A Brief Introduction to Space Plasma Physics.pdf - Institute of ...
A Brief Introduction to Space Plasma Physics.pdf - Institute of ... A Brief Introduction to Space Plasma Physics.pdf - Institute of ...
• The change in the direction of the magnetic field along a field line can cause motion. – The curvature of the magnetic field line introduces a drift motion. • As particles move along the field they undergo centrifugal acceleration. 2 r F mv R nˆ • R c is the radius of curvature of a field line ( = −( bˆ ⋅∇) bˆ ) where Rc r B bˆ = , nˆ is perpendicular to B r and points away from the center B of curvature, v is the component of velocity along B r r u c = mv • Curvature drift can cause currents. = c Rˆ c r B× ( bˆ ⋅∇) bˆ 2 2 ˆ qB 2 r mv B× n = − 2 R qB c
• The Concept of the Guiding Center v r – Separates the motion ( ) of a particle into motion perpendicular ( ) and parallel ( v ) to the magnetic field. v ⊥ – To a good approximation the perpendicular motion can consist of a drift ( ) and the gyro-motion ( ) r v = r v v D – Over long times the gyro-motion is averaged out and the particle motion can be described by the guiding center motion consisting of the parallel motion and drift. This is very useful for distances l such that ρ c l
- Page 1 and 2: ESS 200C - Space Plasma Physics Win
- Page 3 and 4: Space Plasma Physics • Space phys
- Page 5 and 6: - Galileo theorized that aurora is
- Page 7 and 8: The Plasma State • A plasma is an
- Page 9 and 10: • B acts to change the motion of
- Page 11: • The electric field can modify t
- Page 16 and 17: • Maxwell’s equations - Poisson
- Page 18 and 19: • Maxwell’s equations in integr
- Page 20 and 21: • For a coordinate in which the m
- Page 22 and 23: B r • The force is along and away
- Page 24: - As particles bounce they will dri
- Page 27 and 28: The Properties of a Plasma • A pl
- Page 29 and 30: • For monatomic particles in equi
- Page 31 and 32: • What makes an ionized gas a pla
- Page 34 and 35: • The plasma frequency - Consider
- Page 36 and 37: • A note on conservation laws - C
- Page 38 and 39: - Momentum equation r ∂us r r r r
- Page 40 and 41: • Energy equation ∂ ( ∂t 1 2
- Page 43 and 44: - Often the last terms on the right
- Page 45 and 46: F B • Magnetic pressure and tensi
- Page 47 and 48: •Some elementary wave concepts -F
- Page 49 and 50: • When the dispersion relation sh
- Page 51 and 52: - Incompressible Alfvén waves •
- Page 53 and 54: 1 2 2 C ⎛ B ⎞ A ⎜ ⎟ ⎝ µ
- Page 55 and 56: - Continuity - Momentum - Equation
- Page 57 and 58: • The fluid velocity must be alon
- Page 59: - Arbitrary angle between k r and B
• The change in the direction <strong>of</strong> the magnetic field<br />
along a field line can cause motion.<br />
– The curvature <strong>of</strong> the magnetic field line introduces a drift<br />
motion.<br />
• As particles move along the field they undergo centrifugal<br />
acceleration.<br />
2<br />
r<br />
F<br />
mv<br />
R<br />
nˆ<br />
• R c<br />
is the radius <strong>of</strong> curvature <strong>of</strong> a field line ( = −(<br />
bˆ<br />
⋅∇)<br />
bˆ<br />
)<br />
where<br />
Rc<br />
r<br />
B<br />
bˆ = , nˆ is perpendicular <strong>to</strong> B r<br />
and points away from the center<br />
B<br />
<strong>of</strong> curvature, v is the component <strong>of</strong> velocity along B r<br />
r<br />
u<br />
c<br />
=<br />
mv<br />
• Curvature drift can cause currents.<br />
=<br />
c<br />
Rˆ<br />
c<br />
r<br />
B×<br />
( bˆ<br />
⋅∇)<br />
bˆ<br />
2 2<br />
ˆ<br />
qB<br />
2<br />
r<br />
mv B×<br />
n<br />
= −<br />
2<br />
R qB<br />
c
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