Polar cap dynamics according to observations of long-period geomagnetic pulsations

Polar cap radius is determined on the basis of the developed technique using characteristic differences in the intensity distribution of high-latitudinal long-period geomagnetic pulsations. Dependence of cap radius on the parameters of interplanetary medium and AE-index is investigated for quiet and perturbed conditions. On the basis of the potential difference across the cap (ΔU) is calculated, the relation of ΔU with Bz interplanetary magnetic field component and with solar wind velocity is considered, and the value of residual potential, which coincides with model calculations and direct measurements of the given parameter, is obtained