Hydrogen chemisorption on the dust grain in divertor plasma

Tokamak divertor plasma is characterized by variety of plasma parameters such as plasma density and temperature, as well as plasma composition and overcoming plasma dynamics processes. A model was surveyed for theoretical study of the interaction of hydrogen with dust surface and the results is applied to the formation of H2 molecule on the dust grain surfaces in the tokamak divertor plasma. In this model, by considering both physisorbed and chemisorbed sites on the grain surface, the adatoms on the surface migrate from one adsorb site to other adsorb site by thermal diffusion and form H2 on the dust grain surfaces. The H2 formation rate on the high temperature dust surfaces in the divertor plasma region has been found for a range of gas temperatures and densities.