Mass transfer at the near surface cometary layer. Gas kinetic approach

A selfconsistent model of the surface adjacent non-equilibrium layer is considered in frame of the gas kinetic approach. Twodimensional non-stationary numerical simulation of gas sublimation from the porous ice sample, which is heated by IR radiation, is executed by the DSMC method with weights. Mass transport trough a porous non-isothermal media (both icy and scattering mineral cases) is investigated by the test particle method. We estimate the effective value of the sublimation coefficient of the $\mathrm{H_2O}$ ice under low temperatures. The effective gas production as well as the gas production rate under the porous mineral dust mantle is calculated, taking into account rotation of a cometary nucleus, kinetic character of gas flow, and volume sublimation-condensation of the volatile components of nucleus material.