Exploration of microscopic physical processes of Z-pinch by a modified electrostatic direct implicit particle-in-cell algorithm  

作　　者：Kaixuan Li Cheng Ning Ye Dong Chuang Xue 李开轩;宁成;董烨;薛创(Institute of Applied Physics and Computational Mathematics,Beijing 100088,China)

机构地区：[1]Institute of Applied Physics and Computational Mathematics,Beijing 100088,China

出　　处：《Chinese Physics B》2024年第9期433-442,共10页中国物理B（英文版）

基　　金：the graduated students Zhixing Feng,Xiaoqiang Zhang,and Deli Fang for their excellent works to develop the PIC simulation codes of Z-pinch.This research was partly supported by the National Natural Science Foundation of China(Grant Nos.11675025 and 11135007);the Innovation Project of China Academy of Engineering Physics(Grant No.CX2019030).

摘　　要：For investigating efficiently the stagnation kinetic-process of Z-pinch,we develop a novel modified electrostatic implicit particle-in-cell algorithm in radial one-dimension for Z-pinch simulation in which a small-angle cumulative binary collision algorithm is used.In our algorithm,the electric field in z-direction is solved by a parallel electrode-plate model,the azimuthal magnetic field is obtained by Ampere’s law,and the term for charged particle gyromotion is approximated by the cross product of the averaged velocity and magnetic field.In simulation results of 2 MA deuterium plasma shell Zpinch,the mass-center implosion trajectory agrees generally with that obtained by one-dimensional MHD simulation,and the plasma current also closely aligns with the external current.The phase space diagrams and radial-velocity probability distributions of ions and electrons are obtained.The main kinetic characteristic of electron motion is thermal equilibrium and oscillation,which should be oscillated around the ions,while that of ion motion is implosion inwards.In the region of stagnation radius,the radial-velocity probability distribution of ions transits from the non-equilibrium to equilibrium state with the current increasing,while of electrons is basically the equilibrium state.When the initial ion density and current peak are not high enough,the ions may not reach their thermal equilibrium state through collisions even in its stagnation phase.

关 键 词：Z-PINCH PARTICLE-IN-CELL ion heating charged particle collisions 

分 类 号：O53[理学—等离子体物理]