2004-03-18 23:10～23:50 ur期间，“双星（Double Star）”探测一号卫星（TC-1）在向阳面磁层顶高纬晨侧由内向外穿越磁层顶，其时TC-1的GSM坐标为（7.5RE，-5.5RE，-5.4Re），RE为地球半径。穿越过程中TC-1观测到了8个通量管和1个磁通量传输事件（FTEs）。在此期间Cluster星簇位于向阳面太阳风内，其GSM坐标为（18.0RE，-3.1RE，-6.2RE），其4颗卫星监测到行星际磁场（IMF）的Bz分量持续南向，BY有较大的负值．本文的研究表明：TC-1观测到的前7个通量管具有准周期重现性，周期大约是1～4min，明显小于以前所观测到的FrEs的平均周期（8～11min）；所有的通量管都具有较强的核心场．本文分别使用最小方差分析法（MVA）和Grad-Shafranov反演方法（GSR）对通量管的轴向进行了分析和对比，发现所有的通量管主轴基本沿晨昏向，结果显示GSR方法在轴向分析上比MVA优越。本文使用GSR方法对通量管的磁场结构进行了分析，恢复出了通量管的磁场在卫星穿越面的结构图；此外，本文还对这次多重通量管事件进行了deHoffmann-Teller（HT）分析，结果表明，所有通量管大致朝南极方向运动，均来源于向日面低纬区域．这说明它们可能起源于向日面低纬区，由该区的磁场分量重联产生。

We show in this paper that intermediate shocks are formed from ki-netic Alfven waves through wave form continuous steepening. From the action of nonlinear interaction and dispersion Alfven solitons are formed and then evolve into shocks. We calculated the traveling stationary struc-tures directly from nonlinear autonomous equations which we had derived. These traveling stationary structures correspond to intermediate shock, switch-on shock or Alfven solitary waves. Another kind of rare discontinuity was discovered in the calculation from the rarefying solitary waves. The solitary wave series remain on the front of the shocks because of no strong dissipation appears in the equation. When we added some anomalous dissipation terms to the equations, intermediate shocks with increased in entropy appeared.

We present the temporal evolution of magnetic field topology in the magnetotail with a southward IMF in order to identify the magnetic reconnection. The magnetic field topology is uniquely determined by the eigenvalues of the critical points, if they are not degenerated. This is because the critical points, their number, and the rules between them characterize the whole magnetic field pattern. At the critical points, the magnetics become zero. The magnetic vector field curves and surfaces are both integrated out along the principal directions of certain classes of critical points including the Earth’s dipole magnetic field. The skeleton that includes the critical points, characteristic curves, and surfaces provides the three-dimensional topological structure of the reconnection. The change of the skeleton, i.e. the change of the topology, has revealed the occurrence of magnetic reconnection. Namely, threedimensional "X-points" or the more-than-two critical points that are saddle and connected each other are unstable and can move, vanish, and generated.

Magnetic reconnection at the high-latitude magnetopause is studied using 2.5-dimensional Hall-MHD simulation. Concentric flow vortices and magnetic islands appear when both Hall effect and sheared flow are considered. Plasma mixing across the magnetopause occurs in the presence of the flow vortices. Reconnected structure generated in the vicinity of the subsolar point changes its geometry with increasing flow shear while moving to high latitudes. In the presence of flow shear, with the Hall-MHD reconnection a higher reconnection rate than with the traditional MHD is obtained. The out-of-plane components of flow and magnetic field produced by the Hall current are redistributed under the action of the flow shear, which makes the plasma transport across the boundaries more complicated. The simulation results provide some help in understanding the dynamic processes at the high latitude magnetopause.