Cooling rate of thermal electrons by electron impact excitation of fine structure levels of atomic oxygen

Abstract. The atomic oxygen fine structure cooling rate of thermal electrons based on new effective collision strengths for electron impact excitation of the ground-state ³P fine-structure levels in atomic oxygen have been fitted to an analytical expression which is available to the researcher for quick reference and accurate computer modeling with a minimum of calculations. We found that at the F region altitudes of the ionosphere the new cooling rate is much less than the currently used fine structure cooling rates (up to a factor of 2-4), and this cooling rate is not the dominant electron cooling process in the F region of the ionosphere at middle latitudes.

Key words. Atmospheric composition and structure (thermosphere · composition and density) · Ionosphere (mid-latitude ionosphere; modelling and forecasting).