TEMPORAL BEHAVIOR OF ENERGY INJECTION INTO THE GEOMAGNETIC RING CURRENT.

The rate of energy injection into the geomagnetic ring current has been determined for the years 1958 and 1964 using a method based on Dst and knowledge of the decay rate for the ring current energy. At all levels of magnetic activity, the temporal behavior of the energy injection is similar to Dp in that it is burst-like; also there is a positive but imperfect correlation between Dp and the rate of energy injection into the ring current. The onset times of energy-injection bursts typically occur during the same hour or after the onset times of Dp bursts, and it is often possible to identify an injection burst as being associated with a particular Dp burst and then the peaks in both types of activity are simultaneous within one hour. During the quiet year of 1964, the average injection rate, on a monthly basis, was fairly constant and was near 1.2 × 1017 ergs sec−1. The rate during the active year 1958 was highly variable with the over-all average being 1.7 × 1017 ergs sec−1. Maximum hourly average injection rates of 1 × 1019 ergs sec−1 occurred during great magnetic storms. Although the injection of energy into the ring current, averaged over the entire ring, increases during a magnetospheric substorm, examination of longitudinal differences in the injection indicate temporary losses from the midnight and morning sectors at the onset of some substorms. Also it is found that when a magnetic storm follows a prolonged period of magnetic quiet, there is often precursor activity lasting 4 to 60 hours.