Magnetospheric Compression Signatures of Traveling Convection Vortex Events

Most dayside, high-latitude ionospheric traveling convection vortices (TCVs), as observed in ground based magnetometer measurements, are accompanied by variations in the magnetic field strength at geosynchronous orbit. Similar compressional signatures in Equatorial ground-based magnetic observations have also been reported for many cases. A comprehensive understanding of these signatures and their relation to the TCV events, however, is still lacking. We present here the results of a systematic analysis of these relationships. The geosynchronous and low-latitude ground-based magnetic signatures for more than 40 TCV events identified in the Greenland and MACCS magnetometer data during 1998 have been analyzed. The results are compared to theoretical predictions for the relationships based on field aligned current generation by propagating localized compressions at the magnetopause. Further, the upstream solar wind conditions for the events are analyzed and interpreted in terms of predictions for occurrence, propagation direction and speed of magnetopause oscillations.