>-07-06, Stockholm).<br />
Roth, J., E. Tsitrone, A. Loarte, G. F. Counsell and R. P. Doerner:<br />
Tritium inventory in ITER plasma-facing materials and<br />
tritium removal procedures. (13 th International Conference<br />
on Fusion Reactor Materials (ICFRM-13), <strong>2007</strong>-12-10 to<br />
<strong>2007</strong>-12-14, Nice).<br />
Rozhansky, V., E. Kaveeva, S. Voskoboynikova and D. Coster:<br />
Modelling of the radial electric field in the ASDEX Upgrade<br />
Ohmic shots. (11 th International Workshop on Plasma Edge<br />
Theory in Fusion Devices (PET 11), <strong>2007</strong>-05-23 to <strong>2007</strong>-05-25,<br />
Takayama-city).<br />
Ruset, C., E. Grigore, H. Maier and R. Neu: Combined<br />
Magnetron Sputtering and Ion Implantation – a High Energy<br />
Ion Assisted Deposition Method for Producing Nanostructurated<br />
Coatings. (Materials Science & Technology <strong>2007</strong><br />
Conference, <strong>2007</strong>-09-16 to <strong>2007</strong>-09-20, Detroit, MI).<br />
Ryter, F., J. C. Fuchs, W. Schneider, A. C. C. Sips, A. Stäbler,<br />
J. Stober and ASDEX Upgrade Team: H-mode confinement<br />
properties close to the power threshold in ASDEX Upgrade.<br />
(11 th IAEA TM on H-mode Physics and Transport Barriers,<br />
<strong>2007</strong>-09-26 to <strong>2007</strong>-09-28, Tsukuba).<br />
Ryter, F., J. C. Fuchs, W. Schneider, A. C. C. Sips, J. Stober<br />
and ASDEX Upgrade Team: Status of the ASDEX Upgrade<br />
data in the ITPA confinement data base. (12 th ITPA Confinement<br />
Database and Modelling Workshop, <strong>2007</strong>-05-07 to<br />
<strong>2007</strong>-05-10, Lausanne).<br />
Rzesnicki, T., B. Piosczyk, J. Flamm, G. Gantenbein, J. Jin,<br />
M. Thumm and G. Michel: The quasi-optical RF output system<br />
for the 170 GHz, 2 MW coaxial cavity gyrotron. (19 th Joint<br />
Russian-German Workshop on ECRH and Gyrotrons,<br />
<strong>2007</strong>-07-18 to <strong>2007</strong>-07-24, Karlsruhe/Stuttgart/Garching).
Sangines, R., D. Andruczyk, R. N. Tarrant, M. M. Bilek and<br />
D. R. Mc Kenzie: Characterization of a filtered pulsed catholic<br />
vacuum wave plasma source: plasma transport analysis.<br />
(PLASMA <strong>2007</strong> – International Conference on Research and<br />
Applications of Plasmas combined with the 4 th German-Polish<br />
Conference on Plasma Diagnostics for Fusion and Applications<br />
and the 6 th French-Polish Seminar on Thermal Plasma in<br />
Space and Laboratory, <strong>2007</strong>-10-16 to <strong>2007</strong>-10-19, Greifswald).<br />
Sardei, F., A. Brooks, Y. Feng, F. Herrnegger, T. Kaiser,<br />
J. Kißlinger, R. Maingi, D. Monticello and M.C. Zarnstorff:<br />
EMC3-EIRENE implementation on NCSX and first applications.<br />
(Joint Conference of 17 th International Toki Conference<br />
on Physics of Flows and Turbulence in Plasmas and<br />
16 th International Stellarator/Heliotron Workshop, <strong>2007</strong>-10-15<br />
to <strong>2007</strong>-10-19, Ceratopia Toki, Gifu).<br />
Sárközi, J., K. Grosser, G. Kocsis, R. König, U. Neuner,<br />
A. Molnár, G. Petravich, G. Por, G. Porempovics, S. Recsei,<br />
V. Szabó, A. Szappanos and S. Zoletnik: Video Diagnostic<br />
for W7-X Stellarator. (International Conference Plasma<br />
<strong>2007</strong> on Research and Application of Plasmas, <strong>2007</strong>-10-16<br />
to <strong>2007</strong>-10-19, Greifswald).<br />
Schacht, J., H. Laqua, A. Spring, I. Müller, S. Pingel and<br />
A. Wölk: Stellarator WEGA as a test-bed for the Wendelstein 7-X<br />
control system concepts. (6 th IAEA Technical Meeting on<br />
Control, Data Acquisition, and Remote Participation for<br />
Fusion Research, <strong>2007</strong>-06-04 to <strong>2007</strong>-06-08, Inuyama).<br />
Schacht, J., H. Laqua, A. Spring, I. Müller, S. Pingel, A. Wölk<br />
and G. Kühner: Standardized communication in the control<br />
system of the experiment Wendelstein 7-X. (15 th IEEE Real<br />
Time Conference, <strong>2007</strong>-04-28 to <strong>2007</strong>-05-04, Batavia).<br />
Schacht, J., S. Pingel and A. Wölk: Die Konzeption der Sicherheitssteuerung<br />
<strong>für</strong> das Fusionsexperiment Wendelstein 7-X.<br />
(12. Symposium Maritime Elektrotechnik, Elektronik und<br />
Informationstechnologie, <strong>2007</strong>-10-08 to <strong>2007</strong>-10-10, Rostock).<br />
Schmitz, O., M. W. Jakubowski, T. E. Evans, M. J. Schaffer,<br />
W. P. West, M. E. Fenstermacher, M. Groth, C. Lasnier,<br />
I. Joseph, R. Moyer, B. Unterberg and H. Frerichs: Divertor<br />
heat and particle fluxes during ELM control experiments.<br />
(49 th <strong>Annual</strong> APS Division of Plasma Physics Meeting,<br />
<strong>2007</strong>-11-12 to <strong>2007</strong>-11-16, Orlando, FL).<br />
Schmuck, S., A. Dinklage, R. Fischer, J. P. Knauer, B. Kurzan,<br />
H.-D. Murmann and E. Pasch: Design and calibration of<br />
Thomson scattering polychromator for Wendelstein 7-X.<br />
(PLASMA <strong>2007</strong> – International Conference on Research and<br />
Applications of Plasmas combined with the 4 th German-Polish<br />
Conference on Plasma Diagnostics for Fusion and Applica-<br />
Lectures<br />
167<br />
tions and the 6 th French-Polish Seminar on Thermal Plasma in<br />
Space and Laboratory, <strong>2007</strong>-10-16 to <strong>2007</strong>-10-19, Greifswald).<br />
Schmuck, S., A. Dinklage, R. Fischer, J. P. Knauer, B. Kurzan,<br />
H.-D. Murmann and E. Pasch: Optimierung eines Detektionssystems<br />
<strong>für</strong> die Thomson-Streuung. (DPG AMOP-Frühjahrstagung,<br />
<strong>2007</strong>-03-19 to <strong>2007</strong>-03-23, Düsseldorf).<br />
Schustereder, W., N. Endstrasser, B. Rasul, F. Zappa, V. Grill,<br />
P. Scheier and T. Märk: Quantification of the sticking coefficient<br />
of hydrocarbons on fusion relevant carbon and tungsten<br />
surfaces. (28 th International Conference on Phenomena<br />
in Ionized Gases (ICPIG), <strong>2007</strong>-07-15 to <strong>2007</strong>-07-20, Prague).<br />
Schwarz, B., P. Worbs and C. Eisenmenger-Sittner: Applications<br />
of a High Temperature Sessile Drop Device. (17 th International<br />
Vacuum Congress (IVC-17), 13 th International<br />
Conference on Surface Science (ICSS-13), International Conference<br />
on Nano Science and Technology (ICN+T <strong>2007</strong>),<br />
6 th Nordic Conference on Surface Science (NCSS-6),<br />
22 nd Nordic Semiconductor Meeting (NSM-22), 4 th Swedish<br />
Meeting on Vacuum and Materials Science (SVM-4), <strong>2007</strong>-07-02<br />
to <strong>2007</strong>-07-06, Stockholm).<br />
Schwarz-Selinger, T.: Quantitative Mass Spectrometry of<br />
Reactive Plasmas – Sensitivity Studies with Bayesian Data<br />
Analysis. (Symposium on Vacuum Based Science and Technology,<br />
<strong>2007</strong>-09-05 to <strong>2007</strong>-09-07, Greifswald).<br />
Schwarz-Selinger, T. and W. Jacob: Stickstoffbeimischung<br />
in die Plasmarandschicht – eine Lösung <strong>für</strong> die Redepositionsproblematik<br />
in Fusionsexperimenten. (Arbeitsgruppenseminar,<br />
Lehrstuhl <strong>für</strong> experimentelle <strong>Plasmaphysik</strong>,<br />
<strong>2007</strong>-10-09, Humboldt-Universität Berlin).<br />
Schwarz-Selinger, T., W. Jacob and C. Hopf: Stickstoffbeimischung<br />
in Kohlenwasserstoffplasmen – eine Lösung <strong>für</strong> die<br />
Redepositionsproblematik in Fusionsexperimenten? (14. Erfahrungsaustausch<br />
Oberflächentechnologie mit Plasma- und<br />
Ionenstrahlprozessen, <strong>2007</strong>-03-13 to <strong>2007</strong>-03-15, Mühlleithen).<br />
Schweinzer, J.: Atomic collision processes in plasmas of<br />
ASDEX Upgrade, JET and ITER. (Atomphysik Seminar,<br />
<strong>2007</strong>-11-14, Darmstadt).<br />
Schweinzer, J.: Atomic collision processes in plasmas of<br />
ASDEX Upgrade, JET and ITER. (20 th International Symposium<br />
on Ion-Atom Collisions, <strong>2007</strong>-08-02 to <strong>2007</strong>-08-04,<br />
Agios Nikolaos).<br />
Schweinzer, J.: The lithium beam modelling database and its<br />
extension to sodium. (ADAS Workshop, <strong>2007</strong>-10-12, Schloss<br />
Ringberg, Tegernsee).
