Revisiting Discrete Energy Bands in Galilean Moon's Footprint Tails: Remote Signals of Particle Absorption
Abstract Observations from the Juno spacecraft near the M‐shells of the Galilean moons have identified alternating enhancements and reductions of particle fluxes at discrete energies. These banded structures were previously attributed to bounce resonance between particles and standing Alfvén waves generated by moon‐magnetospheric interactions. Here, we show that this explanation is inconsistent with key observational features, and propose an alternative interpretation: the bands are remote signatures of particle absorption at the moons. In this scenario, whether a particle encounters the moon before reaching Juno depends on the number of bounce cycles it undergoes within a fixed drift segment determined by the moon‐spacecraft separation. Therefore, the absorption bands are expected to appear at discrete, equally‐spaced velocities. This is largely consistent with the observations, though discrepancies remain, possibly due to spacecraft charging and/or finite data resolution. This finding improves our understanding of moon‐plasma interactions and may help constrain Jovian magnetospheric models.
Authors
- Michel Blanc (ORCID: https://orcid.org/0000-0002-1290-7350)
- Chao Yue (ORCID: https://orcid.org/0000-0001-9720-5210)
- Xu‐Zhi Zhou (ORCID: https://orcid.org/0000-0003-4953-1761)
- Yixin Hao (ORCID: https://orcid.org/0000-0003-0425-3358)
- Qiugang Zong (ORCID: https://orcid.org/0000-0002-6414-3794)
- Zhi‐Yang Liu (ORCID: https://orcid.org/0000-0003-3800-1044)
- Ying Liu (ORCID: https://orcid.org/0000-0002-1674-849X)
- Jiutong Zhao (ORCID: https://orcid.org/0000-0003-0263-4878)
- Yixin Sun (ORCID: https://orcid.org/0000-0003-3568-4839)
- Ze‐Fan Yin (ORCID: https://orcid.org/0000-0001-7341-5467)
- Da He (ORCID: https://orcid.org/0000-0002-7998-1045)
- Shan Wang (ORCID: https://orcid.org/0000-0002-6783-7759)
- F. Yang (ORCID: https://orcid.org/0000-0001-7591-1093)
- Ya‐Ze Wu
Institutions
- Macau University of Science and Technology (MO)
- Centre National de la Recherche Scientifique (FR)
- Université Toulouse III - Paul Sabatier (FR)
- Peking University (CN)
- Max Planck Institute for Solar System Research (DE)
- Institut de Recherche en Astrophysique et Planétologie (FR)
- University of California, Berkeley (US)
Publication Details
- Journal
- Geophysical Research Letters
- Published
- 2025-07-21
- DOI
- https://doi.org/10.1029/2024gl112240
- Citations
- 1
- Primary Topic
- Solar and Space Plasma Dynamics
- Type
- article
- Field-Weighted Citation Impact
- 1.15
Funders
- National Natural Science Foundation of China