An interpretation of the auroral breakup

Abstract

A dynamical model of the magnetosphere is presented to account for the main morphological features of the aurora, and the auroral breakup in particular. The aurora is the result of an internal process in the magnetosphere. It is suggested that a fluting instability on the outer boundary of the ring current belt is responsible for auroral breakup. This instability leads to a rapid flow of the ring current plasma into the tail of the magnetosphere. Particular attention is focused on the mechanisms for energizing electrons, the dynamics of the fluting instability in the magnetosphere including the dissipative effects of the ionosphere, and the structure of the ring current belt. It is stressed that the aurora gets its energy from the DR (ring current) belt. It is shown that the asymmetry of the DR belt and the observed asymmetry of the radiation belts can be accounted for by the asymmetric injection of charged particles on the day side of the geomagnetic field.