Hybrid simulation between molecular dynamics and binary collision approximation codes for hydrogen injection into carbon materials

Molecular dynamics (MD) simulation with modified Brenner's reactive empirical bond order (REBO) potential is a powerful tool to investigate plasma wall interaction on divertor plates in a nuclear fusion device. However, the size of MD simulation box is generally set less than several nm because of the limits of a computer performance. To extend the size of the MD simulation, we develop a hybrid simulation code between MD code using REBO potential and binary collision approximation (BCA) code. Using the BCA code instead of computing all particles with a high kinetic energy for every step in the MD simulation, considerable computation time is saved. By demonstrating a hydrogen atom injection into a graphite by the hybrid simulation code, it is found that the hybrid simulation code works efficiently in a large simulation box.