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Title: Interhemispheric observations of nightside ionospheric electric fields in response to IMF B-z and B-y changes and substorm pseudobreakup
Authors: Yeoman, T. K.
Lewis, R. V.
Khan, H.
Cowley, S. W. H.
Ruohoniemi, J. M.
First Published: 1-Aug-2000
Publisher: European Geosciences Union (EGU), Copernicus Publications, Springer Verlag (Germany)
Abstract: HF radar data during equinoctial, small IMF By conditions have enabled the ionospheric convection during the substorm growth phase and substorm pseudobreakup to be studied in both hemispheres. This has revealed both conjugate and non-conjugate convection behaviour during the substorm growth phase before and after the pseudobreakup onset. The nightside convection pattern is found to respond promptly to the southward turning of the interplanetary magnetic field (IMF) which impacts on the dusk flank of the magnetosphere due to an inclined phase front in the IMF in the case study presented. The subsequent interhemispheric observations of nightside convection are controlled by the IMF By polarity. The time scale for the response to changes in the IMF By component is found to be a little longer than for Bz, and the full impact of the IMF By is not apparent in the nightside convection until after substorm pseudobreakup has occurred. The pseudobreakup itself is found to result in a transitory suppression in the ionospheric electric field in both hemispheres. This flow suppression is very similar to that observed in HF radar observations of full substorm onset, with the exception of a lack of subsequent poleward expansion.
DOI Link: 10.1007/s00585-000-0897-x
ISSN: 0992-7689
eISSN: 1432-0576
Type: Journal Article
Rights: Archived with reference to SHERPA/RoMEO and publisher website. © European Geosciences Union 2000. Version of record:
Appears in Collections:Published Articles, Dept. of Physics and Astronomy

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