Magnetic reconnection in the magnetodisk of centrifugally dominated giant planets

Abstract

Magnetic reconnection is crucial in understanding magnetospheric dynamics and aurorae processes at planets. In planetary magnetospheres, magnetic reconnection has often been identified on the dayside magnetopause and in the nightside magnetodisk, where thin-current-sheet conditions are conducive to reconnection. At the Earth, the magnetopause and magnetotail current sheets are primarily controlled by the upstream solar wind. At Jupiter and Saturn, their fast rotation and internal mass sources lead to an additional current sheet that encircles the planet, forming a magnetodisk inside the magnetosphere. The reconnection processes in the magnetodisk current sheet are associated with centrifugal force-driven dynamics. The magnetodisk reconnection is not limited to the nightside but is discretely distributed at all local times inside the magnetosphere. The reconnection sites also rotate with the magnetosphere. These widely distributed small-scale reconnection sites can result in the global release of energy and mass from the magnetosphere.