Evidence of an Extended Alfvén Wing System at Enceladus: Cassini's Multi‐Instrument Observations
Year: 2026
Type: article
Abstract: We report in situ evidence for Enceladus' Alfvén wing system and its coupling with Saturn's ionosphere, based on multi‐instrument observations from the Cassini spacecraft. Analysis of 36 events, including 13 from non‐flyby paths, confirms the existence of a Main Alfvén Wing (MAW) current system generated at Enceladus, and associated Reflected Alfvén Wings (RAWs) occurring both at Saturn's ionosphere and on the density gradient of Enceladus' plasma torus, extending longitudinally to at least (2,000 moon radii) downstream of the moon. Additionally, the observations reveal the systematic existence of a filamentation process of these large‐scale Alfvénic perturbations (MAW and RAWs) during their propagation at any distance from their source. These findings demonstrate a more extensive electrodynamic coupling than previously reported for Enceladus and more generally for any moon‐magnetosphere interaction. Moreover, the observation of energetic electron depletions and water‐group ion signatures at longitudes even further from the moon supports the interpretation of an extended and persistent interaction region. These results highlight Enceladus' role in shaping Saturn's magnetospheric environment and underscore the importance of future missions to exhaustively analyze this type of complex interaction between a moon and a planet.
DOI: 10.1029/2025ja034657
Authors: L. Z. Hadid, T. Chust, J.‐E. Wahlund, M. W. Morooka, E. Roussos, O. Witasse, J. Rabia, D. Pisa, K. Kim, N. J. T. Edberg, A. M. Rymer, L. Lamy, S. Kotsiaros, S. Aizawa, A. Jeandet, R. Modolo, N. André, P. Canu, C. F. Bowers, X. Jia, A. J. Coates, G. H. Jones, A. Parsec‐Wallis, O. Agiwal, M. K. G. Holmberg, Q. Nénon, H. Cao, W. S. Kurth, M. K. Dougherty
Institutions: Centre National de la Recherche Scientifique, École Polytechnique, Université Paris-Saclay, Observatoire de Paris, Sorbonne Université, Institut Polytechnique de Paris, Laboratoire de Physique des Plasmas, Swedish Institute of Space Physics, Max Planck Institute for Solar System Research, European Space Agency, European Space Research and Technology Centre, Université Toulouse III - Paul Sabatier, Institut de Recherche en Astrophysique et Planétologie, Czech Academy of Sciences, Czech Academy of Sciences, Institute of Atmospheric Physics, Uppsala University, Johns Hopkins University, Johns Hopkins University Applied Physics Laboratory, Université Paris Cité, Aix-Marseille Université, Université Paris Sciences et Lettres, LIRA - Laboratoire d'instrumentation et de recherche en astrophysique, European Space Astronomy Centre, Université de Versailles Saint-Quentin-en-Yvelines, Institut Pierre-Simon Laplace, Laboratoire atmosphères, milieux, observations spatiales, Institut Supérieur de l'Aéronautique et de l'Espace (ISAE-SUPAERO), ISAE-SUPAERO Recherche, University of Michigan, University College London, Birkbeck, University of London, Boston University, Dublin Institute For Advanced Studies, University of California, Los Angeles, University of Iowa, Imperial College London
Language: English
Subfield: Astronomy and Astrophysics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $4,070
OpenAlex ID: W7128426887