DYNAMICS OF AURORAL ELECTROJETS AND ENERGETICS OF SUBSTORMS

The dynamics of westward auroral electrojets in the course of magnetos pheric substorms is studied according to the data of a meridional chai n of magnetometers. It is shown that, during active phases of the subs torm, the westward electrojet becomes inhomogeneous and some current f ilaments appear in it; some of them drift polewards, some other shift equatorwards. A method is proposed to estimate both the potential and curl parts of the magnetospheric electric field, the value of the elec tromagnetic energy entering the plasma sheet in the magnetotail, and t he rate of Joule heating in the ionosphere based on data on the dynami cs of the auroral electrojets.