Plasma Resources of Jupiter＇s Main Auroral Oval

Jupiter＇s aurora exhibits three distinct regions： the satellite footprint emissions, the main oval emissions and all polar emissions. As the case of the Earth, the auroral morphology contains both qualitative and quantitative clues about magnetospheric structure and dynamics. We map along the magnetic field lines to the equatorial plane to track the plasma resources of the main oval in an equilibrium model of Jupiter＇s magnetosphere. The footprints of the satellites are good references to help us to check the mapping. We find out that the plasma of oval emissions originates from the equatorial plane with a distance of～22.0RJ, which is closer to the Jupiter than 30RJ given by the VIP4 model. However the difference does not deny the conclusion that the upward Birkeland currents produce the oval emissions.