The mechanism of energy release and field-aligned current generation during substorms and solar flares

In this paper, the mechanisms of field-aligned current (FAC) and westward electrojet generation are considered on the base of space measurements and laboratory simulation. Upward and downward FAC are generated in the Earth magnetotail current sheet (CS) due to the tail earthward electric field. They are connected in the ionosphere by the Pedersen current. The FAC enhancement takes place during magnetic reconnection and explosive energy release at a substorm. Electron acceleration in upward FAC produces fast electron precipitation and aurora appearance. The westward electrojet (Hall current) is located between two opposite directed sheets of FAC. The current in the jet is determined by the Hall conductivity in the ionosphere. The similar current systems in the solar corona are responsible for energy transfer to the chromosphere during a solar flare. The solar flare model is built on the base of observations and 3D MHD numerical simulation for compressible resistive plasma