Principal processes occurring at simultaneous bombardment of tungsten by carbon and deuterium ions

Simultaneous bombardment of tungsten with deuterium and carbon leads to both tungsten erosion and implantation of carbon and deuterium in the W surface. These processes have been studied experimentally by simultaneous bombardment of magnetron deposited W layers with D and C ions at energies in the keV range. The experimental results were compared to numerical simulations using the TRIDYN code. The key parameter separating steady-state W erosion from continuous growth of a C layer on the surface is the C fraction in the incident flux. The dynamical change of the surface composition with increasing fluence was monitored in situ by ion beam analysis. The experimental results are well reproduced by the TRIDYN simulations, which are based on a kinematic model of ion scattering in the target. Significant contributions by chemical effects outside the scope of the TRIDYN model can therefore be excluded. A negligible contribution of chemical effects is also supported by the measured concentrations of retained D, w...