Abstract
The fluxes and energy distributions of the charge exchange (CX) neutrals as measured at specific locations at the tokamak ASDEX Upgrade (AUG) and the stellarator W7-AS at Garching are discussed as a function of the discharge conditions. For the evaluation of the plasma-wall interaction, knowledge of the energetic neutral fluxes and their energy and angular distributions at all poloidal and toroidal locations are required. For AUG these are obtained from B2-EIRENE computer simulations, taking the experimental results into account. The CX fluxes and the shapes of the spectra vary greatly around a poloidal cross-section. This has a strong effect on the wall erosion by sputtering and hydrogen isotope implantation into the vessel walls. The sputtering of the actual carbon wall, and the effect on possible wall materials, such as tungsten, beryllium, TiC and SiC, are discussed. The depth distribution of the CX neutrals implanted into the walls is calculated for two cases using the TRIMSP code. Saturation, release by glow discharges and permanent retention of the implanted hydrogen isotopes are discussed. This is important for the expected tritium content of the vessel walls of a future D-T fusion device.