Suppression of stimulated Raman side-scattering of a laser in a plasma in presence of co-propagating electron beam

摘要

The growth of stimulated Raman side-scattering of a laser beam propagating in the plasma may be influenced by the presence of co-propagating electron beam. The laser beam excites a pair of plasma wave and side-scattered electromagnetic wave. The side-scattered wave and pump wave couple together and exert a ponderomotive force on beam and plasma electrons which intern enhances the amplitude of plasma wave. The density perturbation in the plasma due to plasma wave couple nonlinearly with pump wave and excite a nonlinear current responsible for the growth of side-scattered electromagnetic wave. The phase matching between plasma wave and electron beam controls the growth of Raman process. Raman process saturates when bounce frequency of beam electrons exceeds the growth rate.