Schweinzer, J.: Status of ASDEX Upgrade. (IEA Large<br />
Tokamak & Poloidal Divertor Workshop on Implementation<br />
of ITPA Coordinated Research Recommendations, <strong>2007</strong>-11-29,<br />
Culham).<br />
Schweinzer, J. and E. Wolfrum: Grundlagen des Kernfusionsreaktors.<br />
(SS <strong>2007</strong>. Vorlesung, Technische Universität Wien).<br />
Scott, B.: Self Consistent Nonlinear Burst Phenomena in<br />
Tokamak Edge Turbulence. (DPG AMOP-Frühjahrstagung,<br />
<strong>2007</strong>-03-19 to <strong>2007</strong>-03-23, Düsseldorf).<br />
Seidel, R., C. Biedermann, R. Radtke and T. Pütterich: Experimentelle<br />
und theoretische Bestimmung der Wellenlängen<br />
von Emissionslinien im Röntgenbereich hochgeladener<br />
Wolframionen. (DPG AMOP-Frühjahrstagung, <strong>2007</strong>-03-19<br />
to <strong>2007</strong>-03-23, Düsseldorf).<br />
Shimizu, S., T. Shimizu, W. Jacob, H. Thomas, N. Sato and<br />
G. E. Morfill: Microcrystalline Diamond Growth on Seed<br />
Particles and Thermophoretic Effect on Levitated Fine<br />
Diamond Particles in an RF Plasma Sheath. (18 th European<br />
Conference on Diamond, Diamond-Like Materials, Carbon<br />
Nanotubes, and Nitrides, <strong>2007</strong>-09-09 to <strong>2007</strong>-09-14, Berlin).<br />
Shimozuma, T., S. Kubo, H. Igami, Y. Yoshimura, T. Notake,<br />
N. B. Marushchenko, Yu. Turkin, T. Mutoh and LHD Experimental<br />
Group: Efficient heating at the 3 rd harmonic Electron<br />
cyclotron resonance in Large Helical Device. (Joint Conference<br />
of the 17 th International Toki Conference on Physics of<br />
Flows and Turbulence in Plasmas and 16 th International<br />
Stellarator/Heliotron Workshop, <strong>2007</strong>-10-15 to <strong>2007</strong>-10-19,<br />
Ceratopia Toki, Gifu).<br />
Simon-Weidner, J.: The Shrunk Finite Element (SFE) Method:<br />
Simulation of Crack Propagation in 3-D. (NAFEMS World<br />
Congress, <strong>2007</strong>-05-22 to <strong>2007</strong>-05-25, Vancouver).<br />
Stäbler, A. and AUG-Team: The Role of the Different<br />
Heating Systems in Optimising ASDEX Upgrade Discharges.<br />
(EFDA Meeting: Heating and Current Drive Research and<br />
Developments, <strong>2007</strong>-07-03, Warsaw).<br />
Stark, A., W. Fox, J. Egedal, O. Grulke and T. Klinger: Observation<br />
of localized ion heating during driven collisionless<br />
magnetic reconnection. (The 9 th International Workshop on<br />
the Interrelationship between Plasma Experiments in Laboratory<br />
and Space (IPELS), <strong>2007</strong>-08-05 to <strong>2007</strong>-08-10, Cairns).<br />
Stark, A., O. Grulke and T. Klinger: Experimentelle Untersuchungen<br />
zu nichtlinear angeregten alfvénischen Wellen in<br />
VINETA. (DPG AMOP-Frühjahrstagung, <strong>2007</strong>-03-19 to<br />
<strong>2007</strong>-03-23, Düsseldorf).<br />
Lectures<br />
168<br />
Stark, A., O. Grulke and T. Klinger: Nonlinear excitation of<br />
Alfvénic waves by helicon modulation. (The 9 th International<br />
Workshop on the Interrelationship between Plasma<br />
Experiments in Laboratory and Space (IPELS), <strong>2007</strong>-08-05<br />
to <strong>2007</strong>-08-10, Cairns).<br />
Starke, P., C. Adelhelm, M. Balden and U. Fantz: Chemical<br />
Erosion of Doped Carbon Layers in Deuterium Low Pressure<br />
FR Plasmas. (European Congress and Exhibition on Advanced<br />
Materials and Processes (EUROMAT <strong>2007</strong>), <strong>2007</strong>-09-10 to<br />
<strong>2007</strong>-09-13, Nürnberg).<br />
Starke, P., C. Adelhelm, M. Balden, U. Fantz, A. Centeno and<br />
C. Blanco: Erosionsausbeuten dotierter Kohlenstoffmaterialien<br />
in Deuterium-Niedertemperaturplasmen. (DPG AMOP-<br />
Frühjahrstagung, <strong>2007</strong>-03-19 to <strong>2007</strong>-03-23, Düsseldorf).<br />
Starke, P., S. Christ-Koch, S. K. Karkari, C. Gaman, U. Fantz<br />
and A. R. Ellingboe: Performance of a Langmuir probe and<br />
a hairpin resonance probe in inductively coupled low pressure<br />
plasmas. (28 th International Conference on Phenomena in<br />
Ionized Gases (ICPIG), <strong>2007</strong>-07-15 to <strong>2007</strong>-07-20, Prague).<br />
Stober, J., A. Manini, M. Maraschek, F. Meo, R. Neu, D. Wagner,<br />
H. Zohm and ASDEX Upgrade Team: ASDEX Upgrade<br />
results with the upgraded ECRH system. (19 th Joint Russian-<br />
German Meeting on ECRH and Gyrotrons, <strong>2007</strong>-07-23,<br />
Garching).<br />
Stober, J., A. C. C. Sips, C. Angioni, C. B. Forest, O. Gruber,<br />
J. Hobirk, L. D. Horton, C. F. Maggi, M. Maraschek, P. Martin,<br />
P. J. McCarthy, V. Mertens, Y.-S. Na, M. Reich, A. Stäbler,<br />
G. Tardini, H. Zohm and ASDEX Upgrade Team: The role of<br />
the current profile in the improved H-mode scenario in<br />
ASDEX Upgrade. (49 th <strong>Annual</strong> Meeting of the Division of<br />
Plasma Physics, <strong>2007</strong>-11-12 to <strong>2007</strong>-11-16, Orlando, FL).<br />
Strumberger, E., S. Günter, E. Schwarz, C. Tichmann and<br />
ASDEX Upgrade Team: Fast Particle Losses Due to NTMS<br />
and Magnetic Field Ripple. (49 th <strong>Annual</strong> Meeting of the<br />
Division of Plasma Physics, <strong>2007</strong>-11-12 to <strong>2007</strong>-11-16,<br />
Orlando, FL).<br />
Strumberger, E., P. Merkel, M. Sempf and S. Günter: Fully<br />
3D RWM and Feedback Stabilization Studies for ITER and<br />
AUG. (49 th <strong>Annual</strong> Meeting of the Division of Plasma Physics,<br />
<strong>2007</strong>-11-12 to <strong>2007</strong>-11-16, Orlando, FL).<br />
Subba, F., X. Bonnin, D. Coster, A. Kukushkin, A. Loarte,<br />
D. Reiter and R. Zanino: 2D Fluid Modeling of far SOL<br />
Divertor Plasma Including the First Wall. (11 th International<br />
Workshop on Plasma Edge Theory in Fusion Devices (PET 11),<br />
<strong>2007</strong>-05-23 to <strong>2007</strong>-05-25, Takayama-city).
