Random Density Inhomogeneities and Focusability of the Output Pulses for Plasma-based Powerful Backward Raman Amplifiers
Authors: A.A. Solodov, V.M. Malkin, and N.J. Fisch
Date of PPPL Report: January 2003
Published in: Physics of Plasmas 10 (June 2003) No. 6, 2540-2544
Random plasma density inhomogeneities may defocus the output pulses of powerful backward Raman amplifiers (BRA). Because of ultra-high intensities of even non-focused BRA outputs, such distortions, if occur, are then difficult to correct. We derive a simple expression for the largest BRA length for which the output pulse focusability is not yet spoiled. Interestingly, this limitation does not depend on the pump laser intensity. We also note a useful effect of plasma inhomogeneities that might help to suppress premature pump backscattering by thermal noise.