EX / P 8-20 1 Potential Safe Plasma Termination Using Laser Ablation of High-Z Impurity in Tokamak

Major plasma disruptions are considered to be a serious problem for development of tokamak fusion reactors. The preliminary experiment results in HL-1M and HL-2A presented here describe the methods of amelioration of plasma current quench in major disruptions using laser ablation of high-Z impurities, which support the design of next generation large tokomaks like ITER. Using injection of impurity with higher electric charge allows us to increase the radiation cooling. Resistive, highly radiating plasma formed prior to the thermal quench, can dissipate both the thermal and magnetic energy. It can be possibly a simple and potential approach to decrease significantly the plasma thermal energy and magnetic energy before a disruption thereby a safe plasma termination is obtained.