Suttrop, W.: Tokamak equilibrium, transport and stability.<br />
(<strong>IPP</strong> Summer University on Plasma Physics, <strong>2007</strong>-09-24 to<br />
<strong>2007</strong>-09-28, Greifswald).<br />
Suttrop, W., T. Bertoncelli, P. Brunsell, T. Eich, E. Gaio, O. Gruber,<br />
F. Gnesotto, S. Günter, P. Merkel, M. Rott, T. Vierle, S. Schweizer,<br />
U. Seidel, M. Sempf, B. Streibl, E. Strumberger, V. Toigo, H. Zohm<br />
and ASDEX Upgrade Team: Design of in-vessel saddle coils<br />
at ASDEX. (Biennial Workshop “Stochasticity in Fusion<br />
Plasmas” (SFP <strong>2007</strong>), <strong>2007</strong>-03-05 to <strong>2007</strong>-03-07, Jülich).<br />
Suzuki, A., T. Chikada, B. A. Pint, D. Levchuk, T. Muroga and<br />
T. Terai: Fabrication and properties of Fe-erbia double layer<br />
coatings on V alloy for Li/V blanket application. (22 nd Symposium<br />
on Fusion Engineering (SOFE 07), <strong>2007</strong>-06-18 to<br />
<strong>2007</strong>-06-22, Albuquerque, NM).<br />
Suzuki, A., B. Pint, M. Li, D. Levchuk, F. Koch, T. Muroga and<br />
T. Terai: Compatibility of MHD coating candidate materials<br />
with liquid lithium under neutron irradiation. (13 th International<br />
Conference on Fusion Reactor Materials (ICFRM-13),<br />
<strong>2007</strong>-12-10 to <strong>2007</strong>-12-14, Nice).<br />
Suzuki, Y., H. Kawashima, D. P. Coster, S. Sakurai, K. Shimizu<br />
and T. Takizuka: Simulation Study of Radiative Cooling in<br />
the Divertor on JT-60 Super Advanced (JT-60SA). (11 th International<br />
Workshop on Plasma Edge Theory in Fusion Devices<br />
(PET 11), <strong>2007</strong>-05-23 to <strong>2007</strong>-05-25, Takayama-city).<br />
Sydorenko, N., A. Grulke, A. Stark and T. Klinger: Measurements<br />
of the negative ion concentration in argon-oxygen<br />
discharges using photodetachment. (DPG AMOP-Frühjahrstagung,<br />
<strong>2007</strong>-03-19 to <strong>2007</strong>-03-23, Düsseldorf).<br />
Szepesi, T., S. Kalvin, G. Kocsis, P. T. Lang and ASDEX Upgrade<br />
Team: Investigations of the ELM triggering mechanism:<br />
HFS and LFS pellet injections. (10 th Workshop on the Electric<br />
Fields, Structures, and Relaxation in Plasmas, <strong>2007</strong>-07-08 to<br />
<strong>2007</strong>-07-09, Warsaw).<br />
Taccogna, F., R. Schneider, S. Longo and M. Capitelli: Plasma-<br />
Neutral Interaction in Kinetic Models for the Divertor Region.<br />
(11 th International Workshop on Plasma Edge Theory in Fusion<br />
Devices (PET 11), <strong>2007</strong>-05-23 to <strong>2007</strong>-05-25, Takayama-city).<br />
Thomsen, H., P. Carvalho, U. v. Toussaint, S. Gori, S. Mohr and<br />
A. Weller: The Steady-State Challenge for the X-Ray Tomography<br />
System on Wendelstein 7-X stellarator. (PLASMA <strong>2007</strong> –<br />
International Conference on Research and Applications of<br />
Plasmas combined with the 4 th German-Polish Conference<br />
on Plasma Diagnostics for Fusion and Applications and the<br />
6 th French-Polish Seminar on Thermal Plasma in Space and<br />
Laboratory, <strong>2007</strong>-10-16 to <strong>2007</strong>-10-19, Greifswald).<br />
Lectures<br />
169<br />
Thumm, M., G. Dammertz, G. Gantenbein, S. Illy, W. Leonhardt,<br />
G. Neffe, B. Piosczyk, M. Schmid, H. Braune, V. Erckmann,<br />
H. P. Laqua, G. Michel, M. Weißgerber, P. Brand, W. Kasparek<br />
and C. Lechte: 10 MW, 140 GHz, CW gyrotron and optical transmission<br />
system for millimeter wave heating of plasmas in<br />
the stellarator W7-X. (1 st Shenzhen International Conference<br />
on Advanced Science and Technology – THz Radiation<br />
Science and Technology, <strong>2007</strong>-11-18 to <strong>2007</strong>-11-23, Shenzhen).<br />
Thumm, M., G. Dammertz, G. Gantenbein, S. Illy, W. Leonhardt,<br />
G. Neffe, B. Piosczyk, M. Schmid, H. Braune, V. Erckmann,<br />
H. P. Laqua, G. Michel, M. Weißgerber, P. Brand, W. Kasparek<br />
and C. Lechte: 10 MW, 140 GHz, CW millimeter wave heating<br />
system for nuclear fusion plasma heating. (41 st IMPI <strong>Annual</strong><br />
Microwave Symposium, <strong>2007</strong>-08-01 to <strong>2007</strong>-08-03, Vancouver).<br />
Thumm, M., G. Dammertz, G. Gantenbein, S. Illy, W. Leonhardt,<br />
G. Neffe, B. Piosczyk, M. Schmid, H. Braune, V. Erckmann,<br />
H. Laqua, G. Michel, M. Weißgerber, P. Brand, W. Kasparek<br />
and C. Lechte: Progress on the 10 MW, 140 GHz ECH<br />
System for the stellarator W7-X. (IEEE <strong>2007</strong> Pulsed Power<br />
and Plasma Physics Conference, <strong>2007</strong>-06-17 to <strong>2007</strong>-06-22,<br />
Albuquerque, NM).<br />
Tomarchio, V. and K. Riße: The Manufacturing of the W7-X<br />
Superconducting Magnet System. (International Youth Conference<br />
on Energetics, <strong>2007</strong>-05-31 to <strong>2007</strong>-06-02, Budapest).<br />
Tsitrone, E., A. Loarte and J. Roth: Modelling activities of<br />
EU-PWI Task Force. (<strong>Annual</strong> Meeting of the Task Force<br />
ITM, <strong>2007</strong>-09-19 to <strong>2007</strong>-09-21, Garching).<br />
Tskhakaya, D., S. Kuhn, Y. Tomita, K. Matyash, R. Schneider<br />
and F. Taccogna: Self-consistent simulations of the plasmawall<br />
transition layer. (11 th International Workshop on Plasma<br />
Edge Theory in Fusion Devices (PET 11), <strong>2007</strong>-05-23 to<br />
<strong>2007</strong>-05-25, Takayama-city).<br />
Tskhakaya, D., F. Subba, X. Bonnin, D. Coster, W. Fundamenski,<br />
R. A. Pitts and JET EFDA Contributors: On kinetic effects<br />
during the parallel transport in the SOL. (11 th International<br />
Workshop on Plasma Edge Theory in Fusion Devices (PET 11),<br />
<strong>2007</strong>-05-23 to <strong>2007</strong>-05-25, Takayama-city).<br />
Turkin, Y., C. D. Beidler, V. Erckmann, H. P. Laqua, H. Maaßberg,<br />
N. B. Marushchenko and W7-X Team: ECRH and transport<br />
simulation for W7-X. (34 th European Physical Society Conference<br />
on Plasma Physics, <strong>2007</strong>-07-02 to <strong>2007</strong>-07-06, Warsaw).<br />
Turkin, Y., C. D. Beidler, V. Erckmann, H. P. Laqua, H. Maaßberg,<br />
N. B. Marushchenko and W7-X Team: ECRH and transport<br />
simulation for W7-X. (19 th Joint Russian-German Workshop<br />
on ECRH and Gyrotrons, <strong>2007</strong>-07-18 to <strong>2007</strong>-07-24, Garching).
