STUDY OF GROSS AND NET EROSION IN THE ASDEX UPGRADE DIVERTOR

Erosion of carbon and tungsten in the divertor of ASDEX Upgrade was in vestigated by surface analysis of target tile probes. The probes were exposed in the divertor using a manipulator system. Erosion of carbon was measured by graphite probes covered with a 150 nm layer of (13) C isotope to distinguish from the intrinsic carbon content. Tungsten ero sion was measured by similar probes with 1-20 nm tungsten markers evap orated on the surface. From the measured erosion, sputtering yields we re determined using plasma parameters at the target plates obtained fr om flush mounted Langmuir probes.