Physical processes underlying the geomagnetic effects of solar wind dynamic pressure (Pd) variations

Abstract

A concise review of recent studies of the ground-level geomagnetic storm sudden commencements (ssc's)/positive sudden impulses (si's) observed in the dip equatorial region and at low latitudes is presented highlighting the in- cremental additions to our empirical knowledge of the characteristics of ssc's/si's and understanding of the physical processes responsible for them.