Study On The Size And Shape Of Magnetopause In The Meridian Plane And The Energy Transfer Through Magnetopause

The characteristics of the location and shape of the magnetopause in the noon-midnight meridian plane and its variations with interplanetary conditions are difficulties in space weather studies. Using the global magneto-hydrodynamics (MHD) simulations of the solar wind-magnetosphere-ionosphere system and combined with the current density criterion, the location and shape of the magnetopause in the noon-midnight meridian plane is studied in this paper. The maximum of the current density in different radial direction may appear in different areas in magnetosphere for the varying interplanetary conditions. To determine the magnetopause, the empirical model of Boardsen2000is used as reference for the selection of the appropriate maximum points in different radial direction.The simulation results show that the magnetopause shape has a concave structure, which is different from equatorial plane in the noon-midnight meridian plane.When southern IMF Bz (BZ<0) grows small until north IMF Bz (Bz>0) gradually increasing in the low solar wind speed process, the subsolar position r0keeps gradually increasing, and polar cusp height also increases, the tail angle reduces gradually. In the IMF which are certain cases, the magnetopause is integrally compressed, moreover, the configuration essentially unchanged in the high speed solar wind, that is to say the change of dynamic pressure does not destroy the self-similarity of the magnetopause.Furthermore, the stream lines method is also employed to determine the meridian plane position, we get a much smoother3dimensional surface which is smoother than the curve line obtained through the maximum current density method. On the base of the3dimensional magnetopause, we calculated the energy transfer through the magnetopause using our MHD simulation data. The results show that the input energy mainly depends on the Poynting energy and thermal energy, and the output energy mainly depends on the Poynting energy. In addition, higher solar wind speed and southern IMF are more conductive for energy to transfer into the inner-magnetosphere. We analysis the energy transfer characteristics of the whole sector and find that the total energy and the Poynting energy have good correlations at all the sectors and the input energy is on the rise generally, despite the difference of interplanetary conditions.