能量输运对柱状等离子体开关磁场穿透过程的影响

Influence of energy transport on magnetic field penetration in high-density coaxial plasma opening switch

对于高密度、导通时间为μs级的柱状等离子体开关,利用磁流体动力学理论(MHD),对其导通阶段的磁场穿透过程进行了模拟,得到了磁场分布随时间的变化;研究了开关导通过程中能量输运导致的温度不均匀分布对磁场穿透过程的影响。模拟结果表明:对于高密度等离子体开关,磁场以远大于磁扩散速率的速度穿透到等离子体中;在磁压对等离子体产生的压缩效应和欧姆加热效应共同作用下,激波区域的等离子体温度显著升高,这进一步加速了磁场穿透;当考虑能量输运方程时,开关导通时间为0.87μs,比等温模型的结果0.92μs短,与实验结果0.87μs相一致。

Based on the two-dimensional magnetohydrodynamic（MHD） theory, the magnetic field penetration process at the conduction stage of a high-density, coaxial plasma opening switch （POS） was numerically simulated, and the evolution of the magnetic field distribution with time was obtained. The influence of the energy transportation on the magnetic field penetration was studied, It is shown that the magnetic field penetrates into the plasmas rapidly, and the temperature in the shock region increases greatly. The non-uniform distribution of temperature resulted from the compression of the plasma and the Ohmic heating speeds up the magnetic field penetration significantly, The conduction-time of the POS is 0.87 μs by the model with the energy transportation, which is shorter than that of the isothermal model and it agrees well with the experimental result.