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| Titel |
High-latitude field-aligned currents observed by Cassini in Saturn’s magnetosphere |
| VerfasserIn |
K. K. Khurana, M. K. Dougherty, C. T. Russell |
| Konferenz |
EGU General Assembly 2009
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 11 (2009) |
| Datensatznummer |
250022431
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| Zusammenfassung |
| In mid 2008, the Cassini spacecraft monitored the high latitude region (50∘-75∘)
of Saturn’s magnetosphere near its periapsis passes at radial distances of 3-6 RS.
The magnetometer onboard Cassini recorded strong perturbations in the azimuthal
component of the magnetic field during these passes suggesting passage of the spacecraft
through strong sheets of field-aligned currents (FACs). The invariant latitude of
the spacecraft was close to 70∘ and the local time was close to 00 hrs during the
passages through the FACs. A statistical analysis of these currents shows that they are
generated primarily by the global current circuit that enforces corotation on the
outflowing plasma. The direction of the current is always directed away from the
ionosphere and its strength is variable from pass to pass and is strongly ordered by the
period determined by the SKR amplitude variations. We show that the variability
of the FACs is caused by the superposition of two current systems, namely the
corotation enforcement current system and a rotating partial ring current system
which closes in the equatorial plane between the radial distances of 8 and 12 RS. |
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