Analyses of metallic first mirror samples after long term plasma exposure in Tore Supra
Metallic mirrors are foreseen in ITER diagnostic systems as optical elements directly viewing the plasma radiation. In the frame of an EFDA contract, metallic mirror samples have been exposed for long pulse plasma discharges in Tore Supra (TS) in order to investigate surface modifications caused by erosion and re-deposition processes. Three different materials have been selected: mono-crystalline molybdenum (mc-Mo), polycrystalline stainless steel (SS) and copper (Cu). The mc-Mo samples showed after TS exposure almost no surface roughness modifications and the lowest net-erosion. A slight reflectivity reduction, most pronounced in the near UV, is attributed to light absorption in a thin carbon deposit. Cu mirrors showed by far the highest surface roughness, erosion and diffusive reflectivity. Comparative laboratory glow discharge experiments with virgin reference samples and numerical simulations of erosion/deposition confirm the dominant contribution of conditioning procedures to erosion of mirrors exposed (without shutter protection) in Tore Supra.
Bibliographic Reference: An article published in: Fusion Engineering and Design (2006), Volume 81, Issues 1-7, Pages 221-225
Availability: This article can be accessed online by subscribers, and can be ordered online by non-subscribers, at: http://www.sciencedirect.com/science/journal/09203796
Record Number: 200719007 / Last updated on: 2007-04-02
Original language: en
Available languages: en