Mars' Ionospheric Interaction With Comet C/2013 A1 Siding Spring's Coma at Their Closest Approach as Seen by Mars Express

Beatriz Sánchez–cano (1) , Mark Lester (1) , Olivier Witasse (2) , David D. Morgan (3) , Hermann Opgenoorth (1, 4) , David J. Andrews (5) , Pierre‐louis Blelly (6) , Stanley W.H. Cowley (1) , Andy Kopf (3) , François Leblanc (7) , Jared R. Espley (8) , Alejandro Cardesín‐moinelo (9)

1 RSPP - Radio and Space Plasma Physics Group [Leicester]
2 ESTEC - European Space Research and Technology Centre
3 Department of Physics and Astronomy [Iowa City]
4 Department of Physics [Umeå]
5 IRF - Swedish Institute of Space Physics [Uppsala / Kiruna]
6 IRAP - Institut de recherche en astrophysique et planétologie
7 HELIOS - LATMOS
8 GSFC - NASA Goddard Space Flight Center
9 ESAC - European Space Astronomy Centre

On 19 October 2014, Mars experienced a close encounter with Comet C/2013 A1 Siding Spring. Using data from the Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS) on board Mars Express (MEX), we assess the interaction of the Martian ionosphere with the comet's coma and possibly magnetic tail during the orbit of their closest approach. The topside ionospheric electron density profile is evaluated from the altitude of the peak density of the ionosphere up to the Mars Express altitude. We find complex and rapid variability in the ionospheric profile along the MEX orbit, not seen even after the impact of a large coronal mass ejection. Before closest approach, large electron density reductions predominate, which could be caused either by comet water‐damping, or comet magnetic field interactions. After closest approach, a substantial electron density rise predominates. Moreover, several extra topside layers are visible along the whole orbit at different altitudes, which could be related to different processes as we discuss.

Domaines: Physique de l'espace [physics.space-ph]; Physique Atmosphérique et Océanique [physics.ao-ph]

Beatriz Sánchez–cano, Mark Lester, Olivier Witasse, David D. Morgan, Hermann Opgenoorth, et al.. Mars' Ionospheric Interaction With Comet C/2013 A1 Siding Spring's Coma at Their Closest Approach as Seen by Mars Express. Journal of Geophysical Research Space Physics, 2020, 125 (1), pp.e2019JA027344. ⟨10.1029/2019JA027344⟩. ⟨insu-02425019⟩