On the role of dust in fusion devices

The problem of dust in the vicinity of the walls of Controlled Thermonuclear Devices (CTD) is discussed. It is pointed out that the conditions in the scrape-off layer and divertor are similar to those in low-temperature plasma processing devices where dust is a common occurrence. In the absence of in situ dust diagnostic techniques for present day CTD plasmas, indirect indications of the possible role of dust are analyzed. The most recent data on after-discharge dust suggest that during a discharge dust is confined for a long time inside the edge plasma. It is emphasized that the CTD dust problem assumes more significance for future larger power loadings and longer operation times expected for new devices such as ITER.