Monte-Carlo model for dust/gas interaction in rarefied flows

The cometary atmosphere is a unique phenomenon in the solar system. Owing to its negligible gravity, comets produce highly variable extensive dusty atmospheres with a size much larger than the characteristic size of the cometary nucleus. As the comet approaches the sun, the water vapor with some fraction of other gases sublimates, generating a cloud of gas and dust from the surface of cometary nucleus, which consists of the ice and refractory materials (rocky and organic solids and dust). Sublimating gas molecules undergo frequent collisions in the near nucleus region and photochemical processes. On the basis of the DSMC method a numerical model of cometary comae has been developed. The model includes photolytic processes in the gas phase and interaction of the dust phase with the gas environment.