DiMES contributions to PMI understanding

The Divertor Materials Evaluation System (DiMES) program at General Atomics has been using a sample changer mechanism to expose different plasma-facing materials to the lower divertor of DIII-D to study integrated plasma materials interaction effects in a tokamak and to benchmark modeling codes. We found that for carbon divertor plates, a detached plasma eliminates net erosion in DIII-D. A spectroscopic study of chemical sputtering Indicated the potential improvement of erosion arising from the aging of the first wall material. We also found the importance of the carbon source from the first wall of DIII-D. When lithium was exposed at the divertor we found significant and complicated MHD interactions between the scrape-off layer current in a tokamak and the conducting liquid. This paper is a report on what we have learned and what we plan to do in response to the needs for the plasma facing components (PFC) design for advanced tokamak machines like ITER. Our plan for the study of liquid surface interaction with the plasma will also be presented.