超热电子在稠密等离子体中输运的混合粒子模拟方法  

Hybrid Particle-in-Cell/Fluid Model for Hot Electron Transport in Dense Plasmas

作　　者：徐涵[1] 卓红斌[2] 杨晓虎[2] 侯永[2] 银燕[2] 刘杰[1] 

机构地区：[1]国防科技大学计算机学院,长沙410073 [2]国防科技大学理学院,长沙410073

出　　处：《计算物理》2017年第5期505-525,共21页Chinese Journal of Computational Physics

基　　金：国家自然科学基金(11275269;11665012;11475259;11305264);科学挑战计划(JCKY2016212A505);中科院上海光机所强场激光物理国家重点实验室开放课题资助项目

摘　　要：相对论激光等离子体相互作用以及所产生的带电粒子束在高密度等离子体中的输运行为非常重要.该物理问题的数值模拟研究仍面临技术挑战.本文介绍一种粒子/流体混合模拟方法.该方法中超热电子采用动力学方法描述,背景冷的稠密等离子体采用简化的流体方程描述,适合于超热电子密度远小于背景电子密度,超热电子能量远大于背景电子温度.我们的三维并行混合模拟程序HEETS的模拟结果表明:背景材料的电离和电阻率模型至关重要,将严重影响高能电子输运过程的模拟.One of key issues in high energy density physics is clarification of transport and energy deposition of laser-produced fast electrons traveled through dense plasma.However,modeling these systems numerically is still a great challenge.In this paper,we introduce a PIC/fluid hybrid model.In this hybrid method,fast electrons are modeled by a relativistic Fokker-Planck equation,which numerically solved by reducing it to equivalent stochastic differential equations.Background electrons and ions are treated as two-fluid model.Collisions,electric and magnetic fields,and evolutions of resistivity due to heating of background are included.Treatment is valid for fast electron number densities much less than that of background,fast electron energies much greater than background temperature,and time scales short enough that magnetic diffusion and thermal conduction can be negligible.Model of ionization and resistivity also determine validity of the model.

关 键 词：高能量密度物理 超热电子输运 混合粒子模拟 

分 类 号：O53[理学—等离子体物理]