Abstract Thin sporadic E-layers are usually explained in terms of the wind shear mechanism. During the last few years, however, two other mechanisms have been proposed which may create similar layers in some circumstances. In this paper all three mechanisms are discussed and results obtained using the EISCAT radar are reviewed. The EISCAT UHF experiments designed for sporadic E research allow the measurement of both the power profile and the autocorrelation function with a range resolution of 300–600 m. The results show that the wind shear mechanism works at auroral latitudes creating a conventional descending sporadic E-layer which is most probably associated with the semidiurnal component of the solar tide. Velocity measurements show quick changes in the neutral wind which destroy the layer and redistribute the long-lived ions in the E region. Wind structures due to gravity waves are observed to create sporadic E-layers which are not of the sequential type. Some evidence is also found that a sporadic E-layer can be formed by a strong auroral electric field in the absence of wind shears. In composition studies both heavy and light ions are found in variable concentrations within the layers.
Studies of sporadic E-layer using the EISCAT incoherent scatter radar
Advances in Space Research ; 9 , 5 ; 73-81
01.01.1989
9 pages
Aufsatz (Zeitschrift)
Elektronische Ressource
Englisch
Studies of the E-Region Ion-Neutral Collision Frequency Using the EISCAT Incoherent Scatter Radar
British Library Conference Proceedings | 1996
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