Turkin, Y., C. D. Beidler, V. Erckmann, H. P. Laqua, H. Maaßberg,<br />
N. B. Marushchenko and W7-X Team: Electron cyclotron<br />
heating of plasma with density above 10 20 m -3 in W7-X. (Joint<br />
Conference of the 17 th International Toki Conference on<br />
Physics of Flows and Turbulence in Plasmas and 16 th International<br />
Stellarator/Heliotron Workshop, <strong>2007</strong>-10-15 to<br />
<strong>2007</strong>-10-19, Ceratopia Toki, Gifu).<br />
Turkin, Y., C. D. Beidler and H. Maaßberg: Predictive transport<br />
code: status and plans. (3 rd Coordinated Working Group<br />
Meeting (CWGM), <strong>2007</strong>-10-23 to <strong>2007</strong>-10-24, Toki).<br />
Ullrich, S., O. Grulke and T. Klinger: Experimentelle Untersuchungen<br />
zur Wechselwirkung von Drift- und Alfvénwellen.<br />
(DPG AMOP-Frühjahrstagung, <strong>2007</strong>-03-19 to <strong>2007</strong>-03-23,<br />
Düsseldorf).<br />
Ulrich, V., S. Barth, S. Joshi, T. Lischke and U. Hergenhahn:<br />
Energieaufgelöste koinzidente Messung von Photo- und<br />
Augerelektron nach Innerschalenionisation bei CO, CF 4 und O 2 .<br />
(DPG AMOP-Frühjahrstagung, <strong>2007</strong>-03-19 to <strong>2007</strong>-03-23,<br />
Düsseldorf).<br />
Vermare, L., C. Angioni, A. Bottino, A. G. Peeters and ASDEX<br />
Upgrade Team: β dependence of micro-instabilities using linear<br />
gyrokinetic simulations. (11 th IAEA TM on H-mode Physics<br />
and Transport Barriers, <strong>2007</strong>-09-26 to <strong>2007</strong>-09-28, Tsukuba).<br />
Vermare, L., C. C. Petty, G. R. McKee, F. Ryter, J. R. Ferron,<br />
R. J. Gröbner, A. W. Hyatt, A. W. Leonard, T. C. Luce, ASDEX<br />
Upgrade Team and DIII-D Team: Comparison of the β dependence<br />
of micro-instabilities using linear gyrokinetic simulations.<br />
(11 th IAEA TM on H-mode Physics and Transport<br />
Barriers, <strong>2007</strong>-09-26 to <strong>2007</strong>-09-28, Tsukuba).<br />
Versteegh, A., S. Noack, B. Jüttner and G. Fußmann: Analysis<br />
of long living plasmoid at atmospheric pressure. (DPG AMOP-<br />
Frühjahrstagung, <strong>2007</strong>-03-19 to <strong>2007</strong>-03-23, Düsseldorf).<br />
Von Toussaint, U.: Integrated Data Analysis. (<strong>Institut</strong>skolloquium,<br />
<strong>Institut</strong>e for Plasma Research, <strong>2007</strong>-02-06, Bhat, Gandhinagar).<br />
Von Toussaint, U.: Introduction to Bayesian Probability<br />
Theory: A Tutorial. (Theory-Group <strong>Institut</strong>e for Plasma<br />
Research, <strong>2007</strong>-02-22, Bhat, Gandhinagar).<br />
Von Toussaint, U.: <strong>IPP</strong>: Experiments and Research. (<strong>Institut</strong>skolloquium,<br />
<strong>Institut</strong>e for Plasma Research, <strong>2007</strong>-02-20,<br />
Bhat, Gandhinagar).<br />
Von Toussaint, U.: Towards sustainable fusion power.<br />
(California <strong>Institut</strong>e of Technology, <strong>2007</strong>-06-28 to <strong>2007</strong>-06-28,<br />
Pasadena, CA).<br />
Lectures<br />
170<br />
Von Toussaint, U. and S. Gori: Deconvolution using Thin-<br />
Plate Splines. (27 th International Workshop on Bayesian<br />
Inference and <strong>Max</strong>imum Entropy Methods in Science and<br />
Engineering (<strong>Max</strong>Ent <strong>2007</strong>), <strong>2007</strong>-07-08 to <strong>2007</strong>-07-13,<br />
Saratoga Springs, NY).<br />
Von Toussaint, U. and S. Gori: Echtzeitauswertung von ASDEX<br />
Bolometriedaten. (CODAC Seminar, <strong>2007</strong>-01-23 to <strong>2007</strong>-01-25,<br />
Internationales Begegnungszentrum (IBZ), Garching).<br />
Von Toussaint, U. and P. N. Maya: Molecular Dynamics<br />
Modeling of Chemical Erosion of Carbon Films. (13 th International<br />
Conference on Fusion Reactor Materials (ICFRM-13),<br />
<strong>2007</strong>-12-10 to <strong>2007</strong>-12-14, Nice).<br />
Wagner, D., F. Leuterer, A. Manini, F. Monaco, M. Münich,<br />
H. Schütz, J. Stober, H. Zohm, T. Franke, M. Thumm,<br />
R. Heidinger, I. Danilov, G. Gantenbein, J. Flamm, W. Kasparek,<br />
A. G. Litvak, L. G. Popov, V. O. Nichiporenko, V. E. Myasnikov,<br />
G. G. Denisov, E. M. Tai, E. A. Solyanova and S. A. Malygin:<br />
Commissioning of the second two-frequency gyrotron in the<br />
new ECRH system of ASDEX Upgrade, IRMMW-THz <strong>2007</strong>.<br />
(32 nd International Conference on Infrared and Millimeter<br />
Waves and the 15 th International Conference on Terahertz<br />
Electronics (IRMMW-THz <strong>2007</strong>), <strong>2007</strong>-09-02 to <strong>2007</strong>-09-07,<br />
Cardiff).<br />
Wagner, D., F. Leuterer, J. Stober, A. Manini, F. Monaco,<br />
M. Münich, H. Schütz, H. Zohm, T. Franke, M. Thumm,<br />
R. Heidinger, I. Danilov, G. Gantenbein, J. Flamm, W. Kasparek,<br />
A. G. Litvak, L. G. Popov, V. O. Nichiporenko, V. E. Myasnikov,<br />
G. G. Denisov, E. M. Tai, E. A. Solyanova and S. A. Malygin:<br />
Present status of the new multi-frequency ECRH system for<br />
ASDEX Upgrade. (IEEE <strong>2007</strong> Pulsed Power and Plasma Physics<br />
Conference, <strong>2007</strong>-06-17 to <strong>2007</strong>-06-22, Albuquerque, NM).<br />
Wagner, D., F. Leuterer, J. Stober, A. Manini, F. Monaco,<br />
M. Münich, H. Schütz, H. Zohm, T. Franke, M. Thumm,<br />
R. Heidinger, I. Danilov, G. Gantenbein, J. Flamm, W. Kasparek,<br />
A. G. Litvak, L. G. Popov, V. O. Nichiporenko, V. E. Myasnikov,<br />
G. G. Denisov, E. M. Tai, E. A. Solyanova and S. A. Malygin:<br />
Progress with the new mulit-frequency ECRH system for<br />
ASDEX Upgrade. (19 th Joint Russian-German Meeting on<br />
ECRH and Gyrotrons, <strong>2007</strong>-07-23, Garching).<br />
Wagner, D., F. Leuterer, J. Stober, A. Manini, F. Monaco,<br />
M. Muenich, H. Schütz, H. Zohm, T. Franke, M. Thumm,<br />
R. Heidinger, I. Danilov, G. Gantenbein, J. Flamm, W. Kasparek,<br />
A. G. Litvak, L. G. Popov, V. O. Nichiporenko, V. E. Myasnikov,<br />
G. G. Denisov, E. M. Tai, E. A. Solyanova and S. A. Malygin:<br />
Status of the new multi-frequency ECRH system for ASDEX<br />
Upgrade. (4 th IAEA Meeting on ECRH Physics and Technology<br />
for ITER, <strong>2007</strong>-06-06 to <strong>2007</strong>-06-08, Vienna).
