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Titel |
Reconnection in a slow Coronal Mass Ejection |
VerfasserIn |
G. Poletto, A. Bemporad, F. Landini, M. Romoli |
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 ; 26, no. 10 ; Nr. 26, no. 10 (2008-10-15), S.3067-3075 |
Datensatznummer |
250016254
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Publikation (Nr.) |
copernicus.org/angeo-26-3067-2008.pdf |
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Zusammenfassung |
This paper aims at studying reconnection occurring in the
aftermath of the 28 May 2004, CME, first imaged by the LASCO (Large Angle and
Spectrometric Coronagraph) C2 at 11:06 UT. The CME was observed in White Light
and UV radiation: images acquired by the LASCO
C2 and C3 coronagraphs and spectra acquired by UVCS (Ultraviolet
Coronagraph Spectrometer) allowed us to identify the level at which
field lines, stretched outwards by the CME ejection, reconnect
below the CME bubble. As the CME propagates outwards, reconnection occurs at
increasingly higher levels. The process goes on at a low pace for several
hours: here we give the profile of the reconnection rate vs. heliocentric
distance over a time interval of ≈14 h after the CME onset,
extending estimates of the reconnection rate to larger distances than previously
inferred by other authors. The reconnection rate appears to decrease with
time/altitude. We also calculate upper and lower limits
to the density in the diffusion region between 4 and 7 R⊙
and conclude by comparing estimates of the classical and anomalous resistivity
in the diffusion region with the value inferred from the data. The latter
turns out to be ≥5 order of magnitudes larger than predicted by
classical or anomalous theories, pointing to the need of identifying the
process responsible for the observed value. |
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