Correlation between Cusp Field-Aligned Currents and Interplanetary Magnetic Field (b. Electric Fields and Current System) (Proceedings of the First Symposium on Coordinated Observations of the Ionosphere and the Magnetosphere in the Polar Regions (Part I))

Abstract

From the analysis of vector magnetometer data of more than 200 passes of TRIAD that were recorded at McMurdo, Antarctica, during the winter season, 1974, the principal characteristics of the cusp field-aligned currents (FAC) in the midday south polar region are determined: 1) Cusp type FAC's exist in the midday polar region that is separate from the region 1 (and 2) FAC regimes. No satisfactory explanation is obtained by attributing the cusp type FAC's to dislocation in latitude and or shift in longitude of the general distribution of the region 1 and 2 FAC's. 2) The demarcation line between the pre-noon type and the post-noon type cusp FAC's is controlled well by the polarity of IMF B_y. 3) There is a linear correlation between the intensity of the cusp FAC and the negative IMF B_z component. No clear relation was found between the cusp FAC intensity and the positive IMF B_z component.