Measurements of chemical erosion in the plasmagenerator PSI-1

The stationary plasma of the PSI-1 facility was used for studying the ion e nergy dependence of chemical erosion of different CFC materials in deuteriu m plasmas. A weak dependence on the bombarding energy was found having a ma ximum between 150 and 200 eV. Furthermore, long term exposure experiments w ith two different CFC materials were carried out showing that the reduction of chemical erosion can be explained by covering the surface with impuriti es. A study of the contribution of energetic neutrals to erosion revealed e ffects of the order of 50%; their influence, however, depends on the plasma conditions.