Highlights of KSTAR-PPPL Collaborations on 3D Fields, Disruptions, Control, and Impurity Powder Dropper

PPPL has several ongoing collaborations on KSTAR in control of plasma transport and ELMs with 3D fields, disruption forecasting, and use of the Impurity Powder Dropper (IPD) as an actuator for real-time wall conditioning. Applied 3D fields were optimized to successfully suppress ELMs to achieve KSTAR’s record-high β_N = 2.6 and record long ELM suppression of 45 s duration by integrating adaptive ELM control. Validation between TM1 simulations and KSTAR experiments reveal key characteristics of density pump-out by pedestal-foot island formation induced by RMP. Coupling of the nonlinear 3D MHD JOREK code with the PENTRC neoclassical toroidal viscosity code has consistently captured the experimentally observed bifurcation and density pump-out with increasing RMP fields. Implementation of real-time measurements of MHD modes, plasma rotation, and ECE has permitted developing disruption forecasting and feedback algorithms to help avoid disruptions. Dynamic control of the IPD has been implemented for real-time wall conditioning to improve KSTAR’s long pulse capability with its new tungsten divertor with experiments due in late 2023. Future experiments are planned to compare glow discharge boronization and real-time wall conditioning with the IPD considering ITER plans for a full tungsten wall and divertor. The latest results to help KSTAR achieve its long pulse goals and plans for future collaborations will be presented.