Impact of Novel Lithium Coating Apparatus on Plasma Behavior Improvement in Experimental Advanced Superconducting Tokamak

A novel type of deposition tool was developed to improve the uniformity and service lifetime of the Li-coatings, grown on the walls of vacuum chamber dedicated to Experimental Advanced Superconducting Tokamak (EAST) and serving to reduce recyclability and suppress impurity contamination of the plasma.The original work was design of the crucible with three vaporizing holes.The test results show that the new evaporator outperforms the conventional one not only because of better uniformity, stronger interfacial adhesion and longer service lifetime of the Li-coatings, but also because of a considerable reduction of the recyclability, impurity contamination and total radiation power of the plasma; and that the Li-film fully covered the lower graphite divertor's surfaces.Besides, another newly-designed inter-shot evaporator is capable of injecting Li-vapor and growing new Li-layers at the interval of discharges to restore the pre-coated lithium films.