Gas flow and dust acceleration in a cometary Knudsen layer

Details Gas flow and dust acceleration in a cometary Knudsen layer Gas flow and dust acceleration in a cometary Knudsen layer

Aug 1999

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1999p%26ss...47..935s&link_type=abstract

Planetary and Space Science, Volume 47, Issue 8-9, p. 935-949.

Computer Science

16

Scientific paper

An analytical model of the innermost gas-dust coma region is proposed. The kinetic Knudsen layer adjacent to the surface of the cometary nucleus, where the initially non-equilibrium velocity distribution function of gas molecules relaxes to Maxwell equilibrium distribution function and, as a result, the macro-characteristics of gas and dust flows vary several-fold, is considered. The gas phase model is based on the equations for mass, momentum and energy flux conservation, and is a natural development of the [Anisimov, 1968] and [Cercignani, 1981] approaches. The analytical relations between the characteristics of the gas flow on the boundaries of the non-equilibrium layer and the characteristics of the returning gas flow adsorbed by the surface are determined. These values form a consistent basis both for hydrodynamic models of the inner coma and for jet force models. Three particular models are presented: (1) sublimation of a polyatomic one-component gas; (2) sublimation of a two-component polyatomic gas mixture, in both cases from a plane surface; and (3) sublimation of water ice through a porous dust mantle. We conclude that the characteristics of the gas flow emerging from the Knudsen layer over a porous dust mantle is not very sensitive to the structure of the mantle. We also treat the expansion of dust into the coma, concentrating on the interaction between a non-equilibrium gas flow and a test particle. The dynamics of a grain of idealized shape is explored by using several simplifying assumptions for the variation of the drag force. The velocity of a particle at the exterior boundary of the Knudsen layer is thus estimated. Examining various model behaviours of the drag force inside the Knudsen layer, we show that the dust velocity is not sensitive to these variations.

Affiliated with

Also associated with

No associations

Rating

Gas flow and dust acceleration in a cometary Knudsen layer does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Gas flow and dust acceleration in a cometary Knudsen layer, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Gas flow and dust acceleration in a cometary Knudsen layer will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1016410