Dust: A new challenge in nuclear fusion research?

Abstract

Small particles (dust) exist in magnetic confinement fusion devices. Their origin is due to plasma–surface interactions. Dust particles may contain significant amounts of hydrogen isotopes, 50% of which will be tritium in future devices. It is important to assess and understand the processes by which dust is formed and by which it interacts with the fusion device and its plasma. Dust may be a safety hazard due to its high chemical reactivity and due to the mobile tritium inventory. Dust may influence the plasma performance and the operation of fusion devices. The radioactive decay of tritium incorporated into carbonaceous dust may lead to its charging and to the formation of a nuclear induced plasma associated with levitation and transport of dust inside the vacuum vessel. Some important aspects of dust in fusion devices will be discussed, making use of information from the area of plasma–surface interactions in fusion devices and from the field of dusty plasma research.