Non-Maxwellian electron distributions in the D region during artificial heating (Paper II): Electron cooling rates

Abstract. This paper investigates how non-Maxwellian distributions of heated electrons modify the macroscopic properties of the electron gas in the D region. Adjusted electron cooling rates for vibrational excitation of molecular nitrogen and molecular oxygen, as well as excitation of fine structure levels in atomic oxygen, are presented. These electron cooling rates are compared to Maxwellian cooling rates from previous studies by Pavlov (1998a), Campbell et al. (2004) , Pavlov (1998b) and Pavlov (1998). We find that the electron cooling rates for vibrational excitation of molecular nitrogen and excitation of fine structure levels in atomic oxygen are more affected by deviations from Maxwellian compared to the cooling rates for vibrational excitation of molecular oxygen. This is due changes in the electron phase space density, where inelastic collision between electrons and neutrals leads to redistribution of electrons.