Density functional study of chemical erosion mechanisms in carbon and boron-doped carbon as plasma facing material in tokamaks

Quantum calculations (density functional theory) have been developed in order to propose a new insight into the chemical erosion of pure and doped graphite considered as models for the various carbon materials cladding the first wall of magnetically controlled fusion devices. The elementary processes considered are H, C and CHn, adsorption and desorption, and C, C-2, CH, CCHn, extraction from the surface. The quantum results are compared to experiments through tentative new interpretations of the high-resolution electron energy loss spectroscopy vibration spectra, of the thermal desorption spectroscopy experiments and of the analytical models proposed for chemical erosion. (C) 2003 Elsevier B.V. All rights reserved.