The magnetospheric plasma tail

The structural nature of the earth's plasmasphere at onset and immediately following an intense magnetic storm is examined. Thermal proton density measurements by the RF ion mass spectrometer on the low altitude polar orbiting satellite OGO-4 were compared on five consecutive nightside passes during the early recovery stage of an intense storm occuring in September 1967. Observational results revealed (1) characteristic termination of the dense plasmapause, (2) secondary enhancement of the ion density poleward of the first abrupt plasmapause, and (3) an elongated plasma tail during the recovery phase of the storm.