Terry Kammash - NASA's Institute for Advanced Concepts

Terry Kammash - NASA's Institute for Advanced Concepts Terry Kammash - NASA's Institute for Advanced Concepts

niac.usra.edu
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10.07.2015 Views

Future Laser DevelopmentOscillatorCleaner(10 6 contrast)RegenerativeAmplifier4-passAmplifier2-passAmplifierHigh-PowerAmplifierEnergy Pulse width RepetitionRate1 nJ 10-15 fs 80 Mhz1 mJ 15 fs 10 Hz100 mJ 350 ps 10 Hz1-1.5 J7-10 J350 psCurrent Hercules350 ps10 Hz0.1 Hz50 J 350ps 0.1 HzCompressedOutputN/AN/AN/A20-30 TW@ 25 fs100-200 TW@ 25-40 fs1 PW @ 30-40 fs

Proton Acceleration Summary• Simulation and experiment support proton acceleration at thelaser-irradiated side of the target of a 4 MeV beam, on the backof the underdense plasma under these conditions.• And a 12 MeV beam from the rear-surface of Al due torecirculation sheath enhancement.• Beam spectrum has bands of energies due to “ion fronts.”• Beam profile smoothes out as initial target conductivityincreases.• Filamentation and structures similar to the electron simulationby Gremillet et. al have been observed.• Demonstrated beam profile modification with modest geometry,and enhancement of number at the maximum energy achievedby initial target geometry and surface conditions• CR-39 response is highly non-linear when scanned optically.• By using a highly absorptive material we have increased thenumber of maximum energy protons without sacrificing beamquality. No imprint of LB on beam profile, unlike Roth et. al• New 30 fs laser has produced 10 21 W/cm 2 on target in a 1 micronspot, expect high efficiency acceleration

Proton Acceleration Summary• Simulation and experiment support proton acceleration at thelaser-irradiated side of the target of a 4 MeV beam, on the backof the underdense plasma under these conditions.• And a 12 MeV beam from the rear-surface of Al due torecirculation sheath enhancement.• Beam spectrum has bands of energies due to “ion fronts.”• Beam profile smoothes out as initial target conductivityincreases.• Filamentation and structures similar to the electron simulationby Gremillet et. al have been observed.• Demonstrated beam profile modification with modest geometry,and enhancement of number at the maximum energy achievedby initial target geometry and surface conditions• CR-39 response is highly non-linear when scanned optically.• By using a highly absorptive material we have increased thenumber of maximum energy protons without sacrificing beamquality. No imprint of LB on beam profile, unlike Roth et. al• New 30 fs laser has produced 10 21 W/cm 2 on target in a 1 micronspot, expect high efficiency acceleration

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