Erosion and deposition in the ASDEX Upgrade tungsten divertor experiment

Tungsten coated graphite tiles were mounted in the divertor of the ASDEX Up grade tokamak and exposed to approximately 800 plasma discharges. After the experimental campaign, a poloidally complete set of samples was removed. T he poloidal tungsten distribution pattern is presented and compared to thos e of other metallic impurities. The amount of tungsten detected on main cha mber plasma facing components is found to be nearly unaffected by the opera tion of a fully tungsten covered divertor. Modifications of the tungsten su rfaces are analyzed. Deposition is observed to dominate in the inner divert or while erosion prevails in the outer divertor. The influence of this resu lt on the target plate deuterium inventories is demonstrated. Finally, a mo del description for the deuterium inventories observed in the main chamber is presented. (C) 1999 Elsevier Science B.V. All rights reserved.