Simultaneous Current Patterns of Polar Magnetic Storms (D_p-Field) in the Northern and Southern Polar Regions during IGY

Abstract

The average patterns of equivalent ionospheric current system of polar magnetic storms (D_p-field) for both northern and southern polar regions are constructed by analyzing exactly simultaneous data in both polar regions during the IGY period. Those data of magnetic storms are classified into two groups; i. e., severe storm for which K_p=7.2 and moderate storm for which K_p=4.3.
In both cases, the D_p patterns for the northern and southern polar regions are almost exactly symmetric with each other with respect to the geomagnetic coordinates, suggesting that the geomagnetic conjugacy well holds between the two polar regions.
Several remarks are made on mechanism of causation of the D_p field. It is emphasized, in particular, that the larger part of polar cap currents of the D_p field may be attributable to an enhancement of the S_q^p field by a stronger solar wind.