Impurity (helium) ion transport kinetics in a tokamak divertor along magnetic field lines is considered, both analytically and numerically, for the case when the ratio of collisional mean-free-path to the characteristic length of plasma parameter variation is not too small. To obtain the numerical solution of the kinetics equation, the stochastic modeling method is used. For International Thermonuclear Experimental Reactor (ITER) divertor plasma conditions, the influence of thermal force on helium ions is expected to be decreased considerably. As a result, the helium ion flux toward the divertor plates may be significantly enhanced compared to that predicted by the hydrodynamics approach.