Suppression of Stimulated Raman Scattering and Hot Electrons Generation due to Langmuir Decay Instability Cascade and Langmuir Collapse

TL;DR

This paper demonstrates through Vlasov simulations that Langmuir decay instability cascade and Langmuir collapse significantly suppress backward stimulated Raman scattering and hot electron generation in plasmas, offering a new control mechanism.

Contribution

First simulation-based demonstration of how LDI cascade and Langmuir collapse suppress BSRS and hot electrons, with insights into plasma species and ion ratios.

Findings

LDI cascade reduces BSRS reflectivity.

Langmuir collapse occurs alongside LDI cascade.

Adjusting plasma species and ion ratios enhances suppression.

Abstract

Backward stimulated Raman scattering (BSRS) with Langmuir decay instability (LDI) and Langmuir collapse has been researched by Vlasov simulation for the first time. The decay productions of LDI cascade and their evolution with time is clearly demonstrated, which occurs simultaneously with Langmuir collapse. The BSRS reflectivity will be decreased largely through LDI cascade and Langmuir collapse. In CH plasmas, when $T_i/T_e=1/3$, the Landau damping of the slow ion-acoustic wave (IAW) is lower than that in H plasmas. Therefore, the BSRS can be further suppressed through LDI cascade by the way of controlling the species of plasmas and ions ratio. These results give an effective mechanism to suppress the BSRS and hot electrons generation.