Effect of wave damping on the nonlinear saturation of stimulated Raman scattering in a finite homogeneous plasma

Abstract

A question of stationarity of a nonlinear saturated regime of stimulated Raman backscattering in a finite homogeneous plasma is considered. Slowly varying envelope equations with the damping and the nonlinear frequency shift terms included are treated numerically. It is demonstrated by a space-time simulation of these equations that the variation in the damping rate drives the system through various dynamical regimes (from steady-state to chaotic). A simplified, space-only approach, based on the use of a numerical shooting method was applied to calculate the critical damping values corresponding to transitions between stationary and nonstationary saturated regimes. The corresponding bifurcation diagrams that enable prediction of the type of asymptotic behaviour of Raman instability are obtained and discussed.