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| Titel |
Multi-instrument observations of nightside plasma patches under conditions of IMF Bz positive |
| VerfasserIn |
A. G. Wood, S. E. Pryse, H. R. Middleton, V. S. C. Howells |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
0992-7689
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| Digitales Dokument |
URL |
| Erschienen |
In: Annales Geophysicae ; 26, no. 8 ; Nr. 26, no. 8 (2008-08-05), S.2203-2216 |
| Datensatznummer |
250016179
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| Publikation (Nr.) |
 copernicus.org/angeo-26-2203-2008.pdf |
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| Zusammenfassung |
| Results are presented from two multi-instrument case studies showing patches
of cold, long-lived plasma in the winter nightside ionosphere during times
when the z-component of the Interplanetary Magnetic Field (IMF Bz) was
positive. These enhancements were coincident with the antisunward convective
plasma drift, flowing from polar to nightside auroral latitudes. In the
first case, on 5 December 2005 with IMF By negative, two regions of
enhanced electron density were observed extended in MLT in the magnetic
midnight sector separated by lower densities near midnight. It is likely
that the earlier enhancement originated on the dayside near magnetic noon
and was transported to the nightside sector in the convective flow, whilst
the later feature originated in the morning magnetic sector. The lower
densities separating the two enhancements were a consequence of a pair of
lobe cells essentially blocking the direct antisunward cross polar flow from
the dayside. A second case study on 4 February 2006 with IMF By
positive revealed a single nightside enhancement likely to have originated
in the morning magnetic sector. These multi-instrument investigations,
incorporating observations by the EISCAT radar facility, the SuperDARN
network and radio tomography, reveal that plasma flowing from the dayside
can play a significant role in the nightside ionosphere under conditions of
IMF Bz positive. The observations are reinforced by simulations of
flux-tube transport and plasma decay. |
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