X-Ray Spectrophotometric Remote Sensing of Diffuse Auroral Ionization

Auroral electron precipitation produces both E-region ionization and bremsstrahlung x rays. In a set of coordinated observations these atmospheric effects of electron precipitation were measured simultaneously by the x-ray sensor on the DMSPF2 spacecraft and by the incoherent-scatter radar at Chatanika, Alaska. In all data sets there was good agreement between the locations of the x-ray source regions and the regions of enhanced E-region ionization. Detailed comparisons were made between the measured and derived altitude profiles of ionization for two auroral conditions, a pre-midnight auroral band and a sunlit diffuse aurora. These comparisons validate the ability to derive auroral ionization from satellite-based x-ray measurements. Keywords Aurora, Bremsstrahlung x rays, Ionosphere, Remote sensing.