Journal article
Whistler‐Mode Waves and Associated Electron Distributions in Jupiter's Middle and Outer Magnetosphere
Geophysical research letters, Vol.52(18), e2025GL116543
09/28/2025
DOI: 10.1029/2025GL116543
Abstract
Whistler‐mode waves play a crucial role in shaping magnetospheric electron dynamics. Using Juno's observations, we investigate these waves in Jupiter's post‐midnight‐to‐dawn magnetosphere, spanning 20–80 Jupiter radii. Our survey reveals that whistler‐mode waves predominantly occur in the lobes, while the magnetodisk remains largely devoid of such waves. Simultaneous electron measurements from JADE‐E, combined with dispersion relation analysis, indicate that these waves are likely driven by a mono‐directional electron population between ∼ ${\sim} $0.1 and 10 keV propagating anti‐Jupiter‐ward. Further controlled studies show that a local flux minimum at ∼ ${\sim} $0.3 keV in the electron energy spectrum, which is commonly detected during whistler‐mode waves, is critical for wave growth. Based on their direction of motion, we suggest that these mono‐directional electrons and the whistler‐mode waves they generate are related to magnetosphere‐ionosphere coupling. Our findings offer new insights into the interplay between whistler‐mode waves and electrons in Jupiter's magnetosphere.
Plain Language Summary
Whistler‐mode waves are a wave mode in plasma occurring near and below the electron cyclotron frequency. They are commonly observed in planetary magnetospheres and play a crucial role in the acceleration and precipitation of magnetospheric electrons. Using data from NASA's Juno spacecraft, we investigate whistler‐mode waves in Jupiter's magnetosphere, focusing on the region between 20 and 80 Jupiter radii on the post‐midnight‐to‐dawn side. Our findings show that these waves primarily occur in the lobes, where the magnetic field is strong and plasma density is low, rather than in the central magnetodisk, where the field is weaker and plasma is denser. Analysis of electron distributions during these wave events reveals that a 0.1–10 keV population traveling anti‐Jupiter‐ward along the magnetic field may serve as the free energy source for these waves. Given their motion, these electrons might be linked to magnetosphere‐ionosphere coupling. Our results enhance our understanding of whistler‐mode waves and associated electron dynamics in Jupiter's magnetosphere.
Key Points
Whistler‐mode waves mainly occur in the lobes rather than in the magnetodisk in Jupiter's post‐midnight, middle to outer magnetosphere
These waves are likely driven by an anti‐Jupiter‐ward, mono‐directional electron population between 0.1 and 1 keV
Electron energy spectra observed during these waves exhibit a local flux minimum at 0.3 keV, which plays a crucial role in wave growth
Details
- Title: Subtitle
- Whistler‐Mode Waves and Associated Electron Distributions in Jupiter's Middle and Outer Magnetosphere
- Creators
- Z.‐Y. Liu - CNES‐CNRS‐Université Toulouse III Paul SabatierN. André - Université Toulouse III - Paul SabatierM. Blanc - Université Toulouse III - Paul SabatierL. Li - China University of Geosciences (Beijing)J Rabia - Centre National de la Recherche ScientifiqueF. Allegrini - Southwest Research InstituteR. W. Ebert - Southwest Research InstituteW. S. Kurth - University of IowaJ. E. P. Connerney - Goddard Space Flight CenterS. Bolton - Southwest Research Institute
- Resource Type
- Journal article
- Publication Details
- Geophysical research letters, Vol.52(18), e2025GL116543
- DOI
- 10.1029/2025GL116543
- ISSN
- 0094-8276
- eISSN
- 1944-8007
- Publisher
- Wiley
- Number of pages
- 10
- Grant note
- NASA NFDAP (80NSSC23K0658) Centre National d'Etudes Spatiales Centre National de la Recherche Scientifique NASA's New Frontiers Program for Juno (NNM06AA75C)
- Language
- English
- Date published
- 09/28/2025
- Academic Unit
- Physics and Astronomy
- Record Identifier
- 9984966339502771
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