2,1,3,- 1University of New Brunswick, Fredericton, Canada (karim@unb.ca)
- 2IRAP, Université de Toulouse, CNRS, UPS, CNES, Toulouse, France
- 3Institute of Physics/Lustbühel Observatory, University of Graz, Graz, Austria
- 4IAFE/CONICET, University of Buenos Aires, Ciudad Autónoma de Buenos Aires, Argentina
- 5Department of Physics and Astronomy, University of Iowa, Iowa City, IA, USA
- 6Space Sciences Laboratory, University of California, Berkeley, USA
- 7NASA Goddard Space Center, Greenbelt, Maryland, USA
- 8Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, USA
In the terrestrial foreshock, sunward propagating ion beam of several keV collimated along the interplanetary field lines (Field-Aligned Beams)
are usually observed within a region upstream from the quasi-perpendicular shock. Numerous observations indicate that these beams are not seen along IMF lines that make a angle larger than 70o with the local shock normal, thereby marking
the edge of the ion foreshock. The ion foreshock boundary reflects the maximum level of energization that solar wind ions can reach via coherent interaction with a planetary shock. In the present study, the Martian ion foreshock boundary
is investigated for the first time using MAVEN particle and magnetic field data. We found that no FAB is observed for a shock-θBn larger than 50o-55o. Our results indicate that the Martian ion foreshock boundary is located downstream of its terrestrial counterpart. This finding is in good agreement with
a recent report showing that FABs observed in the Martian foreshock have noticeably lower speeds than those observed at Earth.
How to cite: Meziane, K., Mazelle, C., Hamza, A., Simon-Wedlund, C., Bertucci, C., Halekas, J., Mitchell, D., Espley, J., and Curry, S.: An Ion Foreshock Boundary Upstream of the Martian Bow Shock, Europlanet Science Congress 2026, The Hague, The Netherlands, 7–11 Sep 2026, EPSC2026-1074, https://doi.org/10.5194/epsc2026-1074, 2026.
