PROGRESSING POLAR CONVECTION DISTURBANCES - SIGNATURE - SIGNATURE OF AN OPEN MAGNETOSPHERE

On basis of comparison of data collected from geomagnetic observatorie s in the polar regions with solar wind data collected by the IMP 8 sat ellite, the characteristic patterns for the dynamical interaction of t he solar wind with the Earth's magnetosphere have been found for vario us interplanetary conditions. The interplanetary magnetic field (IMF) is a key parameter for the interaction. The variations in the dayside ionospheric currents associated with changes in the IMF B(Y) component often produces recognizable signatures in the ground magnetic variati ons. These signatures help to identify related space and ground data s ets. An important element for the interpretation of the geomagnetic si gnatures is their dynamical appearance as seen from latitudinally exte nded chains of stations in the polar cap. The frequent observations of poleward progressing polar convection disturbances during IMF B(Z) < 0 conditions strongly support the concept of an ''open'' magnetosphere during southward directed IMF.