Wagner, F.: Energiepolitik <strong>für</strong> Deutschland aus der Sicht der<br />
Forschung. (Verein deutscher Studenten, <strong>2007</strong>-12-04,<br />
Greifswald).<br />
Wagner, F.: Energy and Physics in Europe. (Energy Symposium,<br />
<strong>2007</strong>-08-31, Helsinki).<br />
Wagner, F.: The EU Stellarator Programme. (NCSX Review,<br />
<strong>2007</strong>-09-14 to <strong>2007</strong>-09-19, Princeton, NJ).<br />
Wagner, F.: Fusion and the physics behind magnetic confinement.<br />
(Physikalisches Kolloquium am <strong>Institut</strong> <strong>für</strong> Theoretische<br />
Physik, <strong>2007</strong>-05-24, Bremen).<br />
Wagner, F.: Fusion Research in Europe. (EPS Energy Meeting,<br />
<strong>2007</strong>-01-15 to <strong>2007</strong>-01-17, Cork).<br />
Wagner, F.: H-mode Transition Physics. (Southwestern<br />
<strong>Institut</strong>e of Physics (SWIP), <strong>2007</strong>-03-30 to <strong>2007</strong>-04-04,<br />
Chengdu).<br />
Wagner, F.: H-modes on W7-AS. (KFKI-Research <strong>Institut</strong>e<br />
for Particle and Nuclear Physics, <strong>2007</strong>-02-06, Budapest).<br />
Wagner, F.: Introduction to High Temperature Plasma Physics<br />
Part II. (WS 2006/<strong>2007</strong>. SS <strong>2007</strong>. Vorlesung, Universität<br />
Greifswald).<br />
Wagner, F.: Opening Session – Welcome Speech. (9 th EUPEN<br />
General Forum EGF <strong>2007</strong>, <strong>2007</strong>-09-06 to <strong>2007</strong>-09-08,<br />
Sant Feliu de Guíxols).<br />
Wagner, F.: Opening Session – Welcome Speech. (GIREP<br />
EPEC Conference, <strong>2007</strong>-08-26 to <strong>2007</strong>-08-31, Opatija).<br />
Wagner, F.: Opening Session – Welcome Speech. (From Quantum<br />
to Cosmos, <strong>2007</strong>-06-10 to <strong>2007</strong>-06-13, Bremen).<br />
Wagner, F.: Physics of and Achievements with the H-mode.<br />
(ITER Reactor Physics Summer School, <strong>2007</strong>-07-16 to<br />
<strong>2007</strong>-07-20, Aix-en-Provence).<br />
Wagner, F.: Physics in Electricity Production. (IPSEC VI<br />
(XXXIX Congress of Polish Physicists), <strong>2007</strong>-09-09 to<br />
<strong>2007</strong>-09-14, Stettin).<br />
Wagner, F.: Die Rolle von Energietechnologien: Was würde<br />
Klimaschutz heute kosten? (Rostocker Wirtschaftsgespräche<br />
– Quo vadis Bundesrepublik?, <strong>2007</strong>-09-25, Rostock).<br />
Wagner, F.: The status of fusion research. (5 th International<br />
Student Conference of the Balkan Physical Union (ISCBPU-5),<br />
<strong>2007</strong>-08-21 to <strong>2007</strong>-08-24, Bodrum).<br />
Lectures<br />
171<br />
Wagner, F.: A quarter-century of H-mode studies. (24 th European<br />
Conference on Controlled Fusion and Plasma Physics,<br />
<strong>2007</strong>-07-02 to <strong>2007</strong>-07-06, Warschau).<br />
Wagner, F.: Stand und Zukunft der Fusionsforschung mit<br />
magnetischem Einschluss. (Physikalisches Kolloquium der<br />
Technische Universität Dresden, <strong>2007</strong>-06-05, Dresden).<br />
Wagner, F.: The Wendelstein Stellarator Line. (Southwestern<br />
<strong>Institut</strong>e of Physics (SWIP), <strong>2007</strong>-03-30 to <strong>2007</strong>-04-04,<br />
Chengdu).<br />
Waldmann, O.: Transport in Magnetized Plasma: Research<br />
for the Development of Fusion Devices. (Pöringer Gespräche:<br />
An interdisciplinary dialogue on complex problem solving,<br />
<strong>2007</strong>-05, Landsberg).<br />
Waldmann, O. and G. Fußmann: Influence of the Langmuir<br />
probe shaft on measuring plasma parameters. (7 th International<br />
Workshop on Electric Probes in Magnetised Plasmas<br />
(IWEP <strong>2007</strong>), <strong>2007</strong>-07-22 to <strong>2007</strong>-07-25, Prague).<br />
Waldmann, O., G. Fußmann and I. Vizgalov: Massenspektrometermessungen<br />
in magnetisierten Plasmen. (DPG AMOP-<br />
Frühjahrstagung, <strong>2007</strong>-03-19 to <strong>2007</strong>-03-23, Düsseldorf).<br />
Wanner, M. and T. Rummel: Study of extended steady state<br />
Operation of the Magnet System of Wendelstein 7-X. (5 th<br />
Technical Meeting on Steady State Operation of Magnetic<br />
Fusion Devices, <strong>2007</strong>-05-14 to <strong>2007</strong>-05-17, Daejeon).<br />
Wegener, L.: Wendelstein 7-X at the transition to assembly.<br />
(Jahrestagung Kerntechnik <strong>2007</strong>, <strong>2007</strong>-05-22 to <strong>2007</strong>-05-24,<br />
Karlsruhe).<br />
Weller, A., K. Y. Watanabe, S. Sakakibara, A. Dinklage,<br />
H. Funaba, J. Geiger, J. H. Harris, R. Preuss, Y. Suzuki, A. Werner,<br />
H. Yamada, W7-AS Team and LHD Team: Extensions of the<br />
International Stellarator Database by High-b Data from W7-AS<br />
and LHD. (Joint Converence of 17 th International Toki Conference<br />
on Physics of Flows and Turbulence in Plasmas and<br />
16 th International Stellarator/Heliotron Workshop, <strong>2007</strong>-10-15<br />
to <strong>2007</strong>-10-19, Ceratopia Toki, Gifu).<br />
Werner, A.: Einschluss überthermischer Ionen in Fusionsplasmen.<br />
(DPG AMOP-Frühjahrstagung, <strong>2007</strong>-03-19 to<br />
<strong>2007</strong>-03-23, Düsseldorf).<br />
Windisch, T., O. Grulke, G. N. Kervalishvili, R. Schneider,<br />
R. Kleiber and T. Klinger: Formation and propagation of<br />
turbulent structures in drift-wave turbulence. (11 th International<br />
Workshop on Plasma Edge Theory in Fusion Devices<br />
(PET 11), <strong>2007</strong>-05-23 to <strong>2007</strong>-05-25, Takayama-city).
