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Richards et al. 1986
Richards, P.G., Torr, D.G. and Abdou, W.A. (1986). Effects of vibrational enhancement of N2 on the cooling rate of ionospheric thermal electrons. Journal of Geophysical Research 91: doi: 10.1029/JA091iA01p00304. issn: 0148-0227.

This study shows that the cooling rate of ionospheric thermal electrons by molecular nitrogen may be reduced by more than a factor of 3 as a result of the enhanced vibrational excitatin of N2 from a number of chemical sources. Moreover, under conditions of enhanced F region electron densities (Nc>106 cm-3), N2 may act as a small net source rather than sink of electron thermal energy. If the most commonly used electron cooling rates are correct, the influence of vibrational enhancement on the electron temperature is small because cooling through fine structure excitation of O is dominant below the altitude of the F2 peak electron density. However, recent measurements indicate that the cross sections used to evaluate the N2 cooling would be dominant, and the neglect of enhanced vibrational excitation of N2 would lead to an underestimate of about 100¿K in the thermal electron temperatures throughout the F region ionosphere at solar minimum. The effect on the electron temperature at solar maximum is small and confined to the region below the F2 peak density because of the enhanced ion cooling. Two new sources of N2 vibrational excitation are evaluated. One of these, the photoelectron excitation and subsequent deactivation of the A, B, C, and W triplet states of N2 is found to be a major source of N2 vibrational quanta. This source is several times larger than the direct (2.5 eV) photoelectron source above 250km. The second new source, charge exchange between N2+ and N2, is comparable to the other sources at high altitudes but is small below 200 km.

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Journal of Geophysical Research
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American Geophysical Union
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