向阳面磁顶区可压缩涡旋诱发重联模拟研究:通量传输事件的形成和结构

本文用二维可压缩MHD模型,模拟研究了向阳面磁顶区的涡旋诱发重联过程。重联过程的结果形成了同心的磁流体涡旋。同时还对可压缩模型与不可压缩模型的异同点作了对比研究。结果表明,在同样条件下,可压缩情况的涡旋发展的增长率比不可压缩情况慢;结构特性无显著变化。本文指出,涡旋诱发重联是产生通量传输事件的一种重要机制。通量传输管可看作为磁流体涡旋管。对通量传输事件诸物理量(磁场、速度、密度、压力和温度)的分布特性作了模拟研究,可解释FTEs的主要观测特性。 

SIMULATION OF COMPRESSIBLE VORTEX-INDUCED RECO-NNECTION AT THE DAYSIDE MAGNETOPAUSE REGION:THE FORMATION AND STRUCTURE OF FTES

By using a two-dimensional compressible MHD model, the local reconnection processes at the dayside magnetopause region are simulated based on the theory of vortex-induced reconnection. This process is: first, a fluid vortex is formed, which in turn, induce the reconnection so that a magnetic vortex is formed, and finally there will be a magnetic fluid vortex (MF vortex), of which the three-dimensional structure is a MF vortex tube. The MF vortex tube connectes the magnetosheath and the magnetosphere region. The compressible model is compared with the incompressible model, it is found that the growth of vortices under incompressible condition is faster than that for compressible condition, but the forms of vortices are analogous. It is thought that vortes-induced reconnection is an important machanism of flux transfer events (FTEs) formation, and the FTE tube is a MF vortex tube. The signatures of the magnetic field, velocity, density, temperature, and pressure of the FTE are simulated. The simulation results are consistent with observational examples of FTES.