Erosion of tungsten and carbon markers in the outer divertor of ASDEX-Upgrade

The erosion of tungsten and carbon marker layers was studied in the outer divertor of ASDEX Upgrade. The outer strike point area and a large fraction of the outer baffle are net erosion areas for both materials. The net erosion rate of carbon is about 10–20 times larger than the net erosion rate of tungsten. The erosion is strongly inhomogeneous due to surface roughness, with a large erosion on plasma exposed areas of the rough surfaces, and deposition in recessions and pores.