Extended period of low density solar wind - ground geomagnetic signatures

Abstract

Earth encountered a very long duration extremely low density event during February 2004. The magnetopause was pushed away from the earth and magnetospheric current systems were modified. Geomagnetic data from ground stations and geostationary satellite are examined. It is seen that the diurnal variation at all the locations is attenuated during this event. The substorm activity is subdued and restricted to very high latitudes. ULF pulsations could not be traced out in the ground magnetic data.