KINETIC-MODELS FOR DIFFUSION GENERATED BY AN EXTERNAL FORCE

Two kinetic models are used to study the homogeneous color diffusion p roblem in a dilute binary mixture. Both kinetic models incorporate a t emperature dependence in the collision frequencies, which allows for t he consideration of a general repulsive molecular interaction. The mai n transport properties as well as the velocity distribution functions are explicitly obtained in terms of the field strength and the paramet ers characterizing the mixture. The results are illustrated for the tw o extreme cases of Maxwell molecules and hard spheres. A comparison be tween both models and with previous results derived from the Boltzmann equation for Maxwell molecules is carried out.