Simulation study of dynamical material mixing on tungsten surfaces at elevated temperatures due to hydrogen and carbon mixed ion beam irradiation

Using the EDDY simulation code for ion–solid interactions, dynamical material mixing on W surfaces due to simultaneous impact of 0.33 keV H+ and 1 keV C+ impurity has been studied in terms of the C impurity concentration and target temperature. Fluence-evolution of erosion/deposition at the surface is dependent on the C impurity concentration and the temperature. For low C impurity concentration such as C:0.11%, the erosion is enhanced with increasing temperature, whereas, for high C impurity concentration such as C:4.50%, the deposition is suppressed. For C:2.90%, the growth rate is changed from erosion to deposition, and then, a reverse change occurs with increasing temperature. These changes are due to synergistic effects of thermal diffusion and reflective scattering collisions. The depth profile of C impurity deposited on the target also depends on the C impurity concentration and the temperature. Significant diffusion causes growth of the W–C mixed layer in the bulk.