Transpolar Arcs During a Prolonged Radial Interplanetary Magnetic Field Interval

Transpolar arcs (TPAs) are believed to predominantly occur under northward interplanetary magnetic field (IMF) conditions with their hemispheric asymmetry controlled by the Sun-Earth (radial) component of IMF. In this study, we present observations TPAs that appear in both northern and southern hemispheres even during a prolonged interval radially oriented The Defense Meteorological Satellite Program (DMSP) F16 Thermosphere Ionosphere Mesosphere Energetics Dynamics (TIMED) satellites observed on dawnside polar cap (one TPA structure hemisphere two hemisphere) an nearly earthward-oriented IMF October 29, 2005. one associated electron ion precipitation mostly sunward plasma flow (with shears) relative surroundings. Meanwhile, other is electron-only antisunward its Our indicate following: (a) formation not limited conditions; (b) can be located closed lines rooted open connected draped over magnetopause. We believe presented here result indirect direct processes solar wind energy transfer high-latitude ionosphere.