57 / 2026-03-24 10:52:25

Kinetic simulation of laser plasma instabilities including collisional effects on sub-nanosecond timescales

laser plasma instabilities, collisional effects, energy coupling, inertial confinement fusion

激光与粒子束聚变、磁驱动聚变 > 激光聚变物理

Efficient laser-target energy coupling is of critical importance in inertial confinement fusion (ICF), where collisional absorption and laser-plasma instabilities (LPIs) compete to determine overall energy deposition. However, few studies have simultaneously captured both collisional absorption and LPIs, particularly in the kinetic regime. In this work, we develop a code capable of performing unified kinetic simulations of these two kinds of competing processes on sub‑nanosecond timescales. The code builds upon a previous one-dimensional particle-mesh code PM1D¹, which was originally designed to simulate only LPIs, by self-consistently incorporating various collisional effects. It integrates collisional absorption and collisional damping terms into the electromagnetic wave equation and the motion equations for electrons and ions, coupled with the temperature evolution equations that describe energy deposition and thermal equilibration. Numerical tests verify that the upgraded PM1D code accurately simulates collisional effects across a broad range of laser-plasma parameters while maintaining robust numerical stability and high computational efficiency. Our simulations further reveal that collisional damping can effectively suppress stimulated Brillouin scattering, while its direct impact on stimulated Raman scattering (SRS) is negligible. Notably, collisional effects not only contribute directly to collisional absorption but can also enhance the anomalous absorption driven by various LPI processes. Moreover, the increase in plasma temperature resulting from collisional absorption elevates the electron plasma wave frequency, which may manifest as an experimentally observable redshift of the SRS scattered light. This work therefore establishes a robust numerical framework for investigating the complex interplay between collisional processes and LPIs in laser-target coupling.