Solar Orbiter in Venus' Ionosphere: Observations From the 4th Flyby
Abstract Solar Orbiter entered the topside ionosphere of Venus for the first time when performing its 4th flyby of the planet, reaching an altitude of 378 km on 18 Feb 2025. High‐cadence electron density measurements showed previously unresolved fine‐structuring within plasma regions and boundaries, particularly at the ionopause. During the rapid flyby, a rare snapshot of the entire induced magnetosphere was captured during calm solar wind conditions around solar maximum. A well‐structured and a relatively steady plasma environment was observed. Assuming an electron temperature of 0.5 eV, pressure balance was found across the ionopause, while at the same time quasi‐periodic density and magnetic field variations suggest boundary oscillations. Near closest approach, non‐force free magnetic flux ropes were observed. Small‐scale perturbations in both magnetic field strength and density across them indicate them being dynamically evolving, rather than in a stationary state.
Authors
- Konstantin Kim (ORCID: https://orcid.org/0000-0002-1377-6401)
- David Píša (ORCID: https://orcid.org/0000-0002-1322-7576)
- M. Kretzschmar (ORCID: https://orcid.org/0000-0001-5796-6138)
- Marina I. F. Galand
- Jordi Boldu
- Thomas Chust (ORCID: https://orcid.org/0000-0002-2078-5824)
- David J. Andrews (ORCID: https://orcid.org/0000-0002-7933-0322)
- Antonio Vecchio (ORCID: https://orcid.org/0000-0002-2002-1701)
- Chris J. Owen (ORCID: https://orcid.org/0000-0002-5982-4667)
- Moa Persson (ORCID: https://orcid.org/0000-0003-3497-3209)
- Yuri V. Khotyaintsev (ORCID: https://orcid.org/0000-0001-5550-3113)
- Jan Souček (ORCID: https://orcid.org/0000-0003-0462-6804)
- Anders I. Eriksson (ORCID: https://orcid.org/0000-0003-2926-6761)
- Niklas J. T. Edberg (ORCID: https://orcid.org/0000-0002-1261-7580)
- Lina Z. Hadid
- Lorenzo Matteini
- Stuart D. Bale (ORCID: https://orcid.org/0000-0002-1989-3596)
- Milan Maksimovic
- Timothy S. Horbury
Institutions
- Uppsala University (SE)
- Université d'Orléans (FR)
- Centre National de la Recherche Scientifique (FR)
- Swedish Institute of Space Physics (SE)
- École Polytechnique (FR)
- Radboud University Nijmegen (NL)
- Université Paris Sciences et Lettres (FR)
- Sorbonne Université (FR)
- Czech Academy of Sciences, Institute of Atmospheric Physics (CZ)
- Laboratoire de Physique des Plasmas (FR)
- University College London (GB)
- Imperial College London (GB)
- University of California, Berkeley (US)
Publication Details
- Journal
- Journal of Geophysical Research Space Physics
- Published
- 2026-04-30
- DOI
- https://doi.org/10.1029/2025ja034813
- Primary Topic
- Planetary Science and Exploration
- Type
- article
- Field-Weighted Citation Impact
- 0.00