Simultaneous observation of electron fluxes, ionization, and luminosity in an aurora

Abstract

Electron energy spectra, number density of ambient electrons, and 5577 Å luminosity have been measured in a rocket which passed through a well-defined westward-moving auroral band embedded in a widespread diffuse glow. In the band there was excellent spatial correlation among the electron number density, the luminosity as seen from both the ground and the rocket, and the electron flux of energy 1–7 keV. A peak of higher-energy electrons apparently trailed the band by ~ 10 km. The electron fluxes appeared to be not quite sufficient to account for the observed electron number density, still less for the luminosity. Fluxes of electrons having energies of the order of 100 eV were observed, too large and too uncorrelated with the higher-energy electron fluxes to be secondaries produced in the atmosphere by the electrons of higher energy. Since 100-eV electrons cannot penetrate from above to such heights [Formula: see text], there is a suggestion that they must have been locally accelerated. When these electrons are included in the calculations, it is possible under certain assumptions to obtain quantitative agreement between electron flux, electron density, and 5577 Å photon production in the diffuse glow.