The spatial distribution of planetary ion fluxes near Mars observed by MAVEN

David A. Brain (1) , J. P. Mcfadden (2) , Jasper S. Halekas (3) , J. E. P. Connerney (4) , Stephen W. Bougher (5) , Shannon Curry (2) , C. F. Dong (5) , Y. Dong (1) , F. Eparvier (1) , Xiaohua Fang (1) , K. Fortier (1) , T. Hara (2) , Y. Harada (2) , Bruce M. Jakosky (1) , Robert J. Lillis (2) , R. Livi (2) , Janet G. Luhmann (2) , Yingjuan Ma (6) , Ronan Modolo (7) , Kanako Seki (8)

1 LASP - Laboratory for Atmospheric and Space Physics [Boulder]
2 SSL - Space Sciences Laboratory [Berkeley]
3 Department of Physics and Astronomy [Ames, Iowa]
4 GSFC - NASA Goddard Space Flight Center
5 AOSS - Department of Atmospheric, Oceanic, and Space Sciences [Ann Arbor]
6 IGPP - Institute of Geophysics and Planetary Physics [Los Angeles]
7 HELIOS - LATMOS
8 STEL - Solar-Terrestrial Environment Laboratory [Nagoya]

We present the results of an initial effort to statistically map the fluxes of planetary ions on a closed surface around Mars. Choosing a spherical shell ~1000 km above the planet, we map both outgoing and incoming ion fluxes (with energies >25 eV) over a 4 month period. The results show net escape of planetary ions behind Mars and strong fluxes of escaping ions from the northern hemisphere with respect to the solar wind convection electric field. Planetary ions also travel toward the planet, and return fluxes are particularly strong in the southern electric field hemisphere. We obtain a lower bound estimate for planetary ion escape of ~3 × 1024 s−1, accounting for the ~10% of ions that return toward the planet and assuming that the ~70% of the surface covered so far is representative of the regions not yet visited by Mars Atmosphere and Volatile EvolutioN (MAVEN).

Mots clés: atmospheric escape; solar wind interaction

Domaines: Planétologie et astrophysique de la terre [astro-ph.EP]; Astrophysique stellaire et solaire [astro-ph.SR]

David A. Brain, J. P. Mcfadden, Jasper S. Halekas, J. E. P. Connerney, Stephen W. Bougher, et al.. The spatial distribution of planetary ion fluxes near Mars observed by MAVEN. Geophysical Research Letters, 2015, 42 (21), pp.9142-9148. ⟨10.1002/2015GL065293⟩. ⟨insu-01238375⟩