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| Titel |
Storm-time meridional flows: a comparison of CINDI observations and model results |
| VerfasserIn |
M. Hairston, N. Maruyama, W. R. Coley, R. Stoneback |
| 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 ; 32, no. 6 ; Nr. 32, no. 6 (2014-06-17), S.659-668 |
| Datensatznummer |
250121072
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| Publikation (Nr.) |
 copernicus.org/angeo-32-659-2014.pdf |
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| Zusammenfassung |
| During a large geomagnetic storm, the electric field from the polar ionosphere
can expand far enough to affect the mid-latitude and equatorial electric
fields. These changes in the equatorial zonal electric field, called the
penetration field, will cause changes in the meridional ion flows that can be
observed by radars and spacecraft. In general this E × B
ion flow near the equator caused by the penetration field during
undershielding conditions will be upward on the dayside and downward on the
nightside of the Earth. Previous analysis of the equatorial meridional flows
observed by CINDI instrument on the C/NOFS spacecraft during the
26 September 2011 storm showed that all of the response flows on the dayside
were excess downward flows instead of the expected upward flows. These
observed storm-time responses are compared to a prediction from a
physics-based coupled model of thermosphere–ionosphere–inner-magnetosphere in
an effort to explain these observations. The model results suggest that the
equatorial downward flow could be attributed to a combined effect of the
overshielding and disturbance dynamo processes. However, some discrepancy
between the model and observation indicates a need for improving our
understanding of how sensitive the equatorial electric field is to various
model input parameters that describe the magnetosphere–ionosphere coupling
processes. |
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