A BASIC STUDY ON EROSION-REDEPOSITION PROCESSES IN THE BOUNDARY PLASMA REGION

In this work, experimental and modeling studies have been performed to understand impurity atomic excitation-ionization and transport proces ses in relation to the material erosion and redeposition behavior unde r plasma exposure. The experiments were performed with a laboratory pl asma bombarding the target materials: the isotropic graphite and the b oronized layer. Impurities in the plasma were optically identified and the observed density spatial profiles were obtained. A numerical mode l of impurity transport considering momentum conservations was develop ed in order to examine the observed spatial profile of impurity densit ies. The densities of C+ and B+ were dominant in the region adjacent t o the target and those of higher charged particles increased as they w ere transported away from the target. The density of boron species was more concentrated in the target region than carbon species. These phe nomena in experimental results were confirmed numerically.