Control advances for achieving the ITER baseline scenario on KSTAR

ORAL

Abstract

Control methodologies developed to enable successful production of ITER baseline scenario (IBS) plasmas on the superconducting KSTAR tokamak are presented: decoupled vertical control (DVC), real-time feedforward (rtFF) calculation, and multi-input multi-output (MIMO) X-point control. DVC provides fast vertical control with the in-vessel control coils (IVCC) while sharing slow vertical control with the poloidal field (PF) coils to avoid IVCC saturation. rtFF compensates for inaccuracies in offline PF current feedforward programming, allowing reduction or removal of integral gain (and its detrimental phase lag) from the shape controller. Finally, MIMO X-point control provides accurate positioning of the X-point despite low controllability due to the large distance between coils and plasma. Combined, these techniques enabled achievement of IBS parameters (q$_{\mathrm{95\thinspace }}=$ 3.2, $\beta_{\mathrm{N}}=$ 2) with a scaled ITER shape on KSTAR. n$=$2 RMP response displays a strong dependence upon this shaping..

Authors

  • N.W. Eidietis

    GA, General Atomics

  • Jayson Barr

    Oak Ridge Associated Universities, General Atomics, Oak Ridge Assoc Univ

  • S. H. Hahn

    NFRI, Natl Fusion Res Inst, National Fusion Research Institute

  • D.A. Humphreys

    General Atomics

  • Yongkyoon In

    NFRI, NFRI, Daejeon, Korea, National Fusion Research Institute, Natl Fusion Res Inst

  • Y. M. Jeon

    NFRI, NFRI, Daejeon, Korea, National Fusion Research Institute

  • M.J. Lanctot

    US DOE

  • D. Mueller

    Princeton Plasma Physics Laboratory, PPPL, Princeton Plasma Phsyics Laboratory

  • M.L. Walker

    General Atomics, GA, Gen. Atomics