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- Title
Alfvén Wave Propagation in the Io Plasma Torus.
- Authors
Hinton, P. C.; Bagenal, F.; Bonfond, B.
- Abstract
Io, the most volcanically active body in the solar system, fuels a plasma torus around Jupiter with dissociation products of SO2 at a rate of ~1,000 kg/s. We use a combination of in situ Voyager 1 data and Cassini Ultraviolet Imaging Spectrograph observations to constrain a diffusive equilibrium model of the Io plasma torus. The interaction of the Io plasma torus with Io launches Alfvén waves in both directions along magnetic field lines. We use the recent Juno‐based JRM09 magnetic field model combined with our 3‐D model of the Io plasma torus to simulate the propagation of Alfvén waves from the moon to the ionosphere of Jupiter. We map the location of multiple reflections of iogenic Alfvén waves between the northern and southern hemispheres. The location of the first few bounces of the Alfvén wave pattern match the Io auroral footprints observed by the Hubble Space Telescope. Plain Language Summary: Jupiter's moon Io is embedded in toroidal cloud of plasma that comes from the ionization of SO2 gas escaping from the volcanic moon. As Jupiter's magnetosphere rotates, it sweeps past Io in its orbit, disturbing the flow of the plasma torus. These disturbances travel along magnetic field lines, exciting electrons that stimulate aurora in Jupiter's atmosphere. We use a model of the plasma torus plus a model of Jupiter's magnetic field derived from recent measurements by the Juno spacecraft to predict the location of Io's auroral footprints. These predictions are compared with observations from the Hubble Space Telescope. Key Points: A 3‐D plasma torus model is combined with the JRM09 magnetic field model to produce updated Alfvén travel timesOne‐way Alfvén travel times range from ~2 to ~12 min when Io is below/above the torus at 20/200 degrees West System III longitudes, respectivelyThe Alfvén wing locations predicted by the model in Jupiter's ionosphere closely match the location of auroral emissions observed by Hubble Space Telescope
- Subjects
MAGNETIC fields; MAGNETOSPHERE; SOLAR wind; PLASMA gases; JUNO (Space probe)
- Publication
Geophysical Research Letters, 2019, Vol 46, Issue 3, p1242
- ISSN
0094-8276
- Publication type
Article
- DOI
10.1029/2018GL081472