To have a better understanding of plasma/wall interactions, a multi–scale procedure was used: molecular dynamics calculations resolved the microscopic length scale and provided quite precise input data for kinetic Monte Carlo calculations (jump frequencies, migration energies, jump step-sizes) used for meso–scale modelling up to the macroscopic system length. In order to cover the entire length-scale involved, from microscopic to macroscopic, several subsequent levels of kinetic Monte Carlo were needed; each providing the necessary input data for the next level. With this procedure, the corresponding time-scales spanning ps atomic interaction times and wall equilibration times of ms were covered. Inclusion of a realistic structure model was also important for porous graphite, where the void structure and orientation of the microcrystallites had to be included. The first results of such a multi–scale calculation were presented.

Multi–Scale Modeling of Hydrogen Isotope Diffusion in Graphite. Warrier, M., Schneider, R., Salonen, E., Nordlund, K.: Contributions to Plasma Physics, 2004, 44[1-3], 307–10