中国物理B ›› 2018, Vol. 27 ›› Issue (2): 25207-025207.doi: 10.1088/1674-1056/27/2/025207

• PHYSICS OF GASES, PLASMAS, AND ELECTRIC DISCHARGES • 上一篇    下一篇

Analytical studies on the evolution processes of rarefied deuterium plasma shell Z-pinch by PIC and MHD simulations

Cheng Ning(宁成), Xiao-Qiang Zhang(张小强), Yang Zhang(张扬), Shun-Kai Sun(孙顺凯), Chuang Xue(薛创), Zhi-Xing Feng(丰志兴), Bai-Wen Li(李百文)   

  1. Institute of Applied Physics and Computational Mathematics, Beijing 100088, China
  • 收稿日期:2017-07-25 修回日期:2017-09-16 出版日期:2018-02-05 发布日期:2018-02-05
  • 通讯作者: Cheng Ning E-mail:ning_cheng@iapcm.ac.cn
  • 基金资助:
    Projected supported by the National Natural Science Foundation of China (Grant Nos. 11675025, 11135007, and 11405012).

Analytical studies on the evolution processes of rarefied deuterium plasma shell Z-pinch by PIC and MHD simulations

Cheng Ning(宁成), Xiao-Qiang Zhang(张小强), Yang Zhang(张扬), Shun-Kai Sun(孙顺凯), Chuang Xue(薛创), Zhi-Xing Feng(丰志兴), Bai-Wen Li(李百文)   

  1. Institute of Applied Physics and Computational Mathematics, Beijing 100088, China
  • Received:2017-07-25 Revised:2017-09-16 Online:2018-02-05 Published:2018-02-05
  • Contact: Cheng Ning E-mail:ning_cheng@iapcm.ac.cn
  • About author:52.58.Lq; 52.65.-y; 52.59.Qy
  • Supported by:
    Projected supported by the National Natural Science Foundation of China (Grant Nos. 11675025, 11135007, and 11405012).

摘要: In this paper, we analytically explore the magnetic field and mass density evolutions obtained in particle-in-cell (PIC) and magnetohydrodynamics (MHD) simulations of a rarefied deuterium shell Z-pinch and compare those results, and also we study the effects of artificially increased Spitzer resistivity on the magnetic field evolution and Z-pinch dynamic process in the MHD simulation. There are significant differences between the profiles of mass density in the PIC and MHD simulations before 45 ns of the Z-pinch in this study. However, after the shock formation in the PIC simulation, the mass density profile is similar to that in the MHD simulation in the case of using multiplier 2 to modify the Spitzer resistivity. Compared with the magnetic field profiles of the PIC simulation of the shell, the magnetic field diffusion has still not been sufficiently revealed in the MHD simulation even though their convergence ratios become the same by using larger multipliers in the resistivity. The MHD simulation results suggest that the magnetic field diffusion is greatly enhanced by increasing the Spitzer resistivity used, which, however, causes the implosion characteristic to change from shock compression to weak shock, even shockless evolution, and expedites the expansion of the shell. Too large a multiplier is not suggested to be used to modify the resistivity in some Z-pinch applications, such as the Z-pinch driven inertial confinement fusion (ICF) in a dynamic hohlraum. Two-fluid or Hall MHD model, even the PIC/fluid hybrid simulation would be considered as a suitable physical model when there exist the plasma regions with very low density in the simulated domain.

关键词: shell Z-pinch, PIC and MHD simulations, wire-array Z-pinch

Abstract: In this paper, we analytically explore the magnetic field and mass density evolutions obtained in particle-in-cell (PIC) and magnetohydrodynamics (MHD) simulations of a rarefied deuterium shell Z-pinch and compare those results, and also we study the effects of artificially increased Spitzer resistivity on the magnetic field evolution and Z-pinch dynamic process in the MHD simulation. There are significant differences between the profiles of mass density in the PIC and MHD simulations before 45 ns of the Z-pinch in this study. However, after the shock formation in the PIC simulation, the mass density profile is similar to that in the MHD simulation in the case of using multiplier 2 to modify the Spitzer resistivity. Compared with the magnetic field profiles of the PIC simulation of the shell, the magnetic field diffusion has still not been sufficiently revealed in the MHD simulation even though their convergence ratios become the same by using larger multipliers in the resistivity. The MHD simulation results suggest that the magnetic field diffusion is greatly enhanced by increasing the Spitzer resistivity used, which, however, causes the implosion characteristic to change from shock compression to weak shock, even shockless evolution, and expedites the expansion of the shell. Too large a multiplier is not suggested to be used to modify the resistivity in some Z-pinch applications, such as the Z-pinch driven inertial confinement fusion (ICF) in a dynamic hohlraum. Two-fluid or Hall MHD model, even the PIC/fluid hybrid simulation would be considered as a suitable physical model when there exist the plasma regions with very low density in the simulated domain.

Key words: shell Z-pinch, PIC and MHD simulations, wire-array Z-pinch

中图分类号:  (Z-pinches, plasma focus, and other pinch devices)

  • 52.58.Lq
52.65.-y (Plasma simulation) 52.59.Qy (Wire array Z-pinches)