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| Titel |
Polar cap convection patterns inferred from EISCAT observations |
| VerfasserIn |
C. Peymirat, D. Fontaine |
| 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 ; 15, no. 4 ; Nr. 15, no. 4, S.403-411 |
| Datensatznummer |
250012726
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| Publikation (Nr.) |
 copernicus.org/angeo-15-403-1997.pdf |
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| Zusammenfassung |
| From data of the European incoherent scatter
radar EISCAT, and mainly from its tristatic capabilities, statistical models of
steady convection in the auroral ionosphere were achieved for various levels of
magnetic activity. We propose here to consistently extend these models to the
polar cap, by avoiding the use of a pre-defined convection pattern. Basically,
we solve the second-order differential equation governing the polar cap
convection potential with the boundary conditions provided by these models. The
results display the classical twin-vortex convection pattern, with the cell
centres around 17 MLT for the evening cell and largely shifted towards midnight
(3–3.5 MLT) for the morning cell, both slightly moving equatorward with
activity. For moderate magnetic activities, the convection flow appears
approximately oriented along the meridian from 10:00 MLT to 22:00 MLT, while in
more active situations, it enters the polar cap at prenoon times following the
antisunward direction, and then turns to exit around 21:00 MLT. Finally, from
these polar cap patterns combined with the auroral statistical models, we build
analytical models of the auroral and polar convection expected in steady
magnetic conditions. |
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