Erosion and re-deposition behavior of plasma facing materials due to tokamak plasma disruption

Plasma irradiation experiments of several kinds of carbon materials and molybdenum were performed in the HL-1M tokamak. The samples emerged into plasma by a depth of 1.5 cm with an angle of 45degrees between sample surface and magnetic field. After approximate to300 plasma discharges with ohmic and NBI heating, melting. microstructure of thin flakes, gas holes and bubbles were found on the surface of molybdenum. No obvious damages were found on the surface of carbon materials, only carbon fibers of 3D-C/C composite were preferentially eroded. Weight changes indicated that most of the samples had little weight loss but few of the samples had large weight increments in which some droplet-shape deposits were found on their surface. Most of the erosion and re-depositions occurred at random on the surface of samples implied that the dominant factor influenced the erosion and re-deposition of plasma facing materials was tokamak plasma disruption. (C) 2002 Elsevier Science B.V. All rights reserved.