Global distribution of electric fields and currents in the ionosphere produced by field-aligned currents of magnetospheric origin—I

Abstract

Numerical calculations are made for the electric field and current in the ionosphere, using several models of polewards j ∥(1) (Region 1) and equatorwards j ∥(2) (Region 2) field-aligned currents similar to those recently reported by Iijima and Potemra (1978) and assuming a uniform distribution of ionospheric conductivities. It is found that, when the intensity ratios J ∥(2) j ∥(1) at local times are small, or when the separation between Regions 1 and 2 in latitude is narrow, the Region 1 field-aligned currents have a predominant effect at middle and low latitudes on the intensity and direction of electric fields (currents) to the extent that the distribution of electric fields (currents) is sometimes reversed. In the polar cap region on the other hand, the distribution of the electric field and current is found to be mainly determined by the Region 1 field-aligned currents, although the intensity of the electric field and current is strengthened or weakened, depending on whether the ratios J ∥(2) j ∥(1) are small or large, respectively.