Evolving collaboration for control & integrated disruption solutions on KSTAR

N.W. Eidietis, J.L. Barr, S.H. Hahn, D.A. Humphreys, E. Schuster, M.L. Walker,

KSTAR Conference

Seoul, South Korea, February 20-22, 2019

Since first plasma, ongoing international plasma control collaborations have provided a mutually beneficial channel to expand KSTAR programmatic capability while providing an international testbed for understanding and developing controls for a long-pulse superconducting device. These collaborations have provided KSTAR with its boundary control system, vertical control system, access to the ITER baseline shape, and an off-normal fault response system. New collaboration activities are being proposed to enable robust operation at high currents (<= 1.4 MA), when the control coils and power systems will near their operational limits. The limits of the vertical stabilization system must be re-assessed at these currents. The ITER baseline scenario need be exported to these higher currents, taking into account the many coils limits it will push against. In this higher current state, with its increased magnetic and thermal energy to dissipate, transient prevention will be important for the KSTAR program as the consequences of disruption will multiply. Continuous monitoring of plasma proximity to stability boundaries and guiding the plasma away from those stability boundaries using profile control methods can maintain the plasma in a stable state without the need for off-normal responses. A new area of collaboration in disruption mitigation is poised to begin with the anticipated installation of dual shattered pellet injectors (SPI) on KSTAR. Collaborative studies on this system will provide invaluable information to reduce uncertainties in the design and operation of the SPI-based baseline ITER disruption mitigation system.