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RMP optimization on KSTAR

ORAL

Abstract

A new systematic RMP optimization represents a step toward safe ELM suppression by isolating the edge from core resonant fields. The optimization identifies the edge-optimized RMPs (ERMPs) in principle from the external fields without core-resonant response but keeps its efficiency in ELM suppression with the actual coils for experimental implementation. The ERMP is validated with accurate predictions, where it provides a 100% increase of ELM suppression window compared to the standard RMP in KSTAR. Furthermore, the new scheme allows the optimization across scenarios such that it would suppress ELMs in the H-mode phase but remain stable in the L-mode phase. This integrated optimization enabled the application of 3D fields before the L-H transition and showed the possibility to control the ELMs through the entire periods of discharge, including the first ELM crash which alone could lead to significant damage to the plasma-facing components. It turns out that the ERMP penetrated the edge resonant surface already before L-H transition with the zero perpendicular flow and delayed L-H transition timing with decreased non-linear interaction between zonal flow and turbulence. This result highlights the need to integrate different resonant field physics through the entire discharge.

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Publication: [1] S.M. Yang, J.-K. Park, N.C. Logan et al., NF 60, 096023 (2020)

Presenters

  • SeongMoo Yang

    Princeton Plasma Physics Laboratory, Princeton Plasma Physics Laboratory, Princeton, U.S.A.

Authors

  • SeongMoo Yang

    Princeton Plasma Physics Laboratory, Princeton Plasma Physics Laboratory, Princeton, U.S.A.

  • Jong-Kyu Park

    Princeton Plasma Physics Laboratory

  • Nikolas C Logan

    Lawrence Livermore Natl Lab, Lawrence Livermore National Laboratory, LLNL

  • Y. M. Jeon

    Korea Institute of Fusion Energy, Korea Institute for Fusion Energy

  • Qiming Hu

    Princeton Plasma Physics Laboratory

  • SangKyeun Kim

    Princeton University, Princeton Plasma Physics Laboratory, Princeton University, Princeton, U.S.A.

  • Yongkyoon In

    Ulsan Natl Inst of Sci & Tech, Ulsan National Institute of Science and Technology, Ulsan National Institute of Science and Technology (UNIST)

  • Wonha Ko

    Korea Institute of Fusion Energy, Korea Institute for Fusion Energy, Korea Institute of Fusion Energy (KFE)

  • Gunyoung Park

    Korea Institute for Fusion Energy, Korea Institute of Fusion Energy (KFE)

  • J. H. Lee

    Korea Institute of Fusion Energy, Korea Institute for Fusion Energy, Daejeon, Republic of Korea, Korea Institute of Fusion Energy (KFE)

  • Jaewook Kim

    Korea Institute of Fusion Energy, Korea Institute of Fusion Energy, Daejeon, Korea, Korea institute of Fusion Energy, Korea Institute of Fusion Energy (KFE)

  • Yong-Su Na

    Seoul National University, Seoul National University, Seoul, Korea