Carbon Erosion under Heavy Atomic Hydrogen Irradiation

Experiments on erosion and dust formation on graphite materials have been performed using high power induction plasmas of low plasma temperature (∼1 eV) and high atomic hydrogen flux (∼1024 m−2s−1). Chemical sputtering by atomic hydrogen irradiation with incident energy below 1 eV erodes the graphite targets significantly, and generates hydrocarbon particles CxHy. The chemical sputtering yield was roughly estimated to be 0.002-0.005, which is as high as that obtained by ion beam and fusion plasma experiments. Chemical sputtering by hydrogen atoms are generated by recombination in the detached divertor plasmas will have a significant effect on the graphite tile erosion.