First wall system in the IGNITEX experiment

Computer simulations to determine wall loading and surface response (e.g. recycling, sputtering and sublimitation) for the proposed ignition experiment, IGNITEX, are presented. The IGNITEX tokamak will ohmically heat a deuterium-tritium plasma to thermonu-clear, fusion ignition conditions. A single-turn coil will be used to produce a 20 Tesla toroidal field for plasma confinement. The first wall will be flat and limiterless with breaks for diagnostic and vacuum ports. The wall will consist of an amorphous carbon film applied to a thick beryllium coating which is plasma jet sprayed onto the vacuum vessel. The carbon film is applied between discharges (by the technique of carbonization) in order to: redeposit carbon eroded during the previous discharge, cover helium ash and other deposited impurities, and regulate the isotope ratio of desorbed, recycled hydrogen. Remote maintenance of areas strongly eroded by major disruptions will be carried out by beryllium plasma jet spraying with a robotic arm. During an ignited plasma discharge, the wall will be exposed to fluxes of neutrons, alpha particles, charge-exchange neutral atoms, photons, and plasma ions and electrons. The response of the wall surface to these fluxes will affect the operation of the machine. Two different time scales are considered in the analysis