Line Numerical Simulation Of Interplanetary Disturbances, And The Interaction Of The Current Sheet

The helmet streamer in the corona or the interplanetary current sheet is aspecial structure in the interplanetary space. The CME eruption is close relativeto the helmet streamer in the corona. And the propagating of the interplanetaryshock brought about by CME is also affected badly by the interplanetary currentsheet. Magnetic reconnection is an important physical process which happensinside the current sheet, and it is the important path by which the magneticenergy is conversed or released. In this paper, the study about the interactionbetween the solar wind disturbance and the current sheet is mainly carried out intwo aspects: First, the characteristic propagating of this kind of CMEs erupting inthe open magnetic field between two helmet streamers has been studied by theMHD numerical simulation. Second, the Hall effect during magneticreconnection has been studied respectively through numerical simulating andtheoretically analyzing. And some of its characteristics have been discussed inthe aspect of the interaction between the disturbance and the sheet current. On one hand,in this paper, the CME erupting in the open magnetic fieldbetween two helmet streamers are simulated numerically, and the interactionbetween the disturbance and the current sheet has been studied. The spacecraftSMM had observed the characteristic propagating of the CME erupting in theopen magnetic field between two helmet streamers, as well as the distortion andthe deflection of the corresponding helmet streamers during the solar-peak years.In this paper, by using the 2.5-dimension MHD equations, the complicatedinteraction between CME and helmet streamer has been studied throughnumerical simulating. In the numerical simulation results, not only that observedby the spacecraft has been showed out, but also, a new phenomenon has beenfound: under the interaction between the CME and the helmet streamer, the axialcomponent of the magnetic-field vector inside the helmet streamer can beinversed. On the other hand, the Hall effect in the process of magnetic reconnection isstudied respectively through numerical simulating and theoretically analyzing.During magnetic reconnection, the Hall effect plays the important role in thedecoupling of electrons and ions of plasma. In this paper, the two-dimensionincompressible MHD equations have been corrected, and the Hall term in theinduction equation has been taken into consideration. And then, by using theseequations, the Hall effect has been simulated numerically, and the structure of theHall effect and its change characters under the interaction between thedisturbance and the current sheet have been studied. The numerical simulationresults about the structure of the Hall electric field accord well with that obtainedby theoretically analyzing. The decoupling of electrons and ions of plasma can beshown out clearly in this structure of the Hall electric field. Based on thenumerical simulation result and the theoretical analysis result, a new conclusionhas been reached: During magnetic reconnection, energetic electrons can beaccumulated in the vicinity of the magnetic reconnection point due to the Halleffect. This conclusion can be supported by both the observation result obtainedby spacecraft Geotail and the result obtained in the Tokamak experiment.