A Study of the November 15, 1993 Transpolar Arc

An arc observed at Eureka (88.9°N, 318°E CGM) on November 15, 1993, was also observed at Resolute Bay (84.5°N, 316°E CGM) and Cambridge Bay (77.6°N, 306°E CGM) and seen to extend from the central polar cap to the nightside oval. The auroral activity continued for 10 hours with its maximum intensity up to 20 kR (557.7 nm). The transpolar arc was mapped into the magnetotail by using Tsyganenko' s magnetic field model (T89). It is found that the source region was located at central plasma sheet boundary layer and extended to the tail lobe. It is also found that there is a sunward electrojet along the transpolar arc, based on analysis of magnetic signatures. The arc occurred during a period of strongly northward IMF Bz and time varying By, from negative to positive, which controlled the motion of the transpolar arc in the dawn-dusk direction.