Nonstationarity of stimulated Raman scattering in a homogeneous plasma slab

Abstract

Nonstationarity of stimulated Raman backscattering in a finite homogeneous plasma slab is examined. Slowly varying envelope equations are analyzed taking into account a damping and a convection of an electron plasma wave, with a nonzero source boundary condition assumed. The linear analysis method is used for examination of stability of saturated stationary amplitude solutions. When linear wave damping is sufficiently small or absent, these solutions are spatially periodic and appear linearly unstable to small perturbations. However, a direct numerical simulation of the backscattering process in a lossless case shows that the system tends to quasistationary state with maximum reflectivity (R → 1). If the electron plasma wave damping exceeds a certain critical value, a spatially aperiodic solution raises and the Raman backscattering process becomes stable.