The NII 2143A doublet has been observed in the earth's dayglow with a rocket spectrometer at an altitude of 200 km. The slant column emission rate of this airglow is 333±67 Rayleighs at a zenith angle of 87.6°. The likely excitation mechanisms are photoionization of molecular nitrogen by solar extreme ultraviolet radiation and photoelectron impact excitation of molecular nitrogen.
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Barth et al. (1982) studied this question.