Abstract
It is well-known that the amplitude and phase of the Sq(H) variation show considerable variability from day to day. In this paper we consider one aspect of the phase variability—that associated with AQDs. AQDs (or “abnormal quiet days”) are defined as magnetically quiet days where the maximum excursion of H at a mid-latitude station on the poleward side of the focus occurs outside the “normal” time range 0830–1330 LST. Such days exhibit properties, many of which appear quite distinct from the properties of the “normal” Sq(H) variation. The properties of AQDs, and the proposals that have been made to explain them, are considered in detail. The consequences of these proposals and some problems which need to be addressed in order to obtain a fuller understanding of the dynamics of the ionosphere on AQDs are also discussed.
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© 1989 Birkhäuser Verlag, Basel
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Butcher, E.C. (1989). Abnormal Sq Behaviour. In: Campbell, W.H. (eds) Quiet Daily Geomagnetic Fields. Pageoph Topical Volumes. Birkhäuser Basel. https://doi.org/10.1007/978-3-0348-9280-3_10
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DOI: https://doi.org/10.1007/978-3-0348-9280-3_10
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