| The plasmasphere is the core areawhere the Earth’s inner magnetosphere interacts. Thesignificant changes of structure in the plasmasphere and the dynamic process strongly affect thestructure of the inner magnetosphere and the near-earth space environment during geomagneticdisturbances, whichcan seriously interfere the space-based technology systems. A bettercomprehension of the plasmasphere structure during the geomagnetic disturbance lays an importantbasis of understanding the coupling of inner magnetospherein depth. The detection results of IMAGEsatellites reveal a variety of fine structures of the plasmasphere during the magnetic disturbance, suchas plume, shoulder, channel, groove, et al. It is important to understand and explain the mechanism ofthe formation in plasmasphere. In this study, based on the single particle orbit theory, the evolution ofequatorial plasmasphere is simulated by using “test particles†method, Tsyganenko’s magnetic modeland Weimer’s electric model during geomagnetic disturbance. And the main results are as follows:Adopting the Tsyganenko’s model and Weimer model of magnetic field with the same inputparameters, asemi-empirical magnetospheric electric field model will be obtained after mapping theionospheric Weimer’s electric field along with the magnetic lines to magnetosphere. Thecharacteristicsofprojection electric fieldsare analyzed and compared under T96, T01and T04. Theirresponse to IMF and the solar wind parameters are also investigated. The results show that projectionelectric field of T04responds more obviously to Dst index. And, the formation and intensity aremainly affected by the IMF and tilt angle parameters.Based on particle dynamics theory and test particle method, the evolution process ofplasmasphere during the magnetic disturbance is simulated respectively by T96and T04models.Thesimulation is compared with EUV/IMAGE image. The result shows: T04is more accurate; the plumeis produced when convection increases, at which some particles from the original plasmapause arepeeled off and sucked into the magnetosphere;theshoulder is produced when the IMF changes fromsouth to north; it firstly appears at the dawn, then rotates counterclockwise with the Earth and reachesthe afternoonforming the second plume; the channel is the density cavity that is produced whenplumes wrap around the main plasmasphere. |
