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| Titel |
THEMIS observations of earthward convected flux ropes triggering field dipolarization/substorm expansion and associated particle energization |
| VerfasserIn |
I. I. Vogiatzis, O. E. Malandraki, Q.-G. Zong, X.-Z. Zhou, T. E. Sarris, E. T. Sarris, H. Zhang, T. A. Fritz |
| 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 ; 29, no. 11 ; Nr. 29, no. 11 (2011-11-24), S.2117-2130 |
| Datensatznummer |
250017131
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| Publikation (Nr.) |
 copernicus.org/angeo-29-2117-2011.pdf |
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| Zusammenfassung |
| We investigated a number of substorm events during major conjunctions of the THEMIS spacecraft
for the tail seasons of the mission. We present simultaneous observations from various instruments onboard the THEMIS
spacecraft during the events. We focus particularly on events when at least one of the THEMIS spacecraft is adjacent to
the neutral sheet where convectional plasma flows are observed. The events demonstrate clear dipolarization signatures accompanied by high-speed earthward plasma flows and intense wave activity.
We present evidence that flux ropes are embedded within the high-speed earthward convective plasma sheet flows. This fact has important
implications since the leading edge of the flux rope having south polarity can impulsively merge with the north
polarity field of the stretched magnetotail leading to mutual erosion of both magnetic structures. The merging of the
vertically oriented oppositely-directed field lines can lead to local cross-tail current reduction and flux rope
dissipation. These observations are very important in explaining the mechanism triggering near-Earth dipolarization and particle acceleration to
supra-thermal energies, since they can be associated with non-adiabatic conditions and breakdown of the frozen-in
condition in the near-Earth magnetotail similar to that taking place during magnetic reconnection in the
mid-tail. |
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