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Titel |
Global reconnection topology as inferred from plasma observations inside Kelvin-Helmholtz vortices |
VerfasserIn |
M. B. Bavassano Cattaneo, M. F. Marcucci, Y. V. Bogdanova, H. Rème, I. Dandouras, L. M. Kistler, E. Lucek |
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 ; 28, no. 4 ; Nr. 28, no. 4 (2010-04-01), S.893-906 |
Datensatznummer |
250016812
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Publikation (Nr.) |
copernicus.org/angeo-28-893-2010.pdf |
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Zusammenfassung |
During a long lasting period of northward interplanetary magnetic field and
high solar wind speed (above 700 km/s), the Cluster spacecraft go across a
number of very large rolled-up Kelvin-Helmholtz (KH) vortices at the dusk
magnetopause, close to the terminator. The peculiarity of the present event
is a particular sequence of ions and electrons distribution functions observed
repeatedly inside each vortex. In particular, whenever Cluster crosses the
current layer inside the vortices, multiple field-aligned ion populations
appear, suggesting the occurrence of reconnection. In addition, the ion data
display a clear velocity filter effect both at the leading and at the
trailing edge of each vortex. This effect is not present in the simultaneous
electron data. Unlike other KH studies reported in the literature in which
reconnection occurs within the vortices, in the present event the
observations are not compatible with local reconnection, but are accounted
for by lobe reconnection occurring along an extended X-line at the terminator
in the Southern Hemisphere. The reconnected field lines "sink" across the
magnetopause and then convect tailward-duskward where they become embedded in
the vortices. Another observational evidence is the detected presence of
solar wind plasma on the magnetospheric side of the vortices, which confirms
unambiguously the occurrence of mass transport across the magnetopause
already reported in the literature. The proposed reconnection scenario
accounts for all the observational aspects, regarding both the transport
process and the kinetic signatures. |
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