First results of flowing liquid lithium limiter in HT-7

Two different types of flowing liquid lithium limiters were firstly installed and successfully tested in HT-7 tokamaks in 2012 and some encouraging results were obtained. Two limiters of the first type, called FLiLi limiters, used a thin lithium layer flowing under gravity. The other type had lithium-metal infused trenches (LIMIT) for thermoelectric magnetohydrodynamic drive of the liquid metal flow. The surface of one of the FLiLi limiters was coated by evaporated lithium before liquid lithium was injected by Ar pressure into a special distributor of the limiter. Then the liquid lithium could slowly move along the plasma facing guide surface of the limiter due to gravity. For LIMIT, it was found that liquid lithium could flow along the trenches as expected with a velocity of about 3.7 ± 0.5 cm s^-1 driven by the electromagnetic force, which came from the interaction between the thermoelectric current and magnetic field. Use of flowing liquid lithium limiters in HT-7 resulted in reduction of particle recycling, suppression of impurity emission and improvement of the confinement.