Investigation of Stimulated Brillouin Scattering in Laser-Plasma Interactions

TL;DR

This study uses numerical simulations to analyze Stimulated Brillouin Scattering in laser-plasma interactions, focusing on how different frequencies and plasma conditions affect instability growth and damping.

Contribution

It provides new insights into the impact of incident wave frequency and plasma temperature ratios on SBS instability growth and damping through detailed Vlasov equation simulations.

Findings

Higher incident wave frequencies reduce instability growth rates.

Plasma heating causes damping of SBS instability over time.

Ion acoustic wave damping varies with ion-to-electron temperature ratio.

Abstract

In this paper, we present our numerical simulation results on the Stimulated Brillouin Scattering (SBS) with injection of an ordinary mode (O-mode) electromagnetic wave (our pump wave) with frequencies 70 GHz and 110 GHz. Solving the Fourier transformed Vlasov equation in the velocity space, creates a profile for distribution function. Time evolution of the distribution function is investigated as well. Considering an average density for plasma fusion (n_{0} ~ 10^{19} m^{-3}), we gain a profile for density. Then two-dimensional instability rate for SBS is obtained. So, the fluctuation of distribution function affects density and again density affects instability rate. Increasing the incident light wave frequency causes the instability growth rate to decrease. Time evolution shows a clear damping for instability rate since the pump wave's energy is absorbed in plasma (plasma heating). Furthermore, changing Landau damping for ion acoustic waves (IAW) by changing ion-to-electron temperature ratio is presented as well, because this damping is more dominant in high temperatures.