Surface temperature measurement in the medium and long wavelength infrared range on MAST

19th International Conference on Plasma-Surface Interactions in Controlled Fusion Devices (PSI), Univ Calif, Gen Atom, San Diego, CA, MAY 24-28, 2010; International audience; Experiments and theoretical investigations of surface temperature measurement in the medium and long wavelength infrared range carried out on MAST show that a nonhomogenous surface temperature distribution due to the surface state (micro-metric hot-spots and/or surface roughness) can lead to a significant difference (up to similar to 40%) between both wavelengths. The over-estimation of the bulk temperature decreases with wavelength and the discrepancy observed on MAST can be reproduced using a hot-spot simulation model, by varying the dust size and the dust coverage such that a coverage of 0.2 parts per thousand with 1 mu m dust size which is consistent with the observations. The over-estimation of the bulk temperature is assessed at medium and long wavelength as a function of dust contribution (coverage/size). The effect is also assessed in different conditions (temperature of the bulk as well as the incident power flux). (C) 2010 Elsevier B.V. All rights reserved.