Field-aligned current signature in the dusk magnetosphere by INTERBALL-AU and POLAR

The POLAR and INTERBALL-AU spacecrafts magnetic field experiments allow investigation of the time-spatial variation of field-aligned current structures at mid and high altitudes. The study includes two intervals over north high latitudes in the dusk magnetosphere: (1) 10 January 09 – 11 UT (consecutive transits) and (2) 11 January, 03 – UT (nearly conjugate situation at 04:30 UT). By using both spacecraft, the identification of current regions is more confident. On January 11 cycles of the polarization reversal of small-scale disturbances in the poleward portion of region R1 have been detected at high and mid altitudes.