Dependence of plasma rotation braking on ion temperature and non-axisymmetric magnetic field spectra in high normalized beta KSTAR plasmas

POSTER

Abstract

H-mode plasma operation of KSTAR has surpassed the ideal MHD $n =$ 1 no-wall limit by achieving high normalized beta up to 2.8 while reducing plasma internal inductance to near 0.7. Non-axisymmetric fields were applied using in-vessel control coils with varied $n$~$=$~2 field spectra, ECH, and supersonic molecular beam injection to alter the plasma toroidal rotation profile in high beta H-mode plasmas and to analyze their distinct effects on the rotation. The rotation profile was significantly altered in a self-similar fashion with rotation level reduced by more than 60{\%} without tearing activity or mode locking using the full range of techniques. Changes in the steady-state rotation profiles are analyzed to determine the physical aspects of NTV. The NTV scaling with $\delta B^{2}$ shows good agreement with the measured profile change. The NTV coefficient scales as $T_{i}^{2.27}$, in general agreement with the low collisionality ``1/$\nu $'' regime scaling of NTV theory. Resistive tearing stability determined by examining the classical tearing stability index is discussed, and the result is compared with two-fluid resistive MHD solutions from the M3D-C$^{1}$ code. The effect of plasma rotation profile on tearing stability is examined using the M3D-C$^{1}$ analyses.

*Supported by U.S. DOE grant DE-FG02-99ER54524.

Authors

  • Y.S. Park

    • Columbia U.
    • Columbia University
  • S.A. Sabbagh

    • Columbia University
    • Columbia Univ
    • Columbia U.
  • J.W. Berkery

    • Columbia U.
    • Columbia University
  • J.M. Bialek

    • Columbia University
  • W.H. Ko

    • National Fusion Research Institute
    • NFRI
    • NFRI, Korea
  • Y.M. Jeon

    • National Fusion Research Institute, Daejeon, Korea
    • NFRI
    • NFRI, Korea
  • J.G. Bak

    • NFRI, Korea
  • S.H. Hahn

    • National Fusion Research Institute
    • NFRI, Korea
  • J. Kim

    • NFRI, Korea
  • S.G. Lee

    • National Fusion Research Institute
    • NFRI, Korea
  • Stephen Jardin

    • Princeton Plasma Physics Laboratory
    • PPPL
    • Princeton Plasma Physics Laboratory, Princeton, NJ, USA
  • M.J. Choi

    • POSTECH, Korea
  • G.S. Yun

    • POSTECH
    • POSTECH, Korea
  • H.K. Park

    • UNIST
    • Unist University
    • UNIST, Korea