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| Titel |
Search for an onset mechanism that operates for both CMEs and substorms |
| VerfasserIn |
G. L. Siscoe, M. M. Kuznetsova, J. Raeder |
| 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. 8 ; Nr. 27, no. 8 (2009-08-12), S.3141-3146 |
| Datensatznummer |
250016619
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| Publikation (Nr.) |
 copernicus.org/angeo-27-3141-2009.pdf |
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| Zusammenfassung |
| Substorms and coronal mass ejections have been cited as
the most accessible examples of the explosive energy conversion phenomenon
that seems to characterize one of the behavior modes of cosmic plasmas. This
paper addresses the question of whether these two examples – substorms and
CMEs – support or otherwise the idea that explosive energy conversion is the
result of a single process operating in different places and under different
conditions. As a candidate mechanism that might be common to both substorms
and CMEs we use the Forbes catastrophe model for CMEs because before testing
it appears to have the potential, suitably modified, to operate also for
substorms. The essence of the FCM is a sudden onset of an imbalance of the
forces acting on an incipient CME. The imbalance of forces causes the CME to
start to rise. Beneath the rising CME conditions develop that favor the
onset of magnetic reconnection which then releases the CME and assists its
expulsion. Thus the signature of the FCM is a temporally ordered sequence in
which there is first the appearance of force imbalance which leads to upward
(or outward) motion of the CME which leads to magnetic reconnection under it
which expedites rapid expulsion. We look for the FCM signature in the output
of two global magnetospheric MHD simulations that produce substorm-like
events. We find the ordered sequence of events as stated but with a
significant difference: there is no plasmoid prior to the onset of rapid
reconnection, that is, there is no counterpart to the incipient CME on which
an imbalance of forces acts to initiate the action in the FCM. If this
result – that rapid tailward motion precedes the rapid reconnection of
substorm expansion – is ultimately verified by other studies, it suggests
that a description of the cause of substorm expansion should identify the
cause of the preceding rapid tailward motion, since this leads necessarily
to rapid reconnection, whatever the reconnection mechanism turns out to be.
Clearly then, it is important to identify the cause of the preceding
tailward motion. |
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