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Titel |
Longitudinal development of a substorm brightening arc |
VerfasserIn |
K. Shiokawa, A. Ieda, A. Nakajima, K. Sakaguchi, R. Nomura, T. Aslaksen, M. Greffen, E. Spanswick, E. Donovan, S. B. Mende, J. McFadden, K.-H. Glassmeier, V. Angelopoulos, Y. Miyashita |
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 ; 27, no. 5 ; Nr. 27, no. 5 (2009-05-04), S.1935-1940 |
Datensatznummer |
250016511
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Publikation (Nr.) |
copernicus.org/angeo-27-1935-2009.pdf |
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Zusammenfassung |
We present simultaneous THEMIS-ground observations of longitudinal (eastward)
extension of a substorm initial-brightening arc at Gillam (magnetic latitude:
65.6°) at 08:13 UT on 10 January 2008. The speed of the eastward arc
extension was ~2.7 km/s. The extension took place very close to the
footprints of the longitudinally separated THEMIS E and D satellites at
~12 RE. The THEMIS satellites observed field dipolarization, weak
earthward flow, and pressure increase, which propagated eastward from E to D
at a speed of ~50 km/s. The THEMIS A satellite, located at 1.6 RE
earthward of THEMIS E, observed fluctuating magnetic field during and after
the dipolarization. The THEMIS E/D observations suggest that the longitudinal
extension of the brightening arc at substorm onset is caused by earthward
flow braking processes which produce field dipolarization and pressure
increase propagating in longitude in the near-earth plasma sheet. |
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