Abstract
THE exact mode of excitation of the lines and bands in the auroral spectrum is not yet fully understood. Many attempts have been made to explain the spectrum, but none has been convincing1,2,3. The purpose of the present note is to offer a simple explanation of the auroral spectrum on the lines of the theory of emission of similar lines and bands from the luminescent layer of the night sky postulated by me some time ago4,5. Besides similarities, there are also differences between the two spectra ; but these are to be traced mostly to the difference in the atmospheric heights at which the two phenomena originate: the height of the most frequent occurrence of aurora is between 90 and 120 km. (regions D and E of the ionosphere), and the height of the luminescent layer of the night sky is 200–400 km. (region F of the ionosphere). The collisional frequency of the atmospheric particles, which affects the emission of the spectra, is about two orders higher in the lower than in the higher region.
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MITRA, S. The Auroral Spectrum. Nature 157, 692 (1946). https://doi.org/10.1038/157692a0
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DOI: https://doi.org/10.1038/157692a0
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