Electron number densities in auroral irregularities: Comparison of backscatter and satellite data

Abstract

Explorer 20 topside sounder electron number density data are compared with simultaneous auroral backscatter data obtained at College, Alaska. The results show that auroral precipitation produces electron number-density fluctuations that are large in amplitude (of the order of 2x to 5x ambient) and small in geographic size (of order 1–10 km), along with a general increase in the ionospheric electron number density within the latitudinal region containing the precipitation. The increased electron number density appears to be the result of ionization (primary and secondary) produced by auroral particles within an altitude range of several hundred kilometers around the satellite.