Growth and decay of the ring current and the polar electrojets

Abstract

It is shown that, although intense polar magnetic substorms tend to occur frequently when the ring current is rapidly growing, there is a tendency for the ring current to grow prior to the growth of well-defined polar magnetic substorms. It is shown also that earlier estimates of the rate of energy injection to produce the ring current are too low, because the simultaneous dissipation has not been considered. It is shown that, when this is taken into consideration, an unreasonably high energy conversion would be necessary to produce the ring current if the energy were carried by protons in the solar plasma.