Influence of beryllium plasma seeding on the erosion of carbon

Abstract

This paper is concerned with the influence of beryllium (Be) impurities in a deuterium (D) plasma on the erosion of graphite (C). C targets biased at −50V were exposed to a Be seeded D plasma in the temperature range from 500K to 1280K and Be plasma concentrations in the range from 0.01% to 0.3% in the PISCES-B divertor simulator. It was found that even at these low Be concentrations, the C samples are covered with a shielding Be layer which almost eliminates chemical and physical erosion of the C sample in the observed target temperature range. A combinatorial approach was used to model these experimental results by using the well established Monte Carlo code TRIDYN together with an analytical model. The paper gives an overview of the experimental data, how the modelling results compare with the experiments and how these results can be extrapolated to ITER.