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| Titel |
Near-Earth magnetic signature of magnetospheric substorms and an improved substorm current model |
| VerfasserIn |
P. Ritter, H. Lühr |
| 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. 9 ; Nr. 26, no. 9 (2008-09-18), S.2781-2793 |
| Datensatznummer |
250016227
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| Publikation (Nr.) |
 copernicus.org/angeo-26-2781-2008.pdf |
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| Zusammenfassung |
| Based on a comprehensive catalogue with more than 4000 magnetospheric
substorm entries from the years 2000–2005, the spatial distribution of the
substorm-related magnetic signatures at mid and low latitudes around local
midnight was investigated. Superposed epoch analysis of a larger number of
recent observatory data from mid and low latitudes revealed a field strength
increase that is consistent with the results of earlier studies. For the
first time, the magnetic signature of the substorm current wedge formation is
studied also in near-Earth satellite data from CHAMP. The average maximal
deflection measured on board the satellite is smaller by a factor of 2 than
that determined from ground observations. The recurrence frequency of
substorms as well as the amplitude of their magnetic signature depends
strongly on the prevailing magnetic activity. The observed average
substorm-related magnetic field signatures cannot be described adequately by
a simple current wedge model. A satisfactory agreement between model results
and observations at satellite height and on ground can be achieved only if
the current reconfiguration scenario combines four elements: (1) the gradual
decrease of the tail lobe field, (2) the re-routing of a part of the
cross-tail current through the ionosphere, (3) eastward ionospheric currents
at low and mid latitudes driven by Region-2 field-aligned currents, and (4) a
partial ring current connected to these Region-2 FACs. |
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