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| Titel |
THEMIS and ground-based observations of successive substorm onsets following a super-long growth phase |
| VerfasserIn |
J.-M. Liu, Y. Kamide, B.-C. Zhang, H.-Q. Hu, H.-G. Yang |
| 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 ; 31, no. 5 ; Nr. 31, no. 5 (2013-05-06), S.835-843 |
| Datensatznummer |
250019037
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| Publikation (Nr.) |
 copernicus.org/angeo-31-835-2013.pdf |
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| Zusammenfassung |
| We present four successive substorm events, which followed
a super-long, as long as 9 h, growth phase on 5 December 2008,
observed by the Time History of Events and Macroscale Interaction during
Substorms (THEMIS) and the GOES 11 satellite with simultaneous coverage by
the Alaska and THEMIS ground magnetometers. Several interesting and unique
features were found for these cases. The interplanetary magnetic field was
steadily southward and the solar wind speed was slow, less than 450 km s−1,
which are thought to drive the long growth phase for the following onsets.
At least four substorm expansion onsets occurred, including a double-onset
event, which appears to be a challenge to the reconnection hypothesis for
double-onset substorm and favored an instability mechanism for the onsets
and could not be explained by the two neutral line models. For the onsets at
09:32 UT and 09:42 UT, the dipolarization signature was observed by GOES 11,
which was located earthward of THEMIS C and THEMIS B. THEMIS C satellite
caught a delayed and much weaker signature 1–3 min after GOES 11. THEMIS
B observed no relating signature. These observations provide us with direct
evidence that these events initiated at the near-earth region. The
observations of THEMIS C and THEMIS B around the onsets favor the near-earth
instabilities model for substorm onset. |
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