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Titel |
A note on the ring current in Saturn’s magnetosphere: Comparison of magnetic data obtained during the Pioneer-11 and Voyager-1 and -2 fly-bys |
VerfasserIn |
E. J. Bunce, S. W. H. Cowley |
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 ; 21, no. 3 ; Nr. 21, no. 3, S.661-669 |
Datensatznummer |
250014584
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Publikation (Nr.) |
copernicus.org/angeo-21-661-2003.pdf |
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Zusammenfassung |
We examine the residual
(measured minus internal) magnetic field vectors observed in Saturn’s
magnetosphere during the Pioneer-11 fly-by in 1979, and compare them with those
observed during the Voyager-1 and -2 fly-bys in 1980 and 1981. We show for the
first time that a ring current system was present within the magnetosphere
during the Pioneer-11 encounter, which was qualitatively similar to those
present during the Voyager fly-bys. The analysis also shows, however, that the
ring current was located closer to the planet during the Pioneer-11 encounter
than during the comparable Voyager-1 fly-by, reflecting the more com-pressed
nature of the magnetosphere at the time. The residual field vectors have been
fit using an adaptation of the current system proposed for Jupiter by Connerney
et al. (1981a). A model that provides a reasonably good fit to the Pioneer-11
Saturn data extends radially between 6.5 and 12.5 RS (compared with a
noon-sector magnetopause distance of 17 RS), has a north-south extent of
4 RS, and carries a total current of 9.6 MA. A corresponding model that
provides a qualitatively similar fit to the Voyager data, determined previously
by Connerney et al. (1983), extends radially between 8 and 15.5 RS
(compared with a noon-sector magnetopause distance for Voyager-1 of 23–24 RS),
has a north-south extent of 6 RS, and carries a total current of 11.5
MA.
Key words. Magnetospheric physics
(current systems, magnetospheric configuration and dynamics, planetary
magnetospheres) |
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