Title: Neutral wind modifications above 150 km altitude associated with the polar substorm
Abstract: Ion and neutral clouds have been released at altitudes between ~ 150 and ~ 180 km, from a range in the auroral zone (ESRANGE), Kiruna, Northern Sweden) and from a range at sub-auroral latitude (South Uist, Outer Hebrides, Northern Scotland). Data obtained towards the end of April in Kiruna, and in mid-May in South Uist, near local midnight, when the ionosphere is almost continuously sunlit, have been used to study the behaviour of neutral winds at a time when a high level of ionization is maintained throughout the night. Our analysis of the behaviour of neutral winds during magnetically disturbed times suggests that auroral heating is the prevailing mechanism in modifying the quiet time wind pattern. These conclusions are further supported by our analysis of published data on artificial ion and neutral clouds released by the Max Planck Institut (Garsching) and the NASA (Goddard) groups. We find that the behaviour of clouds released at higher (⪞ 180 km) altitudes, as well as at different latitudes, can also be accounted for in terms of the perturbation to the neutral wind system introduced by additional auroral heating during magnetically disturbed times. At quiet times, the observed neutral winds are quite close, in magnitude and direction, to those computed on the basis of the exospheric temperature distribution proposed by Jacchia.
Publication Year: 1974
Publication Date: 1974-11-01
Language: en
Type: article
Indexed In: ['crossref']
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Cited By Count: 22
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