The purpose of this plan is: to develop a limiter or limiters (subjected to high heat and particle fluxes at plasma edge) for long pulse operation of tokamak fusion devices; to study the particle removal with the limiters; and to study and develop the methods for protections against disruptions and other abnormal operation, such as run-away electrons and arcing. Alcator A has a peak heat of 5 kW/cm/sup 2/ and high particle flux, and as such is an ideal test facility. Access is adequate for small scale tests