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| Titel |
Magnetospheric convection from Cluster EDI measurements compared with the ground-based ionospheric convection model IZMEM |
| VerfasserIn |
M. Forster, Y. I. Feldstein, S. E. Haaland, L. A. Dremukhina, L. I. Gromova, A. E. Levitin |
| 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 ; 27, no. 8 ; Nr. 27, no. 8 (2009-08-07), S.3077-3087 |
| Datensatznummer |
250016615
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| Publikation (Nr.) |
 copernicus.org/angeo-27-3077-2009.pdf |
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| Zusammenfassung |
| Cluster/EDI electron drift observations above the Northern and Southern polar
cap areas for more than seven and a half years (2001–2008) have been used
to derive a statistical model of the high-latitude electric potential
distribution for summer conditions.
Based on potential pattern for different orientations of the interplanetary
magnetic field (IMF) in the GSM y-z-plane, basic convection pattern (BCP)
were derived, that represent the main characteristics of the electric
potential distribution in dependence on the IMF.
The BCPs comprise the IMF-independent potential distribution as well as
patterns, which describe the dependence on positive and negative IMFBz and
IMFBy variations.
The full set of BCPs allows to describe the spatial and temporal variation
of the high-latitude electric potential (ionospheric convection) for any
solar wind IMF condition near the Earth's magnetopause within reasonable ranges.
The comparison of the Cluster/EDI model with the IZMEM ionospheric convection
model, which was derived from ground-based magnetometer observations, shows
a good agreement of the basic patterns and its variation with the IMF.
According to the statistical models, there is a two-cell antisunward convection
within the polar cap for northward IMFBz+≤2 nT, while for increasing
northward IMFBz+ there appears a region of sunward convection within the
high-latitude daytime sector, which assumes the form of two additional
cells with sunward convection between them for IMFBz+≈4–5 nT.
This results in a four-cell convection pattern of the high-latitude convection.
In dependence of the ±IMFBy contribution during sufficiently strong
northward IMFBz conditions, a transformation to three-cell convection
patterns takes place. |
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