K-H不稳定性在多电流片系统磁场重联中的效应

等离子体系统中存在两个或多个电流片时，电流片中发生的不稳定性可能会相互作用．行星际磁场北向时，背阳面碰层顶电流片与磁尾等离子体片之间可能发生相互作用，高纬边界层强烈的流场剪切可能促进磁场重联，产生磁层亚暴．本文运用二维可压缩磁流体模拟研究具有强流场剪切的多个电流片系统中磁场重联的演化．结果表明，Kelvin－Helmholtz不稳定性使多电流片系统的磁场重联过程明显加快；相邻电流片之间的距离越近，两者相互作用越强，重联增长率越大；在三电流片系统中，超Alfven速度强流场导致外侧两个电流片中出现强烈的磁场重联，并引发中心电流片的磁场重联．行星际磁场北向时，也可能发生磁层亚暴．

A SIMULATION STUDY OF MAGNETIC RECONNECTION IN A MULTIPLE CURRENT SHEET SYSTEM

It is found that when the interaction between two current sheets causes reconnection, the region which separates two sheets dissipates its magnetic energy quickly and becomes thin. MHD Kelvin-Helmholtz instability is responsible for the development of magnetic reconnection at multiple current sheet system. The closer the distance between neighbour current sheets is,the stronger the interaction is. In tri-current sheet system, the magnetic reconnection in two side current sheets caused by super Alfven velocity fluid can induce magnetic reconnection in the middle current sheet We also suggested that if there is magnetic reconnection at high latitude boundary layer while IMF is northward, the reconnection must influence the plasma sheet in magnetotail, and induce magnetic reconnection in it.