Equatorial electrojet reversals and their relation to polar cusp movements during geomagnetic storms

Using ground based magnetic observations, Mukunda Rao et al. have shown that most of the changes in the electrojet during a partial counter-electrojet observed through backscatter recordings at Thumba are also indicated by a simple parameter δHST-(Hequat-Hlow lat) Storm Day-(Hequat-Hlow lat)Mean of IQ days In this report ΔHST is applied to the storm events of 17-19 Sept. 1979 and 16 Feb. 1980. Both the events register a close correlation between ΔHST variations and the polar cusp movement, similar to those shown by back-scatter radar observations. Thus it appears that the ground based magnetic observations at the equator can also be used as a relatively simple and inexpensive means of studying polar cusp movements. © 1989.