Effects of condensible impurities on the erosion behavior of the plasma-facing materials

Effects of condensible plasma impurities on the material erosion behaviors have been investigated by improving the previous zero-dimensional model. Th e new model can describe more precisely the transition from the enhanced er osion due to impurities to reduced erosion with the formation of the impuri ty film. Model predictions have been proven by the experimental observation s in NAGDIS-I. A water-cooled molybdenum target plate was bombarded with ar gon plasmas into which methane was introduced as carbon impurity. As the fl ow rate of the methane gas was increased, MoI emission line intensity, corr esponding to sputtered particle flux, has been observed to decrease to a gr eat deal. (C) 2001 Published by Elsevier Science B.V.