Effects of high‐latitude conductivity on observed convection electric fields and Birkeland currents

摘要: Relationships between convective electric fields, Birkeland currents, and ionospheric conductivity at high latitudes are investigated by using simultaneous measurements of magnetic fields electron fluxes from the S3-2 satellite. Cases in which polar cap is sunlight darkness studied to assess importance conductivity. We find that when high, as it normally auroral zones sunlit cap, current sheets exist deflect field approximately direction convection, typically antisunward caps sunward zones. Under winter conditions (a dark ionosphere), no large-scale deflection lines found cap. Magnetic deflections zone result region 1/region 2 systems discussed Iijima Potemra (1976). In cases studied, 1 currents not observed extend significantly poleward reversal. interpret this indicating existence strong gradients near boundary oval, even conditions. Deflections summer first reported McDiarmid et al. (1978), serve link high-latitude generator load. Two types linkage appear data; (1) Region greater than with excess flowing across dawn dusk. (2) An extra set field-aligned clearly detached those entirely evidence for convection on closed threading layer, cited inconclusive. With our more complete data there some altitudes a but such only modest few kilovolts) potential drop layer insignificant currents.