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| Titel |
Axi-symmetric models of auroral current systems in Jupiter's magnetosphere with predictions for the Juno mission |
| VerfasserIn |
S. W. H. Cowley, A. J. Deason, E. J. Bunce |
| 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. 12 ; Nr. 26, no. 12 (2008-12-12), S.4051-4074 |
| Datensatznummer |
250016330
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| Publikation (Nr.) |
 copernicus.org/angeo-26-4051-2008.pdf |
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| Zusammenfassung |
| We develop two related models of magnetosphere-ionosphere
coupling in the jovian system by combining previous models defined at
ionospheric heights with magnetospheric magnetic models that allow system
parameters to be extended appropriately into the magnetosphere. The key
feature of the combined models is thus that they allow direct connection to
be made between observations in the magnetosphere, particularly of the
azimuthal field produced by the magnetosphere-ionosphere coupling currents
and the plasma angular velocity, and the auroral response in the ionosphere.
The two models are intended to reflect typical steady-state sub-corotation
conditions in the jovian magnetosphere, and transient super-corotation
produced by sudden major solar wind-induced compressions, respectively. The
key simplification of the models is that of axi-symmetry of the field, flow,
and currents about the magnetic axis, limiting their validity to radial
distances within ~30 RJ of the planet, though the magnetic axis
is appropriately tilted relative to the planetary spin axis and rotates with
the planet. The first exploration of the jovian polar magnetosphere is
planned to be undertaken in 2016–2017 during the NASA New Frontiers Juno
mission, with observations of the polar field, plasma, and UV emissions as a
major goal. Evaluation of the models along Juno planning orbits thus
produces predictive results that may aid in science mission planning. It is
shown in particular that the low-altitude near-periapsis polar passes will
generally occur underneath the corresponding auroral acceleration regions,
thus allowing brief examination of the auroral primaries over intervals of
~1–3 min for the main oval and ~10 s for narrower polar
arc structures, while the "lagging" field deflections produced by the
auroral current systems on these passes will be ~0.1°, associated
with azimuthal fields above the ionosphere of a few hundred nT. |
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