计算物理 ›› 2017, Vol. 34 ›› Issue (5): 555-562.

• 专题:超强激光等离子体相互作用的数值模拟 • 上一篇    下一篇

电子束能量沉积的相对论Fokker-Planck方程的计算方法

张华1,2, 吴思忠1, 周沧涛1,2, 何民卿1, 蔡洪波1,2, 曹莉华1,2, 朱少平1, 贺贤土1,2   

  1. 1. 北京应用物理与计算数学研究所, 北京 100094;
    2. 北京大学应用物理与技术中心, 北京 100871
  • 收稿日期:2017-03-30 出版日期:2017-09-25 发布日期:2017-09-25
  • 作者简介:张华(1977-),男,博士,副研究员,从事激光等离子体数值模拟研究,E-mail:zhang_hua@iapcm.ac.cn
  • 基金资助:
    大科学装置国家重点研发计划(2016YFA0401100)及国家自然科学基金(91230205,11575031)资助项目

Numerical Method of Relativistic Fokker-Planck Equation for Energy Deposition of Fast Electrons

ZHANG Hua1,2, WU Sizhong1, ZHOU Cangtao1,2, HE Minqing1, CAI Hongbo1,2, CAO Lihua1,2, ZHU Shaoping1, HE Xiantu1,2   

  1. 1. Institute of Applied Physics and Computational Mathematics, Beijing 100094, China;
    2. Center of Applied Physical Technology, Peking University, Beijing 100871, China
  • Received:2017-03-30 Online:2017-09-25 Published:2017-09-25

摘要: 针对相对论电子束在高密度等离子体中的能量沉积过程,建立三维动量空间中快电子能量沉积的相对论Fokker-Planck方程的可计算物理模型,构造数值算法并研制数值模拟程序.通过与解析模型和蒙特卡罗模拟相比较,验证数值方法和程序的可靠性.在二维动量空间的模拟基础上,通过计算能量区间为0.5 MeV~3.5 MeV的快电子在背景密度为300 g·cm-3的氘氚等离子体中的能量沉积过程,发现由于碰撞效应使平均散射角趋近平衡,三维动量空间计算快电子连续射程和穿透深度与二维结果基本一致.

关键词: 电子束, 能量沉积, 相对论Fokker-Planck方程

Abstract: For energy deposition of fast electrons in high density plasma, a relativistic Fokker-Planck equation in three-dimensional momentum space is introduced. It includes both binary collision and contribution from plasma collective response. Numerical method as well as kinetic code of the equation is developed. Typical energy deposition cases are presented with comparison with stopping power model. Energy deposition of fast electrons with energy from 0.5 MeV to 3.5 MeV in 300 g·cm-3 DT plasma are simulated. It shows that scattering angle ϕ plays minor role on range and penetration depth of energy deposition of fast electrons.

Key words: electron beam, energy deposition, relativistic Fokker-Planck equation

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