Liquid metals as alternative solution for the power exhaust of future fusion devices: status and perspective

Applying liquid metals as plasma facing components for fusion power-exhaust can potentially ameliorate lifetime issues as well as limitations to the maximum allowed surface heat loads by allowing for a more direct contact with the coolant. The material choice has so far been focused on lithium (Li), as it showed beneficial impact on plasma operation. Here materials such as tin (Sn), gallium (Ga) and aluminum (Al) are discussed as alternatives potentially allowing higher operating temperatures without strong evaporation. Power loads of up to 25 MW m(-2) for a Sn/W component can be envisioned based on calculations and modeling. Reaching a higher operating temperature due to material re-deposition will be discussed. Liquids typically face stability issues due to j x B forces, potential pressure and magnetohydrodynamic driven instabilities. The capillary porous system is used for stabilization by a mesh (W and Mo) substrate and replenishment by means of capillary action.