Materials research under ITER-like divertor conditions at FOM Rijnhuizen

At FOM Rijnhuizen, linear plasma generators are used to investigate plasma-material interactions under high-density (≤1021 m-3), low-temperature (≤5 eV) plasma bombardment. Research into carbon-based materials has been focused on chemical erosion by hydrogen plasmas. Results from plasma exposure to high-flux (>1023 H+/m2 s) and low-temperature hydrogen plasma indicate silicon carbide has a lower relative rate of gross erosion than other carbon-based materials (e.g. graphite, diamond, carbon-fiber composites) by a factor of 7-10. Hydrogenic retention is the focus of research on tungsten and molybdenum. For target temperatures of 700-1600 K, the temperature dependence of hydrogenic retention is the dominant factor. Damage to the surface by heavy ion irradiation has shown to enhance retention by a factor of 2.5-4.1. Thermal stressing of W via. e-beam thermal cycling also enhances hydrogenic retention by a factor of 2.1 ± 0.2, likely due to the introduction of thermal defects, which act as trapping sites for implanted hydrogenic isotopes.