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Detailed Reference Information |
Neubauer, F.M. (1999). Alfvén wings and electromagnetic induction in the interiors: Europa and Callisto. Journal of Geophysical Research 104: doi: 10.1029/1999JA900217. issn: 0148-0227. |
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The recent evidence for the importance of magnetic fields due to electromagnetic induction in the conducting interiors of the satellites Europa and Callisto has motivated this extension of the Alfv¿n wing model to include induction effects. These are due to the temporal variations of the Jovian magnetospheric field at the satellite positions. We show that the maximum strength of the induction effects in a satellite during a Jovian synodic rotation increases as a function of distance from Jupiter because of the increasing significance of the current sheet. For the modified Alfv¿n wings we obtain the following results which also order the recent Galileo results: (1) For very small Alfv¿n Mach numbers the maximum Alfv¿n wing currents are reduced by the induction effects. This behavior is favored by a small distance between the conducting satellite interior and outer ionospheric boundary. (2) During a Jovian synodic rotation past a satellite the Alfv¿n wings are strongest at crossings of the central current sheet, whereas induction magnetic fields are most significant at maximum magnetic latitude. This result may be important for satellite footprint observations. (3) The maximum Alfv¿n wing current in item 1 also applies for somewhat larger Alfv¿n Mach numbers, if the ionospheric conductivity distribution is symmetric between the upstreamside and the downstreamside. For a dominating conductivity on the downstreamside the maximum Alfv¿n wing current is enhanced and vice versa for the opposite conductivity distribution. (4) Magnetic field measurements from satellite orbiters can be used to probe their conducting interiors, for examples any salty oceans. ¿ 1999 American Geophysical Union |
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Abstract |
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Keywords
Electromagnetics, Electromagnetic theory, Geomagnetism and Paleomagnetism, Geomagnetic induction, Magnetospheric Physics, Magnetosphere interactions with satellites and rings, Planetology, Solar System Objects, Jovian satellites, Interplanetary Physics, Interplanetary shocks, Magnetospheric Physics, Magnetosphere/ionosphere interactions |
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Publisher
American Geophysical Union 2000 Florida Avenue N.W. Washington, D.C. 20009-1277 USA 1-202-462-6900 1-202-328-0566 service@agu.org |
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