Publications Details
DiMES divertor erosion experiments on DIII-D
Thin metal films (∼ 100 nm thick) of Be, W, V and Mo, were deposited on a Si depth-marked graphite sample and exposed to the steady-state outer strike point on DIII-D in order to measure their respective erosion rates. Gross erosion rates and redeposition lengths are found to decrease with the atomic number of the metallic species, as expected. The maximum net erosion rate for carbon, which occurs near the separatrix, increased from 4 to 16 nm/s when the incident heat flux was increased from 0.7 to 2 MW/m2. Comparisons of the measured carbon erosion with REDEP code calculations show good agreement for both the absolute net erosion rate and its spatial variation. Visible spectroscopic measurements of singly ionized Be (BeII 4674 Å) have determined that the erosion process reaches steady-state during the exposure.