非对称四极无力场的磁能释放

MAGNETIC ENERGY RELEASE OF ASYMMETRICAL QUADRUPOLAR FORCE-FREE FIELDS

本文采用二维三分量耗散ＭＨＤ模型，对带高电流层的局地非对称的四极无力场的磁能释放过程进行数值模拟，结果表明，磁能释放过程大体可以分为两个阶段：高电流层引起的异常电阻耗散使该层等离子体加热至３×１０６Ｋ的高温，形成一高温环；在高电流层耗散的触发下，磁分隔面的电流急剧增长并爆发异常电阻耗散和磁场重联，导致耀斑发生，主要的能量释放发生在磁分隔线和高剪切无力场中的磁分隔面上，等离子体温度可以达到１．９×１０７Ｋ。上述无力场的触发释能过程可能是太阳耀斑的一种重要的释能机制。

Using a two-dimensional dissipative MHD model,a numerical simulation is presented concerning the energy release of an asymmetrical quadrupolar force free field.The energy release process is largely divided into two phases: anomalous resistive dissipation in the high current layer heats the plasma there to 3×106K,forming a high temperature loop;the dissipation of the high current layer triggers a growth of electric current on the separatrix and thus anomalous resistive dissipation and magnetic reconnection take place there,leading to a solar flare.Main site for the magnetic energy release is located at the separator and the separatrix in highly sheared force free field, and the plasnia temperature may reach 1.9×107K.This triggered energy release process is probably an important mechanism for energy release associated with solar flares.