Measurements on components subjected to high heat flux and special conditions will be characterized from a structural, chemical and thermal point of view. The PhD student will have to become familiar with the scientific setups for carrying out all these measurements. First, the emissivity of the surfaces will be measured in the IUSTI laboratory thanks to an existing experimental bench that will have to be upgraded, in particular to access the spectral emissivity. Then, structural and spectroscopic surface analyses will be realized in the PIIM laboratory and the electron microscopy platform. For the structural part, AFM, confocal microscopy, SEM and possibly X-ray microtomography will be used for the characterization of the surface state (deposit, crack networks, microcracks…). In the case of the surface composition and the presence of oxide layers, EDX and Raman spectroscopy can be used. All these analyses will have to be performed both on samples prepared in the laboratory, in particular to study the influence of the thickness of an oxide layer, and on components that have undergone transformations in the WEST tokamak. The aim of the thesis will be to link the emissivity evolutions measured in-situ (and also post-mortem) to the plasma scenarios. Comparison with plasma wall interaction modelling (such as SOLEDGE-EIREN + ERO2.0) will help to understand the full map of emissivity (impurity transport in the edge plasma) as well as local distribution patterns (local erosion and redeposition).