CHECKING TWO-DIMENSIONAL SYMMETRIC MODEL OF RING CURRENT BY THE EFFECTS OF EQUATORIAL RING CURRENTS ON COSMIC RAY

Using the data from 11 ground-based super neutron monitors, this paper deals with the effects of equatorial ring currents on cosmic rays, which include that of storm-time increases and cut off rigidities in the analysis of this paper, during periods of six geomagnetic storms of 1984-1989. It is shown that the storm-time increases are due to the existence of westward equatorial ring currents developing or intensifying during geomagnetic storms. The storm-time increases are of latitude and local time dependence and the intensifying ring currents can cause the depression of cosmic ray cutoff rigidities. By comparing the storm-time increases and the registrations of H-component recorded by Beijing Standard Seismic Station. It can be seen that they correlate negatively with each other. On the basis of two-dimensional symmetric model of ring current, it is also shown that, except some very large storms, the expected decreases of H-component originated from a ring current which are calculated with this model are in good agreement with the actual observations on the ground.