\textbf{`Predict-first' transport and stability analyses of KSTAR plasmas supporting disruption event characterization and forecasting}

ORAL

Abstract

KSTAR plasmas have reached high stability parameters with normalized beta $\beta_{\mathrm{N}}$ reaching 4.3 at relatively low plasma internal inductance l$_{\mathrm{i}}$ ($\beta_{\mathrm{N}}$/l$_{\mathrm{i\thinspace }}$\textgreater 6), including operation at high $\beta_{\mathrm{N}}$ \textgreater $\beta_{\mathrm{N}}^{\mathrm{no-wall}}$ [1]. Transport analyses are conducted to best understand a disruption-free path toward the KSTAR design target of $\beta_{\mathrm{N}}=$ 5 while aiming to maximize the non-inductive current fraction f$_{\mathrm{NI}}$. Interpretive TRANSP code analyses indicate that f$_{\mathrm{NI}}$ in existing high-performance KSTAR plasmas have reached up to 75{\%}. The predictive capability of TRANSP is used to investigate the effects of the second NBI system recently installed on KSTAR. Extrapolations based on past KSTAR plasma global energy confinement quality (H98y2) and the Greenwald density fraction reveal possible scenarios of fully non-inductive plasmas (f$_{\mathrm{NI}}$\textasciitilde 100{\%}) in the range $\beta _{\mathrm{N}}=$ 3--5 with varied NBI source usage These `predict-first' analyses are used to design high-$\beta $ scenario development experiments for the 2019 run campaign. Ideal and resistive stability of MHD modes in these plasmas are evaluated using the DCON code including the effect of passive stabilizing structure in the device supporting disruption forecasting [1] Y.S. Park, S.A. Sabbagh, et al., Phys. Plasmas \textbf{24} (2017) 012512.

*Work supported by U.S. DoE grant DE-SC0016614.

Authors

  • J.H. Ahn

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

    • Columbia University
  • Y. S. Park

    • Columbia University
  • Y. Jiang

    • Columbia University
  • M. D. Boyer

    • PPPL
  • Z. R. Wang

    • PPPL
  • J. S. Kang

    • NFRI
  • L. Terzolo

    • NFRI
  • A. H. Glasser

    • Fusion Theory and Computation Inc.