Disruption process control through multi-scale interaction in KSTAR*

Comprehending the factors that influence disruption dynamics and mastering their control is pivotal for advancing fusion reactor development. In magnetic fusion devices, plasma disruptions often arise from the disturbance of magnetic field structures due to phenomena like the growth of magnetic islands. Interestingly, even seemingly identical magnetic islands can exhibit markedly different disruption characteristics based on the turbulence levels surrounding them. Weak turbulence necessitates stronger magnetic island drivers to precipitate disruption, thereby potentially delaying the onset of disruptions. This study explores the controlled manipulation of macro-scale plasma disruptions by modulating micro-scale turbulence influenced by meso-scale poloidal flows, employing additional n=2 non-axisymmetric magnetic field perturbations in KSTAR discharges. In addition, GENE gyrokinetic simulations have performed replicating the discharges, of which results qualitatively agree with experimental observations. Interestingly, GENE shows reduction of outward heat flux around q=2 where 2/1 magnetic island locate, by the inclusion of 3/2 island at q=3/2. Results of further simulations to study this nonlocal feature of the multi-scale interactions among micro-turbulence, meso-scale flows and macro-scale non-axisymmetric magnetic field perturbations, and the condition for the multi-scale-interaction-based disruption control will be presented.