J. Hanumath Sastri
Indian Institute of Astrophysics, Bangalore 560 034, India
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.
Keywords: interplanetary (IP) shocks - geomagnetic storm sudden commencement (ssc)/sudden impulse (si) - ground-level effects at equatorial and low latitudes - polar ionosphere - low latitude ionosphere electrical coupling