Report Upon The End Of The GEM Tail-Substorm Campaign

Disturbances of the space environment are a critical aspect of Space Weather and of the NSF Geospace Environment Modeling (GEM) program. Other than for the the stormtime ring current, which forms within the inner magnetosphere, the primary space weather disturbances occur within the plasma sheet of the magnetotail and couple along magnetic field lines to the auroral ionosphere. At the time of inception of the GEM Tail-Substorm (TS) campaign, the substorm was the primary type of plasma sheet disturbance that was generally recognized. Hence, the Strategies for the Tail-Substorm Campaign (ed. by W. J. Hughes, Published by Boston University), completed in July 1993, emphasized the study of substorms, though it was also recognized that there are large temporal variations in plasma sheet flow, which were thought to play an important aspect of tail dynamics.