Magnetosphere response to stationary solar wind forcing at various plasma resistivities in 2D MHD simulation

Abstract

The magnetosphere response to the stationary solar wind forcing at various values of the plasma resistivity is studied. The simulation is performed within two-dimensional (2D) MHD resistive model; the meridional plane is considered. The solar wind and southward interplanetary magnetic field (IMF) are supposed to be stationary. The calculations were carried out for two plasma resistivity values ηp = {106; 104} Ω·m, assumed constant in the whole flow field. At higher plasma resistivity the steady magnetosphere convection (SMC) takes place; the solution is symmetric relative to the x-axis. At lower resistivity the sawtooth event is realized; the solution is quasi-periodic and asymmetric. The asymmetry is connected with the formation of the vortex street of Karman type. The sequence of phases of the sawtooth cycle, as well as the evolution of magnetic lines of force and the flow structure in each phase is analyzed. In both solutions the day side magnetic reconnection occurs through the two x-points disposed symmetrically at the top and bottom peaks of the magnetic island.