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| Titel |
Flux closure during a substorm observed by Cluster, Double Star, IMAGE FUV, SuperDARN, and Greenland magnetometers |
| VerfasserIn |
S. E. Milan, J. A. Wild, B. Hubert, C. M. Carr, E. A. Lucek, J. M. Bosqued, J. F. Watermann, J. A. Slavin |
| 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 ; 24, no. 2 ; Nr. 24, no. 2 (2006-03-23), S.751-767 |
| Datensatznummer |
250015508
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| Publikation (Nr.) |
 copernicus.org/angeo-24-751-2006.pdf |
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| Zusammenfassung |
| We examine magnetic flux closure during an extended
substorm interval on 29 August 2004 involving a two-stage onset and
subsequent re-intensifications. Cluster and Double Star provide observations
of magnetotail dynamics, while the corresponding auroral evolution,
convection response, and substorm current wedge development are monitored by
IMAGE FUV, SuperDARN, and the Greenland magnetometer chain, respectively.
The first stage of onset is associated with the reconnection of closed flux
in the plasma sheet; this is accompanied by a short-lived auroral
intensification, a modest substorm current wedge magnetic bay, but no
significant ionospheric convection enhancement. The second stage follows the
progression of reconnection to the open field lines of the lobes;
accompanied by prolonged auroral bulge and westward-travelling surge
development, enhanced magnetic bays and convection. We find that the tail
dynamics are highly influenced by ongoing dayside creation of open flux,
leading to flux pile-up in the near-tail and a step-wise down-tail motion of
the tail reconnection site. In all, 5 dipolarizations are observed, each
associated with the closure of ~0.1 GWb of flux. Very simple
calculations indicate that the X-line should progress down-tail at a speed
of 20 km s-1, or 6 RE between each dipolarization. |
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