A basic study on erosion—redeposition processes in the boundary plasma region

Abstract

In this work, experimental and modeling studies have been performed to understand impurity atomic excitation—ionization and transport processes in relation to the material erosion and redeposition behavior under plasma exposure. The experiments were performed with a laboratory plasma bombarding the target materials: the isotropic graphite and the boronized layer. Impurities in the plasma were optically identified and the observed density spatial profiles were obtained. A numerical model of impurity transport considering momentum conservations was developed in order to examine the observed spatial profile of impurity densities. The densities of C + and B + were dominant in the region adjacent to the target and those of higher charged particles increased as they were transported away from the target. The density of boron species was more concentrated in the target region than carbon species. These phenomena in experimental results were confirmed numerically.