Wischmeier, M., A. V. Chankin and D. Coster: Possibilites<br />
and Limitations of the SOLPS code package. (2 nd German<br />
Finish Workshop, <strong>2007</strong>-02-26 to <strong>2007</strong>-02-27, Tarveniemi).<br />
Wischmeier, M., D. Coster, X. Bonnin, A. V. Chankin, M. Groth,<br />
R. Pugno, J. Harhausen, A. Kallenbach, E. Wolfrum and<br />
H. W. Müller: Issues in simulating divertor detachment of ohmic<br />
discharges: examples from ASDEX Upgrade using SOLPS5.0.<br />
(Plasma Boundary Group Meeting, <strong>2007</strong>-09-26, San Diego, CA).<br />
Wischmeier, M., D. Coster, A. Chankin, A. Kallenbach,<br />
H. W. Müller, M. Tsalas and ASDEX Upgrade Team: Simulating<br />
the role of intrinsic carbon impurities in the divertor<br />
detachment of ASDEX Upgrade. (11 th International Workshop<br />
on Plasma Edge Theory in Fusion Devices (PET 11),<br />
<strong>2007</strong>-05-23 to <strong>2007</strong>-05-25, Takayama-city).<br />
Wischmeier, M., A. Kallenbach, A. V. Chankin, D. P. Coster,<br />
R. Dux, J. Harhausen, H. W. Müller, ASDEX Upgrade Team,<br />
M. Groth and X. Bonnin: The influence of high field side<br />
recycling and impurity sources on divertor detachment in<br />
simulations of ohmic discharges of the ASDEX Upgrade<br />
and DIII-D tokamaks. (49 th <strong>Annual</strong> Meeting of the Division<br />
of Plasma Physics, <strong>2007</strong>-11-12 to <strong>2007</strong>-11-16, Orlando, FL).<br />
Wolf, R. and W7-X Team: A Stellarator Reactor based on the<br />
Optimization Criteria of Wendelstein 7-X. (8 th International<br />
Symposium on Fusion Nuclear Technology, <strong>2007</strong>-10-01 to<br />
<strong>2007</strong>-10-05, Heidelberg).<br />
Wolfrum, E.: The current status of the lithium beam diagnostic<br />
at ASDEX Upgrade. (ADAS Workshop, <strong>2007</strong>-10-10<br />
to <strong>2007</strong>-10-13, Schloss Ringberg, Tegernsee).<br />
Wolfrum, E.: Kernfusion. (Abschlussveranstaltung <strong>für</strong> das EU<br />
Projekt “Pallas Athene”, <strong>2007</strong>-10-11 to <strong>2007</strong>-10-12, Berlin).<br />
Wolfrum, E. and S. Schweinzer: Grundlagen des Fusionsreaktors.<br />
(SS 2207. Vorlesung, Universität Wien).<br />
Worbs, P., B. Schwarz, H. Maier and H. Bolt: TiC coatings<br />
as wetting promoter for optimizing carbon/copper brazed<br />
joints in high heat flux components. (European Congress<br />
and Exhibition on Advanced Materials and Processes<br />
(EUROMAT <strong>2007</strong>), <strong>2007</strong>-09-10 to <strong>2007</strong>-09-13, Nürnberg).<br />
Woskov, P. P., H. Bindslev, S. B. Korsholm, F. Leipold, F. Meo,<br />
P. K. Michelsen, S. Michelsen, S. K. Nielsen, E. L. Tsakadse,<br />
E. Westerhof, H. Oosterbeek, J. Hoekzema, F. Leuterer and<br />
D. Wagner: Gyrotron collective Thomson scattering of fast<br />
ions in TEXTOR and ASDEX Upgrade. (IEEE <strong>2007</strong> Pulsed<br />
Power and Plasma Physics Conference, <strong>2007</strong>-06-17 to<br />
<strong>2007</strong>-06-22, Albuquerque, NM).<br />
Lectures<br />
172<br />
Wünderlich, D. and NNBI Team: Rechnungen zum Einfluss<br />
von Bias und Magnetfeldern auf die Randschicht in einer<br />
Quelle <strong>für</strong> negative Wasserstoffionen. (DPG AMOP-Frühjahrstagung,<br />
<strong>2007</strong>-03-19 to <strong>2007</strong>-03-23, Düsseldorf).<br />
Xanthopoulos, P., F. Jenko, F. Merz and T. Görler: Gyrokinetic<br />
Simulations of the ITG mode for the Optimized<br />
Stellarator Wendelstein 7-X. (12 th European Fusion Theory<br />
Conference, <strong>2007</strong>-09-23 to <strong>2007</strong>-09-27, Madrid).<br />
Xanthopoulos, P., F. Jenko, F. Merz and T. Görler: Gyrokinetic<br />
Simulations of Microinstabilities for the Stellarator<br />
Wendelstein 7-X. (3 rd IAEA Technical Meeting on the Theory<br />
of Plasma Instabilties, <strong>2007</strong>-03-26 to <strong>2007</strong>-03-28, York).<br />
Xanthopoulos, P., F. Jenko, F. Merz, T. Görler and D. Mikkelsen:<br />
Gyrokinetic Turbulence Simulations for Stellarators. (49 th <strong>Annual</strong><br />
APS Division of Plasma Physics Meeting, <strong>2007</strong>-11-12 to<br />
<strong>2007</strong>-11-16, Orlando, FL).<br />
Yakovenko, Y., A. Weller, A. Werner, S. Zegenhagen, O. P. Fesenyuk<br />
and Y. Kolesnichenko: Effect of the Three-Dimensionality<br />
of the Magnetic Geometry on Alfvén Instabilities in Stellarators.<br />
(10 th IAEA Technical Meeting on Energetic Particles in<br />
Magnetic Confinement Systems, <strong>2007</strong>-10-08 to <strong>2007</strong>-10-10,<br />
Kloster Seeon).<br />
Yao, Z., A. Suzuki, D. Levchuk, T. Chikada, T. Tanaka, T. Muroga<br />
and T. Terai: Hydrogen Permeation through Steel coated<br />
with Erbium Oxide by Sol-gel Method. (13 th International<br />
Conference on Fusion Reactor Materials (ICFRM-13),<br />
<strong>2007</strong>-12-10 to <strong>2007</strong>-12-14, Nice).<br />
Yao, Z., A. Suzuki, D. Levchuk and T. Terai: Hydrogen permeation<br />
through steel coated with silicon carbide. (8 th International<br />
Conference on Tritium Science and Technology<br />
(ICTST8), <strong>2007</strong>-09-16 to <strong>2007</strong>-09-21, Rochester, NY).<br />
You, J. H.: Application of a fibre-reinforced copper matrix<br />
composite cooling tube to a water cooled mono-block divertor<br />
component: A design study. (13 th International Conference<br />
on Fusion Reactor Materials (ICFRM-13), <strong>2007</strong>-12-10 to<br />
<strong>2007</strong>-12-14, Nice).<br />
You, J. H.: Engineering application of shakedown analysis<br />
to a composite structures reinforced with fibrous metal<br />
matrix composites. (Werkstoffmechanisches Kolloqium,<br />
<strong>2007</strong>-11-08 to <strong>2007</strong>-11-09, RWTH Aachen).<br />
You, J. H.: Integrated modelling approaches on multi-scales<br />
for failure analysis of a composite structure with fibre-reinforced<br />
metal matrix composite. (GKSS Workshop “Material<br />
Models”, <strong>2007</strong>-06-11 to <strong>2007</strong>-06-12, Hamburg).
