A source of very energetic oxygen located in Jupiter's inner radiation belts
Abstract
Jupiter hosts the most hazardous radiation belts of our solar system that, besides electrons and protons, trap an undetermined mix of heavy ions. The details of this mix are critical to resolve because they can reveal the role of Jupiter's moons relative to other less explored energetic ion sources. Here, we show that with increasing energy and in the vicinity of Jupiter's moon Amalthea, the belts' ion composition transitions from sulfur- to oxygen-dominated due to a local source of ≳50 MeV/nucleon oxygen. Contrary to Earth's and Saturn's radiation belts, where their most energetic ions are supplied through atmospheric and ring interactions with externally accelerated cosmic rays, Jupiter's magnetosphere powers this oxygen source internally. The underlying source mechanism, involving either Jovian ring spallation by magnetospheric sulfur or stochastic oxygen heating by low-frequency plasma waves, puts Jupiter's ion radiation belt in the same league with that of astrophysical particle accelerators.
Additional Information
© 2022 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works. Distributed under a Creative Commons Attribution NonCommercial License 4.0 (CC BY-NC). Submitted 17 September 2021; Accepted 19 November 2021; Published 12 January 2022. We acknowledge support by the PDS through which the HIC data were obtained and R. Wilson (LASP, USA) and R. Selesnick (Air Force Research Laboratory, USA) for assistance in reconstructing the HIC pointing. We are thankful to the GEANT4 collaboration and J. F. Ziegler for making available the GEANT4 and SRIM packages that were used to simulate HIC responses and ring spallation. E.R. and N.K. are supported by the German Space Agency (DLR) through contract 50 QJ 1503 and by the Max Planck Society. Author contributions: All authors contributed to the discussion and interpretation of the data and the writing of the manuscript. E.R. developed the study concept and performed most data analysis tasks, including simulations of the HIC sensor responses. C.C. contributed to the evaluation and interpretation of the PDS-archived data of HIC. P.K. provided software for the range-energy analysis of HIC responses, generated the processed EPD/CMS data, and performed the magnetic mapping of Galileo measurements. M.P. performed GEANT4 simulations of ring spallation. K.D. contributed to the analysis of HIC and EPD spectra. N.K. and P.G. administered the project on the side of MPS and LIP, respectively. The authors declare that they have no competing interests. Data and materials availability: All HIC data used in the present study are available through NASA's PDS at https://pds-ppi.igpp.ucla.edu/search/?sc=Galileo&t=Jupiter&i=HIC. Processed Galileo EPD/CMS data are available at sd-www.jhuapl.edu/Galileo_EPD/. The processing steps of these datasets and caveats of the archived datasets are described in Materials and Methods.Attached Files
Published - sciadv.abm4234.pdf
Supplemental Material - sciadv.abm4234_sm.pdf
Files
| Name | Size | Download all |
|---|---|---|
|
md5:cd55a39c47c4fd7193ea45bcda2ddfd0
|
1.4 MB | Preview Download |
|
md5:5815077b88a89907ed438626ae8ab622
|
5.0 MB | Preview Download |
Additional details
- Eprint ID
- 112849
- Resolver ID
- CaltechAUTHORS:20220112-204842129
- 50 QJ 1503
- Deutsches Zentrum für Luft- und Raumfahrt (DLR)
- Max Planck Society
- Created
-
2022-01-12Created from EPrint's datestamp field
- Updated
-
2022-01-12Created from EPrint's last_modified field
- Caltech groups
- Space Radiation Laboratory