Hydrogen Showers in the Auroral Region

Abstract

PREVIOUS investigations have shown that the hydrogen lines are usually absent from spectrograms of the auroral luminescence. Even when the stronger lines and bands are much over-exposed and also very faint lines appear, there may still be no trace of the H-lines visible on the spectrogram^1,2,3,4. This does not mean, however, that hydrogen may not occasionally appear in three regions. On the contrary, some years age I gave, for the luminous night clouds, an explanation³ based on the assumption that showers of hydrogen, coming from the sun, entered into the atmosphere and combined with oxygen, for example, in the atomic or ozone state, to form water vapour. At the altitude of the luminous night clouds (80 km.), the atmospheric pressure might be sufficiently great for the water vapour to condense and produce clouds of ice needles.