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| Titel |
Observations of IMF coherent structures and their relationship to SEP dropout events |
| VerfasserIn |
L. Trenchi, R. Bruno, R. D'Amicis, M. F. Marcucci, D. Telloni |
| 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. 8 ; Nr. 31, no. 8 (2013-08-06), S.1333-1341 |
| Datensatznummer |
250086087
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| Publikation (Nr.) |
 copernicus.org/angeo-31-1333-2013.pdf |
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| Zusammenfassung |
The solar energetic particle (SEP) events from impulsive solar flares are often
characterized by short-timescale modulations affecting, at the same time,
particles with different energies. Several models and simulations suggest
that these modulations are observed when SEPs propagate through magnetic
structures with a different connection with the flare site. However, in situ
observations rarely showed clear magnetic signatures associated with these
modulations.
In this paper we used the Grad–Shafranov reconstruction to perform a detailed
analysis of the local magnetic field topology during the SEP event of 9–10
January 1999, characterized by several SEP dropouts. An optimization
procedure is used to identify, during this SEP event, the magnetic structures
which better satisfy the Grad–Shafranov assumptions and to evaluate the
direction of their invariant axis.
We found that these two-dimensional structures, which are flux ropes or
current sheets with a more complex field topology, are generally associated
with the maxima in the SEP counts. This association suggests that the SEPs
propagate within these structures and, since their gyration radii is much
smaller than the transverse dimension of these structure, cannot escape from
them. |
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