Tailward propagating cross-tail current disruption and dynamics of near-earth tail: A multi-point measurement analysis

The authors report on analysis of data from three satellites (GEOS-2, ISEE-1 and 2), located in the magnetotail at 6.6 to 13RE during a substorm which occured on March 4, 1979. Energetic particle data, and magnetometer data are analyzed. The substorm appears to have developed at 6 to 9RE, and then propogated tailward a disruption in the cross tail current at a velocity of150 to 250km/s. Observation of the auroral electrojet index shows intensifications, and magnetometer data indicate transverse field components, which are consistent with current flow earthward. This current feeds energy to the electrojet. In order to quantitatively interpret the field variations observed at GEOS-2 in geostationary orbit, the authors found it easiest to assume the current sheet is expanding in that region