Geomagnetic latitude aspects of the effect of the interplanetary parameters on geomagnetic storms

Summary

In this work the previous author's results concerning the geomagnetic effect of the interplanetary parameters in dependence on geomagnetic latitude are verified, complemented and presented with better accuracy. Data of 7 intensive storms recorded in 1973–79 at 5 observatories with slight differences in local time and with the appropriate latitude distribution limited by real possibilities have been analysed. Even in these cases the derived values of the constants determining the dependence of storm-time variations of the geomagnetic field upon both the dynamic pressure of the solar wind(P) and the interplanetary electric field(E_y) vary relatively regularly with geomagnetic latitude. The anomaly of Dst and DR-variations from the Almeria Observatory (AE) evident in some intensive storms is pointed out here. Unlike the previous work the time characteristics (τ) of the ring current decay have been studied from the standpoint of the main (τ_m) and recovery (τ_r) phases of the storm. This yields higher values of τ_r as compared to τ from the above mentioned work. On the other hand, a large decrease in the values of τ_r was observed in some cases at a latitude of about 40°, as in the earlier study. Actually this phenomenon does not occur in all intensive storms as could be expected. As to the investigated storms, τ_m seems to be independent of geomagnetic latitude and much lower in its magnitude than τ_r.