Dynamic Process in the Magnetic Reconnection of Magnetopause

The effects of electron pressure gradient term in the generalized Ohm's law are studied by a three-D MHD simulation code under condition of high plasma Beta and small ion inertial length. The results show that the electron pressure gradient term increases the velocity of electrons and ions, thus increases the field aligned current, and finally leads to the increase of core magnetic filed. Since the field-aligned current is the principal way by which the magnetosphere is coupled with the ionosphere, the electron pressure gradient term enhances the coupling of magnetosphere-ionosphere. The electron pressure gradient can also generate the dynamic Alfven waves. It is supposed that this Alfven waves change the velocity of particles.