Parallel electric fields produced by the ionospheric injection

Abstract. It is well known that there exists a thin layer in lower boundary of the ionosphere between altitudes of 80 km and 140 km in which collisional ions and collisionless electrons mix. Local breakdown of charge neutrality may be initiated in this layer by electric fields from the magnetosphere as well as by electric fields generated there by the local neutral winds. The breakdown may be momentarily canceled by the Pedersen currents, but a complete neutralization is prevented because some ionospheric plasmas are released as outflows by parallel electric fields. Those parallel electric fields are produced by inherent plasma processes in the polar ionosphere and act as auroral drivers in the topside ionosphere.