驱动重联过程中等离子体团的聚合

本文对驱动重联过程作了二维可压缩磁流体动力学模拟．对于长的计算域（１：４），在持续入流的作用下形成了双重磁岛结构，这些磁岛在向外运动的过程中不断靠近，逐渐聚合成为一个大的等离子体团，并继续向外运动．这说明在地球磁层顶和磁尾所观测到的大尺度磁结构，很可能是在驱动重联过程中，由较小的等离子体团聚合后形成的．并初步揭示了在空间等离子体中，磁岛的聚合过程难以直接观测的动力学原因．

PLASMOID COALESCENCE IN DRIVEN RECONNECTION PROCESSES

The driven reconnection process is studied by a two-dimensional compressible magnetohydrodynamic code.A magnetic field structure with two magnetic islands is formed by a sustained inflow imposed at the boundary in a long simulation box.The two magnetic islands gradually come close to each other and finally coalesce into a large one as they are convected outward, and then the large plasmoid goes on moving up. It is proved that the large-scale magnetic structures in the magnetopause and magnetotail should result form the coalescence of small-scale magnetic structures in driven reconnection processes. Moreover, we present preliminarily the dynamic reason why it is difficult to directly observe the coalescence process in space plasma.