The Hot Fraction of Oxygen Atoms in the Earth’s Polar Upper Atmosphere—the Contribution of Odd Nitrogen Chemistry

Abstract— It has been shown quantitatively for the first time that the main source of hot oxygen atoms in the Earth’s polar atmosphere during strong geomagnetic storms are exothermic reactions of odd nitrogen chemistry activated by auroral electron precipitation, compared to direct dissociation of O2 by an electron impact. At altitudes of 500–600 km and above, the concentration of hot oxygen is 10–20% of the thermal concentration, which must be taken into account when calculating the atmospheric drag of low-orbit satellites, since the error in estimating the density of the atmosphere can reach values of up to 20%. The calculations were performed using kinetic Monte Carlo models for the conditions of the geomagnetic storm of November 9, 2004.