Field‐Aligned Proton Beams Upstream of the Martian Bow Shock: First Observations
Abstract We report fast sunward‐propagating energetic proton field‐aligned beams (FABs) observed about one Mars radius upstream of the Martian bow shock, recorded by the Solar Wind Ion Analyzer instrument on the MAVEN spacecraft. The velocity distributions show that all the beams have a bulk parallel speed , exceeding the shock speed . Several FABs are observed in the field‐aligned region, linked to the quasi‐parallel shock. The nearly synchronous variations of shock values and beam speeds rule out specular reflection, suggesting a non‐specular reflection mechanism. However, the slower Martian foreshock beam speeds remain unexplained compared to their terrestrial counterparts.
Authors
- D. L. Mitchell (ORCID: https://orcid.org/0000-0001-9154-7236)
- J. S. Halekas (ORCID: https://orcid.org/0000-0001-5258-6128)
- C. Bertucci (ORCID: https://orcid.org/0000-0002-2540-5384)
- J. R. Espley (ORCID: https://orcid.org/0000-0002-6371-9683)
- K. Meziane (ORCID: https://orcid.org/0000-0002-2527-9816)
- A. M. Hamza (ORCID: https://orcid.org/0000-0002-2556-5994)
- C. Mazelle (ORCID: https://orcid.org/0000-0001-5332-9561)
Institutions
- University of New Brunswick (CA)
- University of Iowa (US)
- Centre National de la Recherche Scientifique (FR)
- Goddard Space Flight Center (US)
- Université Toulouse III - Paul Sabatier (FR)
- Austrian Academy of Sciences (AT)
- Université Fédérale de Toulouse Midi-Pyrénées (FR)
- Space Research Institute (AT)
- Institute of Astronomy and Space Physics (AR)
- University of California, Berkeley (US)
Publication Details
- Journal
- Geophysical Research Letters
- Published
- 2025-05-30
- DOI
- https://doi.org/10.1029/2025gl115483
- Citations
- 1
- Primary Topic
- Planetary Science and Exploration
- Type
- article
- Field-Weighted Citation Impact
- 1.15
Funders
- Centre National d’Etudes Spatiales