Radial Evolution of Electron Pitch Angle Distributions in the Inner Part of Jovian Magnetosphere
Abstract Previous observations in Jupiter's magnetosphere have revealed that the pitch‐angle distributions (PADs) of energetic ( keV) electrons transition from pancake to field‐aligned distributions from 10 to 20 Jupiter radii. Here, by analyzing Juno/JADE‐E data, we show that a similar transition also occurs for electrons at energy keV. This feature is persistent, observed over a span of 6 years and across all nightside local times. Further analysis reveals that the transition occurs at larger M‐shells for higher‐energy electrons and at greater distances from the equatorial plane, placing strong constraints on the underlying mechanisms. By developing a model based on Liouville's theorem and the conservation of adiabatic invariants, we show that adiabatic radial transport can reproduce these features, suggesting it as a mechanism driving the observed PAD transition. However, the noted discrepancies in absolute flux between observations and the modeling results suggest non‐adiabatic effects may still play a role in electron dynamics.
Authors
- F. Allegrini (ORCID: https://orcid.org/0000-0003-0696-4380)
- Michel Blanc (ORCID: https://orcid.org/0000-0002-1290-7350)
- Y. Sarkango (ORCID: https://orcid.org/0000-0001-7812-7464)
- Zhi‐Yang Liu (ORCID: https://orcid.org/0000-0003-3800-1044)
- J. E. P. Connerney (ORCID: https://orcid.org/0000-0001-7478-6462)
- R. W. Ebert (ORCID: https://orcid.org/0000-0002-2504-4320)
- J. Rabia (ORCID: https://orcid.org/0000-0003-1429-9122)
- S. J. Bolton (ORCID: https://orcid.org/0000-0002-9115-0789)
- Nicolás André (ORCID: https://orcid.org/0000-0001-8017-5676)
- J. R. Szalay (ORCID: https://orcid.org/0000-0003-2685-9801)
Institutions
- Southwest Research Institute (US)
- Centre National de la Recherche Scientifique (FR)
- Goddard Space Flight Center (US)
- Université Toulouse III - Paul Sabatier (FR)
- Université Fédérale de Toulouse Midi-Pyrénées (FR)
- Institut Superieur de l'Aeronautique et de l'Espace (ISAE-SUPAERO) (FR)
- Princeton University (US)
- Aix-Marseille Université (FR)
- Laboratoire d’Astrophysique de Marseille (FR)
- Institut de Recherche en Astrophysique et Planétologie (FR)
- The University of Texas at San Antonio (US)
Publication Details
- Journal
- Geophysical Research Letters
- Published
- 2025-09-09
- DOI
- https://doi.org/10.1029/2025gl114751
- Citations
- 1
- Primary Topic
- Astro and Planetary Science
- Type
- article
- Field-Weighted Citation Impact
- 1.15
Funders
- National Aeronautics and Space Administration