Ionospheric convection and equivalent ionospheric currents in the dayside high-latitude winter ionosphere

Ionospheric convection inferred from Super Dual Amoral Radar Network (Super DARN) HF radar measurements is compared with an equivalent ionospheric conv ection derived from ground magnetometer data in the dayside winter high-lat itude ionosphere. Although there was general agreement between observed con vection patterns produced by radars and magnetometers, there were significa nt differences in details. The orientation of equivalent convection vectors inferred from magnetic data was often opposite to the convection vectors d etermined by the SuperDARN radars in the poleward part of the convection vo rtex structure, though the agreement was reasonable in its equatorward part . The magnitudes of convection vectors determined from radar data and those inferred from magnetometer data were often different. The observed differe nces are attributed to strong horizontal inhomogeneity in the ionospheric c onductivity distribution for winter conditions. It is possible that magneti c disturbances in the dark high-latitude ionosphere are strongly affected b y field-aligned currents at the terminator that separates regions of the su nlit highly conducting ionosphere and dark poorly conducting ionosphere.