Temporal Evolution of Self-Modulated Laser Wakefields Measured by Coherent Thomson Scattering.
NAVAL RESEARCH LAB WASHINGTON DC BEAM PHYSICS BRANCH
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Coherent Thomson scattering of a picosecond probe laser was used to measure the time evolution of plasma wakefields produced by a high intensity laser pulse 4 x 10exp 18 Wcm2 in an underdense plasma n sub e approx 10exp 19cc in the Self Modulated Laser Wakefield Accelerator configuration. Plasma wakefields are observed to last for approximately 50 psec. Ion acoustic waves, generated by the decay of the plasma wakefield, were measured to have a duration of approximately 50 psec. These observations are consistent with the decay of large amplitude plasma waves due to the modulational instability and the enhancement of the scattered signal from plasma channel formation.
- Plasma Physics and Magnetohydrodynamics