Equivalent ionospheric currents above Antarctica during the austral summer

• Published in: Antarctic Science
• Main Authors: Papitashvili, V.O., Feldstein, Ya.I., Levitin, A.E., Belov, B.A., Gromova, L.I., Valchuk, T.E.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Cambridge University Press (CUP) 1990
• Subjects: Geology; Ecology, Evolution, Behavior and Systematics; Oceanography; Antarctic; Austral; Antarc*; Antarctic Science; Antarctica
• Online Access: http://dx.doi.org/10.1017/s0954102090000360; https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0954102090000360

A regression analysis was carried out between the ground-based geomagnetic data from the southern polar regions (above −55° corrected geomagnetic latitude) and the interplanetary magnetic field (IMF) components in the geocentric solar-magnetospheric co-ordinate system and solar wind (SW) parameters. Hourly mean values of the geomagnetic field horizontal components H and D from 20 Antarctic observatories and automatic stations of 1978–80 and 1983–84 were examined. Regression coefficients were used as geomagnetic perturbation vectors which were rotated 90° clockwise to plot the equivalent current vector patterns in the “corrected geomagnetic latitude-magnetic local time” co-ordinates. The results which are described in the paper reflect geomagnetic phenomena associated with the IMF and SW parameters for the austral summer season only (November, December, January, February). It was found that, in general, global characteristics of the ionospheric convection patterns agree well for both hemispheres. Geomagnetic variations, which are generated by the interaction of the SW plasma and frozen-in IMF with Earth's magnetosphere, represent three types of equivalent current systems: a) two-vortex system with transpolar current from nightside to dayside, controlled by the “quasi-viscous” interaction and southward IMF; b) zonal current system, controlled by the azimuthal IMF; and c) two-vortex system with transpolar current from noon to midnight controlled by the northward IMF. The southern polar cap (above −75°), which was more densely packed with automatic magnetometers than the northern cap, permit us to investigate the fine structure of the high-latitude current systems in detail.