Journal article
Juno Observations of Io's Alfvén Wing From 23 Io Radii
Geophysical research letters, Vol.52(13), e2025GL115497
07/16/2025
DOI: 10.1029/2025GL115497
Appears in UI Libraries Support Open Access
Abstract
On 13 June, day 165 of 2024, Juno passed through Io's main Alfvén wing at a distance of ∼23 Io radii south of the moon during perijove 62. Evidence for this passage was clearly seen in the Juno plasma wave, magnetometer, and plasma data. The plasma wave signature was an intensification of quasi‐electrostatic waves below about 1 kHz with a weaker magnetic component, all lasting for about two minutes. A strong perturbation of the magnetic field consistent with strong field‐aligned currents was observed at the edges of the Alfvén wing. Ions in the range below about 1 keV/q were slowed within the Alfvén wing. As with other measurements in Io's Alfvén wing, we observe evidence of filamentation. The power in the Alfvén wing based on the measured Poynting flux is estimated to be ∼500–1,500 × 10 9 W.
This paper takes advantage of a chance crossing of Jupiter's magnetic field disturbed by Io's strong electromagnetic interaction to study how Io affects Jupiter's environment. These Juno observations are from a distance intermediate between the two close encounters of Io on previous orbits and much more distant observations above Jupiter's ionosphere. The plasma wave spectrum is very similar to that observed close to Io. Additionally, ions moving around Jupiter are slowed down by the interaction. This interaction is called an Alfvén wing that carries about 18 million Amps and transmits about 500 billion Watts from Io to Jupiter's ionosphere, causing a bright auroral spot on Jupiter.
Juno plasma wave, magnetic field, and ion data provide evidence of a main Alfvén wing crossing about 23 R I below Io on perijove 62 This Alfvén wing crossing is at an intermediate distance between close flybys and crossings near Jupiter's ionosphere The temporal variability of the plasma waves is consistent with filamented Alfvén waves
Details
- Title: Subtitle
- Juno Observations of Io's Alfvén Wing From 23 Io Radii
- Creators
- W. S. Kurth - University of IowaA. H. Sulaiman - University of MinnesotaJ. E. P. Connerney - Goddard Space Flight CenterF. Allegrini - Southwest Research InstituteP. Valek - Southwest Research InstituteR. W. Ebert - Southwest Research InstituteC. Paranicas - Allentown Public LibraryG. B. Clark - Allentown Public LibraryN. Kruegler - University of MinnesotaG. B. Hospodarsky - University of IowaC. W. Piker - University of IowaS. Kotsiaros - European Space Astronomy CentreM. Imai - Czech Academy of Sciences, Institute of Atmospheric PhysicsS. J. Bolton - Southwest Research Institute
- Resource Type
- Journal article
- Publication Details
- Geophysical research letters, Vol.52(13), e2025GL115497
- DOI
- 10.1029/2025GL115497
- ISSN
- 0094-8276
- eISSN
- 1944-8007
- Publisher
- Wiley
- Grant note
- Southwest Research Institute: 80NSSC24K1837 NASA: NNM06AA75C, LQ100422501 NASA's New Frontiers Program for JunoCzech Academy of SciencesRoy J. Carver Charitable Trust
The research at the University of Iowa is supported by NASA through Contract 699041X with the Southwest Research Institute. The research at the University of Minnesota is partly supported by NASA through contract S99022AKP with the Southwest Research Institute. NK and AHS acknowledge NASA Grant 80NSSC24K1837. The work at Southwest Research Institute is funded by NASA's New Frontiers Program for Juno through contract NNM06AA75C. The work of MI is supported by the Lumina Quaeruntur fellowship (LQ100422501) of the Czech Academy of Sciences. WSK acknowledges the use of the Space Physics Data Repository at the University of Iowa supported by the Roy J. Carver Charitable Trust.
- Language
- English
- Date published
- 07/16/2025
- Academic Unit
- Physics and Astronomy
- Record Identifier
- 9984843585302771
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