Modelling for near-surface transport dynamics of hydrogen of plasma facing materials by use of cellular automaton

Shimura, Kenichiro*; Yamaguchi, Kenji; Terai, Takayuki*; Yamawaki, Michio*

In this study, the kinetics of desorption of adsorbed hydrogen from an ideal metallic surface is modeled in Cellular Automaton (CA). The modeling is achieved by downgrading the surface to one dimension. The model consists of two parts that are, surface migration and desorption. The former is attained by randomly sorting the particles at each time, the latter is realized by modeling the thermally-activated process. For the verification of this model, thermal desorption is simulated and then the comparison with the chemical kinetics is carried out. Excellent agreement is observed from the result. The overall results show that this model is reasonable to express the recombinative desorption of two chemisorbed adatoms. Although the application of this model is limited to second-order reaction case, it can be believed that the groundwork of modeling the transport dynamics of hydrogen through the surface under complex conditions is established.