Density irregularities observed near the plasmapause by the CRRES satellite at the onset of magnetic disturbances

High resolution (8-sec) cold plasma density data derived from plasma wave observations is available for over 1000 orbits of the CRRES satellite (1990-1991). We will present the results of a study of density irregularities near the plasmapause with special emphasis on the midnight to dawn local time sectors during the onset of magnetic disturbances. We will examine where and under what geophysical conditions irregularities occur in an attempt to understand the role they may play in the shedding of plasma by the plasmasphere.