High flux ion beam acceleration at the 100-eV level for fusion plasma facing material studies

For the investigation of interactions between the low energy ions in fusion edge plasmas and plasma facing materials, new electrodes for beam extraction have been developed to achieve a 100-eV level, high-flux and steady state operation with large irradiation area in the super low energy ion source (SLEIS) facility. The structure of these electrodes has a multi-aperture triode electrodes, whose size is smaller than conventional ones. Namely, these electrodes with the thickness of 0.5 mm have a multi-aperture of 0.9 mm in diameter. The gap distance between electrodes is 0.5 mm. Ion fluxes have been achieved from 1.7 × 1020 to 5.3 × 1020 H/m2 s with the energy from 32 to 102 eV/H. This paper also presents a study about the temperature dependence of blister formation of tungsten by using this new hydrogen ion beam.