Characterization of carbon and tungsten micro-particles mobilized by laser irradiation in order to develop an ITER dust removal technique

Due to the safety problem of dust generation in fusion facility, the preliminary step of this work is to demonstrate the ability of laser technique to eject carbon and tungsten particles from Tokamak surfaces. The laser-induced ejection mechanisms will be discussed as a function of absorption properties of dust and surface. Dynamics of mobilized particles have been investigated in order to determine an appropriate technique to collect them. For both carbon and tungsten dusts, we achieved measurements of ejection velocity as a function of laser fluence and ambient pressure. The results demonstrate the ability of the laser technique to eject dusts with very high velocities, even under few Pascal of gas pressure. They give us a better knowledge of the laser interaction mechanisms with carbon and tungsten particles and are very promising for the development of a collection technique.