针对相对论快电子束在高密度压缩芯区等离子体中的能量沉积过程开展物理建模、程序研制和数值模拟研究。从等离子体粒子碰撞的基本物理出发, 综合考虑了高能电子与背景等离子体之间的短程两体碰撞过程和长程集体效应, 建立了相对论Fokker-Planck动理学模型, 通过采用球谐展开的方法, 推导得到了适于数值求解的方程形式并根据方程特点开展相应的数值算法研究及程序研制并完成了物理考核, 对快点火能量沉积的典型物理算例进行了模拟研究, 并针对即将在神光Ⅱ升级装置上开展的快点火物理实验进行了初步的物理分析。

Energy deposition of ultra-intense laser driven fast electrons into the highly compressed fuel core plasmas is of great importance in assessing the overall coupling efficiency in fast ignition scheme. In this paper, a relativistic kinetic model is established based on fundamental principles of plasma collisions to explore the energy deposition process. The relativistic Fokker-Planck equation is derived, including both the binary collision and the contribution from plasma collective response. It is formulated in a differential form with the help of analogous Rosenbluth potentials. Its explicit expression in three-dimensional momentum space is obtained via spherical harmonics expansion method, in which only simple differentiations and integrations are involved. Corresponding numerical algorithms are developed as well as the kinetic code. Typical fast ignition physical cases are presented, and it is used to make a preliminary analysis for the coming FI experiments in Shengguang Ⅱ laser facility.