Stimulated Brillouin scattering off nonlinear ion acoustic waves

The influence of nonlinear ion acoustic waves on the stimulated Brillouin backscattering process is investigated with the help of the hydrodynamic description of the ion fluid. Numerical calculations were systematically performed for a wide range of relevant parameters in the presence of an ideal plasma. It is shown that the scaling of steady-state solutions due to spatially amplified scattering deviates significantly from the theory where only linearized ion acoustic waves are considered. An analytic approach using harmonic expansion confirms the similarity parameters found numerically. The significance of kinetic effects, such as anomalous heat transport due to fast ions and ion trapping in the presence of weakly damped ion waves, is also studied using particle simulations.