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Axi-symmetric models of auroral current systems in Jupiter's magnetosphere with predictions for the Juno mission
journal contribution
posted on 2016-10-31, 16:48 authored by S. W. H. Cowley, A. J. Deason, E. J. BunceWe 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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Citation
Annales Geophysicae, 2008, 26 (12), pp. 4051-4074 (24)Author affiliation
/Organisation/COLLEGE OF SCIENCE AND ENGINEERING/Department of Physics and AstronomyVersion
- VoR (Version of Record)
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Annales GeophysicaePublisher
European Geosciences Union (EGU), Copernicus Publications, Springer Verlagissn
0992-7689eissn
1432-0576Copyright date
2008Available date
2016-10-31Publisher DOI
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http://www.ann-geophys.net/26/4051/2008/Language
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Science & TechnologyPhysical SciencesAstronomy & AstrophysicsGeosciences, MultidisciplinaryMeteorology & Atmospheric SciencesGeologyASTRONOMY & ASTROPHYSICSGEOSCIENCES, MULTIDISCIPLINARYMETEOROLOGY & ATMOSPHERIC SCIENCESMagnetospheric physicsAuroral phenomenaMagnetosphere-ionosphere interactionsPlanetary magnetospheresIONOSPHERIC PEDERSEN CONDUCTIVITYWIND-INDUCED COMPRESSIONSSOLAR-WINDMIDDLE MAGNETOSPHERECURRENT SHEETSPECTRAL OBSERVATIONSJOVIAN IONOSPHERECOUPLING CURRENTSEQUATORIAL PLANESTEADY-STATE
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