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IMF B(y) and day-night conductivity effects in the expanding polar cap convection modelDuring southward B(z) periods the open field line region in the ionosphere (polar cap) expands due to increased dayside merging. Ionospheric plasma flow patterns result which can be classified by the sign of the interplanetary magnetic field (IMF) B(y) component. In this paper, a time-dependent ionospheric convection model is constructed to simulate these flows. The model consists of a spiral boundary with a gap in it. The sign of the IMF B(y) component determines the geometry of the gap. A potential is applied across the gap and distributed around the boundary. A flow results which enters the polar cap through the gap and uniformly pushes the boundary outward. Results of the model show that B(y) effects are greatest near the gap and virtually unnoticeable on the nightside of the polar cap. Adding a day-night ionospheric conductivity gradient concentrates the polar cap electric field toward dawn. The resulting flow curvature gives a sunward component that is independent of B(y). These patterns are shown to be consistent with published observations.
Document ID
Document Type
Reprint (Version printed in journal)
Moses, J. J.
(Aerospace Corp. Los Angeles, CA, United States)
Gorney, D. J.
(Aerospace Corp. Space Sciences Laboratory, Los Angeles, CA, United States)
Siscoe, G. L.
(Aerospace Corp. Los Angeles, CA, United States)
Crooker, N. U.
(California, University Los Angeles, United States)
Date Acquired
August 13, 2013
Publication Date
February 1, 1987
Publication Information
Publication: Journal of Geophysical Research
Volume: 92
ISSN: 0148-0227
Subject Category
Accession Number
Funding Number(s)
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