ISSDE: A Monte Carlo implicit simulation code based on Stratonovich SDE approach of Coulomb collision
ISSDE: A Monte Carlo implicit simulation code based on Stratonovich SDE approach of Coulomb collision
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ISSDE：基于库仑碰撞 Stratonovich SDE 方法的蒙特卡洛隐式仿真代码
DOI：
10.1088/1674-1056/abefc7
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发表时间：
2021
影响因子：
1.7
通讯作者：
Zhuang Ge
中科院分区：
文献类型：
--
作者：
Zheng Yifeng;Xiao Jianyuan;Wang Yanpeng;Zheng Jiangshan;Zhuang Ge
开发了一个求解库仑碰撞等离子体随机微分方程的蒙特卡罗隐式模拟程序--隐式Stratonovich随机微分方程（ISDEs）。该程序的基本思想是Fokker-Planck方程和Stratonovich随机微分方程之间的随机等价性。采用分裂方法提高了库仑碰撞带电粒子动力学算法的数值稳定性。考虑了洛伦兹等离子体、麦克斯韦等离子体和背景等离子体的任意分布函数的情况。隐式中点法的采用保证了扩散项的能量守恒，从而提高了数值稳定性。ISO9000是用C++构建的，具有标准接口和可扩展模块。用该方法研究了电子束在非磁化等离子体中的慢化过程和在磁化等离子体中的弛豫过程，证明了该方法的正确性和可靠性。
A Monte Carlo implicit simulation program, Implicit Stratonovich Stochastic Differential Equations (ISSDE), is developed for solving stochastic differential equations (SDEs) that describe plasmas with Coulomb collision. The basic idea of the program is the stochastic equivalence between the Fokker–Planck equation and the Stratonovich SDEs. The splitting method is used to increase the numerical stability of the algorithm for dynamics of charged particles with Coulomb collision. The cases of Lorentzian plasma, Maxwellian plasma and arbitrary distribution function of background plasma have been considered. The adoption of the implicit midpoint method guarantees exactly the energy conservation for the diffusion term and thus improves the numerical stability compared with conventional Runge–Kutta methods. ISSDE is built with C++ and has standard interfaces and extensible modules. The slowing down processes of electron beams in unmagnetized plasma and relaxation process in magnetized plasma are studied using the ISSDE, which shows its correctness and reliability.