Dynamic interaction between disruptive plasma and wall in the small tokamak HYBTOK-II

Dynamic behaviour of plasma–wall interactions has been investigated by using triple probe and Hα line emission of disruptive plasma in small tokamak HYBTOK-II. As the features of the disruption discharge of HYTOK-II, it was found that the waveform of plasma current quench has two phases of the first slow and the subsequent fast decays. The interaction between plasma and wall was found to be largest during fast decay phase in the course of whole discharge. The increase of plasma–wall interactions is thought to be caused by both of convective pump-out of the plasma particles in the core region and the rapid movement of plasma to the inner wall at the start time of two decay phases.