MEASUREMENTS OF CARBON AND TUNGSTEN EROSION DEPOSITION IN THE DIII-D DIVERTOR

Net erosion/deposition rates of carbon and tungsten were measured at the outer strike point of the divertor plasma on the floor of the DIII-D tokamak during deuterium H-mode operation at an average power deposition of about 45 W/cm(2). For carbon, net erosion rates of up to 4 nm/s were found. For a tungsten film, no appreciable erosion was detected. However, measurements of deposited tungsten on adjacent carbon surfaces indicated a net W erosion rate of 0.06 nm/s.