You, J. H.: Integrated modelling approaches on multi-scales<br />
for failure analysis of a composite structure with fibre-reinforced<br />
metal matrix composite. (MPA <strong>Institut</strong>, <strong>2007</strong>-06-21,<br />
Universität Stuttgart).<br />
You, J. H.: Integrated modelling approaches on multi-scales<br />
for failure analysis of a composite structure with fibre-reinforced<br />
metal matrix composite. (Werkstoffmechanisches<br />
Kolloquium, <strong>2007</strong>-10-05, RWTH Aachen).<br />
You, J. H.: Schichtmechanik. (WS 2006/<strong>2007</strong>. Vorlesung<br />
“Dünne Schichten”, Technische Universität München).<br />
Yu, Q., S. Günter, Y. Kikuchi and K. H. Finken: Nonlinear<br />
calculation of the penetration threshold of the error field.<br />
(Biennial Workshop “Stochasticity in Fusion Plasmas”<br />
(SFP <strong>2007</strong>), <strong>2007</strong>-03-05 to <strong>2007</strong>-03-07, Jülich).<br />
Yu, Q., M. Hölzl, S. Günter and K. Lackner: Theoretical Studies<br />
on Heat Diffusion across Magnetic Island and Local Stochastic<br />
Magnetic Field. (Biennial Workshop “Stochasticity in<br />
Fusion Plasmas” (SFP <strong>2007</strong>), <strong>2007</strong>-03-05 to <strong>2007</strong>-03-07, Jülich).<br />
Zacharias, T., U. Fantz and NNBI-Team: Ortsaufgelöste H α<br />
Dopplerspektroskopie an einem Wasserstoffionenstrahl.<br />
(DPG AMOP-Frühjahrstagung, <strong>2007</strong>-03-19 to <strong>2007</strong>-03-23,<br />
Düsseldorf).<br />
Zhang, D., L. Giannone, O. Grulke, M. Piechotka, T. Windisch,<br />
A. Stark and T. Klinger: Investigation of the Neutral Gas Pressure<br />
Effect on the Metal Resistive Bolometer. (PLASMA <strong>2007</strong> –<br />
International Conference on Research and Applications of<br />
Plasmas combined with the 4 th German-Polish Conference<br />
on Plasma Diagnostics for Fusion and Applications and the<br />
6 th French-Polish Seminar on Thermal Plasma in Space and<br />
Laboratory, <strong>2007</strong>-10-16 to <strong>2007</strong>-10-19, Greifswald).<br />
Lectures<br />
173
ASDEX Upgrade Team<br />
J. Adamek*, C. Angioni, G. Antar, C. V. Atanasiu*, M. Balden,<br />
W. Becker, K. Behler, K. Behringer, A. Bergmann, T. Bertoncelli,<br />
R. Bilato, V. Bobkov, O. Bottino, M. Brambilla, F. Braun,<br />
M. Brüdgam, A. Buhler, A. Chankin, I. Classen, G. Conway,<br />
D. P. Coster, P. de Marné, S. Dietrich, R. D’Inca, R. Drube,<br />
R. Dux, T. Eich, K. Engelhardt, H.-U. Fahrbach, L. Fattorini*,<br />
J. Fink, R. Fischer, A. Flaws, M. Foley*, C. Forest*,<br />
J. C. Fuchs, K. Gál*, M. García Muñoz, M. Gemisic Adamov,<br />
L. Gianonne, T. Görler, S. Gori, S. da Graca*, H. Greuner,<br />
O. Gruber, A. Gude, S. Günter, G. Haas, J. Harhausen,<br />
B. Heinemann, A. Herrmann, N. Hicks, J. Hobirk, M. Hölzl,<br />
D. Holtum, C. Hopf, L. Horton, M. Huart, V. Igochine, F. Jenko,<br />
A. Kallenbach, S. Kálvin*, O. Kardaun, M. Kaufmann,<br />
M. Kick, A Kirk, H.-J. Klingshirn, G. Kocsis*, H. Kollotzek,<br />
C. Konz, K. Krieger, T. Kurki-Suonio*, B. Kurzan, K. Lackner,<br />
P. T. Lang, B. Langer, P. Lauber, M. Laux, F. Leuterer,<br />
J. Likonen*, L. Liu, A. Lohs, A. Lyssoivan*, C. Maggi,<br />
A. Manini, K. Mank, M.-E. Manso*, M. Mantsinen,<br />
M. Maraschek, P. Martin*, M. Mayer, P. McCarthy*,<br />
K. McCormick, H. Meister, F. Meo*, P. Merkel, R. Merkel,<br />
V. Mertens, F. Merz, H. Meyer*, A. Mlynek, F. Monaco,<br />
H. W. Müller, M. Münich, H. Murmann, G. Neu, R. Neu,<br />
J. Neuhauser, B. Nold*, J.-M. Noterdaeme, G. Pautasso,<br />
G. Pereverzev, E. Poli, M. J. Püschel, T. Pütterich, R. Pugno,<br />
E. Quigley*, I. Radivojevic, G. Raupp, M. Reich, B. Reiter,<br />
T. Ribeiro*, R. Riedl, V. Rohde, J. Roth, M. Rott, F. Ryter,<br />
W. Sandmann, J. Santos*, K. Sassenberg, A. Scarabosio,<br />
G. Schall, H.-B. Schilling, J. Schirmer, A. Schmid, K. Schmid,<br />
W. Schneider, G. Schramm, R. Schrittwieser*, W. Schustereder,<br />
J. Schweinzer, S. Schweizer, B. Scott, U. Seidel, M. Sempf,<br />
F. Serra*, M. Sertoli, A. Sigalov, A. Silva*, A. C. C. Sips,<br />
E. Speth, A. Stäbler, K.-H. Steuer, J. Stober, B. Streibl,<br />
E. Strumberger, W. Suttrop, G. Tardini, C. Tichmann,<br />
W. Treutterer, C. Tröster, L. Urso, E. Vainonen-Ahlgren*,<br />
P. Varela*, L. Vermare, D. Wagner, C. Wigger, M. Wischmeier,<br />
E. Wolfrum, E. Würsching, D. Yadikin, Q. Yu, D. Zasche,<br />
T. Zehetbauer, M. Zilker, H. Zohm.<br />
ECRH-Team<br />
A. Arnold, B. Berndt, P. Brand, H. Braune, G. Dammertz,<br />
V. Erckmann, J. Flamm, G. Gantenbein, M. Grünert,<br />
R. Heidinger, F. Hollmann, M. Huber, H. Hunger, S. Illy, J. Jin,<br />
L. Jonitz, W. Kasparek, S. Kern, M. Krämer, H. Kumric,<br />
R. Lang, H. P. Laqua, C. Lechte, W. Leonhardt, O. Mangold,<br />
D. Mellein, G. Michel, F. Müller, R. Munk, F. Noke, B. Piosczyk,<br />
B. Plaum, S. Prets, O. Prinz, F. Purps, T. Rzesnicki,<br />
U. Saller, P. Salzmann, K.-H. Schlüter, M. Schmid, T. Schulz,<br />
W. Spiess, M. Stoner, U. Stroth, J. Szczesny, M. Thumm,<br />
P. Uhren, J. Weggen, M. Weißgerber, D. Wimmer, C. Zöller.<br />
Teams<br />
175<br />
ICRF-Team<br />
S. Assas, W. Becker, V. Bobkov, F. Braun, R. D’Incà, B. Eckert,<br />
R. Euteneier, H. Faugel, F. Fischer, L. Liu, M. Mantsinen*,<br />
J.-M. Noterdaeme, A. Onyshchenko*, M. Prechtl, T. Sachse,<br />
G. Siegl, H. Wehling, C. Wiesmann, E. Würsching, I. Zammuto.<br />
NBI-Team<br />
P. Agostinetti*, M. Berger, S. Christ-Koch, H. Falter, U. Fantz,<br />
P. Franzen, M. Fröschle, R. Gutser, B. Heinemann, D. Holtum,<br />
C. Hopf, T. Jiang*, R. Kairys, M. Kick, W. Kraus, S. Leyer,<br />
C. Martens, P. McNeely, R. Nocentini, S. Obermayer, R. Riedl,<br />
P. Rong, N. Rust, J. Schäffler, R. Schroeder, J. Sielanko*,<br />
E. Speth, A. Stäbler, P. Turba, D. Wünderlich.<br />
NNBI-Team<br />
P. Agostinetti*, M. Berger, S. Christ-Koch, H. Falter, U. Fantz,<br />
P. Franzen, M. Fröschle, R. Gutser, B. Heinemann, D. Holtum,<br />
