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.

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