Nonstationary Processes in the Formation of a Dusty Plasma near the Surface of Phobos

The formation of a dusty plasma in photoelectric and electrostatic processes in the near-surface layer over the illuminated part of the moon of Mars Phobos is discussed. The parameters characterizing trajectories of dust particles have been determined within a physicomathematical model for the self-consistent description of densities of photoelectrons and dust particles over the illuminated part of the surface of Phobos. It has been shown that the damping of oscillations of a dust particle over the surface of Phobos is related to variations of its charge in agreement with concepts of anomalous dissipation caused by processes associated with variation of charges of dust particles. It has been demonstrated that the damping time of their oscillations for most of the dust particles rising over the surface of Phobos because of photoelectric and electrostatic processes is longer than the daytime; i.e., the nonstationarity of the dusty plasma system over the illuminated part of the surface of Phobos is manifested during almost the entire day on it. The maximum rising altitude and charge that can be reached by dust particles with different sizes have been determined. The typical densities of dust particles and photoelectrons over Phobos have been estimated. To obtain more definite data on the parameters of the dusty plasma system near Phobos, more detailed information on the properties of its soil is necessary; it is expected that this information will be obtained in future space missions.