非稳态多重X线重联的类型与特征

为了进一步认识间歇性多重Ｘ线重联的特征，本文分析计算结果，发现入流自边界进入后向两侧发散，沿着ｘ轴（ｚ＝０）和出流边界（ｚ＝２），压强Ｐ和磁场Ｂ的分布形态表明这种非稳态重联属快模式扩张型．数值结果还表明，进入扩散区的入流马赫数Ｍ_ｉ与磁雷诺数Ｒｍ之间基本满足关系式Ｍ_ｉ≈１．５Ｒ_ｍ^－１／２─１．７５Ｒ_ｍ^－１／２，而且等离子体的加速与压强Ｐ_ｔ(Ｐ_ｔ

THE CHARACTERISTICS AND TYPE OF THE UNSTEADY STATE MAGNETIC RECONNECTION

The intermittent multiple X-line reconnection is numerically analyzed in this paper. A fast-mode expansion is expected in the light of the divergent plasma flow and the features of the profiles for magnetic field strength B and pressure P along the lines z=0 and z=2. It can be seen from numerical results that the inflow Mach Number Mi reached at the diffusion region scales with magnetic Reynolds number Rm as Rm-1/2 and the plasma is accelerated by the pressure gradient force. These characteristics are close to the features of Sweet-Parker reconnection with a long current sheet. The tangential velocity component Vz at the inflow boundary (x=1).is defined as V 0. The comparison of numerical results shows that a low uniform resistivity (corresponding to high Magnetic Reynolds nuinber) play a key role in the formation of the unsteady multiple X-line reconnection, but the different setting of tangential velocity Vz at x =1 is not so important.