Nonlinear kinetic simulations of stimulated Brillouin scattering

Abstract

Numerical simulation results of stimulated Brillouin scattering (SBS) using HERCULES [H. X. Vu, J. Comput. Phys. 124, 417 (1996)], an adiabatic fluid-electron particle-in-cell (PIC) code, are presented. The results of these PIC simulations are compared against fluid simulations, and good agreement is obtained for sufficiently weak laser intensities. When the laser intensity is sufficiently strong for ion trapping to be significant, PIC and fluid simulations differ substantially. The trapping time and nonlinear frequency shift obtained in the PIC simulations are in good agreement with analytical predictions. The SBS reflectivity is shown to be very sensitive to frequency mismatch between the light wave used to seed the instability and the incident laser.