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Titel |
The magnetotail reconnection region in a global MHD simulation |
VerfasserIn |
T. V. Laitinen, T. I. Pulkkinen, M. Palmroth, P. Janhunen , H. E. J. Koskinen |
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 ; 23, no. 12 ; Nr. 23, no. 12 (2005-12-23), S.3753-3764 |
Datensatznummer |
250015438
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Publikation (Nr.) |
copernicus.org/angeo-23-3753-2005.pdf |
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Zusammenfassung |
This work investigates the nature and the role of magnetic
reconnection in a global magnetohydrodynamic simulation of the
magnetosphere. We use the Gumics-4 simulation to study
reconnection that occurs in the near-Earth region of the current
sheet in the magnetotail. We locate the current sheet surface and
the magnetic x-line that appears when reconnection starts. We
illustrate the difference between quiet and active states of the
reconnection region: variations in such quantities as the current
sheet thickness, plasma flow velocities, and Poynting vector
divergence are strong. A characteristic feature is strong
asymmetry caused by non-perpendicular inflows. We determine the
reconnection efficiency by the net rate of Poynting flux into the
reconnection region. The reconnection efficiency in the simulation
is directly proportional to the energy flux into the magnetosphere
through the magnetopause: about half of all energy flowing through
the magnetosphere is converted from an electromagnetic into a
mechanical form in the reconnection region. Thus, the tail
reconnection that is central to the magnetospheric circulation is
directly driven; the tail does not exhibit a cycle of storage and
rapid release of magnetic energy. We find similar behaviour of the
tail in both synthetic and real event runs. |
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