Open AccessBackscattered solar wind protons by Phobos
Author(s) -
Futaana Y.,
Barabash S.,
Holmström M.,
Fedorov A.,
Nilsson H.,
Lundin R.,
Dubinin E.,
Fränz M.
Publication year - 2010
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2010ja015486
Subject(s) - regolith , solar wind , mars exploration program , physics , magnetopause , astrobiology , polar wind , geophysics , coronal mass ejection , astronomy , plasma , nuclear physics
We report Mars Express (MEX) measurements showing that the regolith‐covered Phobos surface backscatters 0.5%–10% of the impinging solar wind protons. Backscattered protons with an energy corresponding to 30%–40% of the solar wind energy injected in the flow are picked up by the solar wind and may cause field disturbances and wave activity. Since a similar backscattering of solar wind protons was observed and reported at the Moon, the backscattering of the solar wind particles is a typical physical process for regolith‐covered bodies in space, even though the regolith is highly porous and it has been thought that almost 100% of the solar wind protons are implanted.