Plasma-Dust Processes in the Vicinity of Comets

A description of plasma–dust processes in the vicinity of comets is given. It has been shown that they can manifest themselves in situations where the comet is quite far from the Sun. In addition, plasma–dust processes can have a significant impact on the formation of the bow shock wave as a result of the interaction of the comet’s coma with the solar wind. It has been demonstrated that for a comet with nucleus parameters close to those of Halley’s comet, dusty plasma in the vicinity of the nucleus is formed due to electrostatic interactions, i.e., similar to the formation of dusty plasma near other atmosphereless cosmic bodies such as Mercury, the Moon, the satellites of Mars, etc., provided that the distance from the comet to the Sun is at least ~2.5–3.5 AU. On the contrary, if the comet is closer to the Sun, the dynamics of dust particles is determined by the intensity of the gas flow from the comet’s nucleus. The role of plasma–dust processes in the formation of the bow shock wave is considered. It turns out that for a comet with a nucleus of about 1-km radius and a relatively dense dust coma, an important role in the formation of the bow shock wave can be played by anomalous dissipation associated with the process of dust particle charging. Apparently, the nature of such a bow shock wave is similar to the nature of dust ion–acoustic shock waves.