T. Jiang*, W. Kraus, S. Leyer, C. Martens, P. McNeely,<br />
R. Nocentini, S. Obermayer, R. Riedl, J. Sielanko*, E. Speth,<br />
P. Turba, D. Wünderlich.<br />
W7-X Team<br />
G. Adam, J. Ahmels, T. Andreeva, M. Balden, K. Bald-Soliman,<br />
J. Baldzuhn, M. Banduch, H. Bau, Ch. Baylard*, W. Becker,<br />
M. Bednarek, D. Beiersdorf, A. Benndorf, M. Bensouda-<br />
Korachi, A. Berg, N. Berger, A. Bergmann, P. Biedunkiewicz,<br />
R. Binder, D. Birus, T. Bluhm, R. Blumenthal, H. Bolt,<br />
J. Boscary, H.-S. Bosch, B. Böswirth, A. Braatz, R. Brakel,<br />
H.-J. Bramow, T. Bräuer, H. Braune, T. Broszat, B. Brucker,<br />
R. Brüderl, R. Burhenn, V. Bykov, J. Cantarini*, A. Cardella*,<br />
D. Chauvin*, P. Chen, W. Chen, G. Croari*, P. Czarkowski*,<br />
M. Czerwinski, W. Dänner*, J. Dedic, C. Dhard, A. Dinklage,<br />
A. Domscheidt, A. Dübner, A. Dudek, H. Dutz, B. Eckert,<br />
P. v. Eeten, K. Egorov, G. Ehrke, H. Eixenberger, M. Endler,<br />
V. Erckmann, H. Faugel, W. Fay, J.-H. Feist, J. Fellinger,<br />
A. Friedrich, F. Fischer, N. Fuchs, F. Füllenbach, G. Gliege,<br />
S. Gojdka, M. Gottschewsky, H. Greuner, H. Greve, P. Grigull,<br />
H. Grote, D. Grünberg, H. Grunwald, L. Guerrini*, D. Gustke,<br />
M. Haas, N. Hajnal, E. Hahnke, K.-H. Hanausch, A. Hansen,<br />
H.-J. Hartfuß, D. Hartmann, D. Hathiramani, D. Haus,<br />
P. Heimann, B. Hein, B. Heinemann, K. Henkelmann, C. Hennig,<br />
U. Herbst, D. Hermann, F. Herold, K. Hertel, D. Hildebrandt,<br />
M. Hirsch, A. Hölting, D. Holtum, A. Holtz, R. Holzthüm,<br />
M. Huart, H. Hübner, A. Hübschmann, F. Hurd*, M. Ihrke,<br />
N. Jaksic, D. Jassmann, H. Jenzsch, A. John, L. Jonitz, S. Jung,<br />
A. Junge, P. Junghanns*, J. Kallmeyer, U. Kamionka,<br />
M. Kammerloher, M. Kick, J. Kißlinger*, T. Kluck, C. Klug,<br />
M. Kluger, J. Knauer, F. Koch, R. König, T. Koppe, M. Köppen,
P. Kornejev, R. Krampitz, R. Krause, U. Krybus, M. Krychowiak,<br />
G. Kühner, F. Kunkel, B. Kursinski, B. Kurzan, A. Kus,<br />
H. Laqua, H. Laqua, M. Laux, H. Lentz, M. Lewerentz, C. Li,<br />
S. Lindig, J. Lingertat*, A. Lorenz, Jo. Maier, Jü. Maier,<br />
C. Martens, G. Matern, P. McNeely, B. Mendelevitch, G. Michel,<br />
B. Missal, H. Modrow, St. Mohr, L. Mollwo, T. Mönnich,<br />
A. Müller, E. Müller, I. Müller, J. Müller, K. Müller, M. Müller,<br />
H. Murmann, M. Nagel, D. Naujoks, U. Neumann, U. Neuner,<br />
U. Nielsen*, M. Nitz, F. Noke, J. M. Noterdaeme, S. Obermayer,<br />
A. Okkenga-Wolf, A. Opitz, E. Pasch, A. Peacock, B. Petersen-<br />
Zarling, B. Petzold, K. Pfefferle, M. Pietsch, D. Pilopp, S. Pingel,<br />
H. Pirsch, R. Pollner, R. Preuß*, F. Purps, D. Rademann,<br />
T. Rajna *, H. Rapp*, J. Reich, L. Reinke, T. Richert, R. Riedl,<br />
K. Riße, M. Rott, K. Rummel, Th. Rummel, N. Rust, N. Rüter,<br />
J. Sachtleben, P.G. Sanchez*, J. Schacht, F. Schauer,<br />
F. Scherwenke, D. Schinkel, R.-C. Schmidt, M. Schneider,<br />
W. Schneider, M. Schrader, R. Schroeder, M. Schröder,<br />
P. Scholz, U. Schultz, A. Schütz, E. Schwarzkopf, S. Schweizer,<br />
Ch. von Sehren, K.-U. Seidler, G. Siegl, J. Simon-Weidner,<br />
W. Sinz, B. Sitkowski, M. Smirnow, E. Speth, A. Spring,<br />
A. Stäbler, R. Stadler, F. Starke, M. Steffen, B. Streibl,<br />
M. Sochor, L. Sonnerup*, A. Tereshchenko, D. Theuerkauf,<br />
S. Thiel, H. Tittes, R. Tivey, P. Turba, H. Thomsen, V. Tomarchio*,<br />
P. Uhren, S. Valet, A. Vetterlein, H. Viebke, T. Vierle,<br />
R. Vilbrandt, O. Volzke, S. Vorbrugg, A. Vorköper, F. Wagner,<br />
M. Wanner, S. Weber, L. Wegener, M. Weißgerber, A. Weller,<br />
J. Wendorf, S. Wendorf*, U. Wenzel, A. Werner, K.-D. Wiegand,<br />
M. Winkler, R. Wolf, M. Ye, D. Zacharias, G. Zangl, F. Zeus,<br />
D. Zhang, M. Zilker, K. Zimmermann.<br />
*external authors<br />
Teams<br />
176
Appendix
Stuttgart A8<br />
Appendix<br />
How to reach <strong>IPP</strong> in Garching<br />
Garmisch<br />
Lindau<br />
A9 6<br />
A9 5<br />
A9 9<br />
Nürnberg<br />
Exit<br />
Garching<br />
Nord<br />
S1<br />
A9<br />
U6<br />
178<br />
Neufahrn<br />
München<br />
Bus 690<br />
Garching<br />
S8<br />
By car:<br />
Exit Garching-Nord on the<br />
Autobahn A9 München-Nürnberg,<br />
then follow the signs “Forschungsinstitute”.<br />
A8<br />
Garching-<br />
Research Center<br />
Passau<br />
A9 4<br />
Salzburg<br />
By public transport:<br />
Any S metro from Munich Main Station to Marienplatz,<br />
metro U6 to Garching-Forschungszentrum;<br />
or from Airport Munich: S1 to Neufahrn, then bus 690<br />
to "Garching Forschungszentrum" (only on weekdays).<br />
A92<br />
A9 9<br />
Deggendorf<br />
A9 9<br />
Munich Airport
Direction<br />
Rostock<br />
Appendix<br />
How to reach Greifswald Branch <strong>Institut</strong>e of <strong>IPP</strong><br />
Exit<br />
Greifswald<br />
BAB<br />
A20<br />
B96<br />
Exit<br />
Gützkow<br />
DB<br />
Greifswald<br />
179<br />
B105<br />
Direction<br />
Neubrandenburg<br />
Berlin<br />
Greifswald<br />
Centre<br />
B109<br />
DB<br />
Exit<br />
Schönwalde<br />
By air and train:<br />
Via Berlin: from Berlin Tegel Airport by bus “JetExpressBus” to Hauptbahnhof (central station),<br />
by train to Greifswald.<br />
Via Hamburg: from the airport to main Railway Station, by train to Greifswald main station.<br />
By bus:<br />
From Greifswald-Railway Station by bus No. 2 or 3 to the “Elisenpark” stop.<br />
By car:<br />
Via Berlin, Neubrandenburg to Greifswald or via Hamburg, Lübeck, Stralsund to Greifswald,<br />
in Greifswald follow the signs “<strong>Max</strong>-<strong>Planck</strong>-<strong>Institut</strong>”.<br />
L35<br />
B109<br />
Direction<br />
Anklam
Appendix<br />
Organisational structure<br />
of <strong>Max</strong>-<strong>Planck</strong>-<strong>Institut</strong> <strong>für</strong> <strong>Plasmaphysik</strong><br />
180
<strong>Max</strong>-<strong>Planck</strong>-<strong>Institut</strong><br />
<strong>für</strong> <strong>Plasmaphysik</strong>