Experiments with liquid metal limiters on FTU

The problem of power exhaust is one of the major issues to solve for a future reactor. In the last decade liquid metals as plasma facing components (PFC) have been proposed as possible alternatives to solid materials. The use of liquid metals can improve the lifetime and reliability of PFCs because they are not subjected to erosion with dust formation and to a deterioration of their thermo mechanical properties due to intense hydrogen and helium influx and neutron irradiation as for solid materials. Since 2006 on FTU liquid metal limiters were exposed to plasma discharges. A capillary porous system was adopted to confine the liquid metal to avoid droplet formation. At the beginning we have used Li as liquid metal but in the last year experiments with tin were performed, too. The main goals of the experimental campaigns were to determine the operational window for both materials and the compatibility with plasma performance especially for tin (Z=50).