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14Complex Systems of Charged Particles and their Interactions with Electromagnetic Radiation 2018
DUSTY PLASMAS IN THE SYSTEM OF MARTIAN SATELLITES
S.I. Popel, A.P. Golub', L.M. Zelenyi
Space Research Institute RAS, Moscow, Russia, e-mail: popel@iki.rssi.ru
The system of Mars is actively being studied with spacecrafts. Spacecrafts Mars Express, ExoMars Trace Gas Orbiter, etc., are operating successfully. The surface of Mars is being studied with Mars Exploration Rover Opportunity and Mars Science Laboratory Curiosity. The Phobos-Grunt 2 mission to the Martian satellite Phobos is under preparation. The study of Phobos and Deimos is of interest, in particular, because Phobos and Deimos are more accessible for manned missions than Mars in view of a weaker gravitational field. According to data from different space missions, the surfaces of Phobos and Deimos are covered by a dust consisting of uncoupled small regolith particles formed because of micrometeorite bombardment. Impacts of meteoroids on the surfaces of Phobos and Deimos play an important role in the formation of the dusty plasma systems near Martian moons. Secondary particles knocked out from the surfaces of Phobos and Deimos because of bombardment by meteoroids acquire a velocity exceeding the escape velocity (approximately equal to 10 m/s for Phobos and 6 m/s for Deimos,) and leave them. If the velocity of secondary particles is lower than the orbital velocity of the corresponding Martian satellite (2.1 km/s for Phobos and 1.35 km/s for Deimos), particles can appear in orbits around Mars. Finally, formation of a dust halo near the orbits of Phobos and Deimos is possible. Dusty plasmas are shown to be also formed in the surface layers over the illuminated part of Mars' satellites Phobos and Deimos owing to photoelectric and electrostatic processes. The distribution functions of photoelectrons near surfaces of the satellites, altitude dependences of the density of dust particles, and their charges and sizes, as well as electric fields are determined within a physical-mathematical model for the self-consistent description of densities of photoelectrons and dust particles over the surface of the illuminated parts of Phobos and Deimos. In view of a weak gravitational field, dust particles rising over the surfaces of Phobos and Deimos are larger than those over the surface of the Moon. In this case, the role of adhesion, which is a significant process preventing the separation of dust particles from the lunar surface, is much smaller on Phobos and Deimos.
This work was supported by the Russian Foundation for Basic Research (project no. 1802-00341) and by the Presidium of the Russian Academy of Sciences (program no. 28 "Space: Research of fundamental processes and their interrelations").
