Recent studies of tungsten-based plasma-facing materials in the linear plasma device STEP

This contribution summarized the recent studies of tungsten-based plasma-facing materials in the linear plasma device like the simulator for tokamak edge plasma (STEP), focusing on the examination of newly developed tungsten (W)-based materials and plasma-induced defects in pure W. Pure W, W-V, W-Y₂O₃ and W-ZrC samples were exposed to a high-flux plasma of ~ 10²¹–10²² m⁻² s⁻¹ with a fluence up to 10²⁶ m⁻² at a surface temperature below 500 K. The investigation of fundamental evolution of plasma-induced defects in pure W indicated a critical role of hydrogen-dislocation interactions. Suppressed surface blistering was observed in all W-based materials, but deuterium desorption behavior and retention were distinct with respect to different materials. The studies showed that the linear plasma device like the STEP was indispensable in the understanding of plasma-material interactions and the qualification of new materials for future fusion reactors.