Non-equilibrium kinetic versus Monte Carlo modelling of hydrogen–surface interactions

The study presents a contribution to the modelling of processes with H2 molecules in both ground and vibrationally excited state and with H atoms. Attention is focused on the surface processes, which besides volume collisions, can influence significantly the vibrational population of hydrogen molecules. It is important to know this population since it opens a variety of low-energy channels at the cold edge of fusion plasmas. We have developed a simple kinetic model to estimate the particle fluxes formed by vibrational excitation and dissociation of hydrogen on metal surfaces, at low pressures and low temperatures. Comparison with the experiment shows that it grasps the main of the underlying physics: further improvements accompanied by more complete vibrational state-selective data are foreseen.