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Progress in extending the DIII-D high-β<sub>P</sub> scenario to long pulse on EAST

POSTER

Abstract

Recent experiments on EAST have made progress in extending performance and duration of the high-βP scenario, with world record duration of 403 s at βP~2.5, βN~1.5. Unlike the high βP scenario on DIII-D with large radius internal transport barriers (ITBs) in all channels, on EAST the ITB is only visible in the electron temperature profile, at small radius. Transport analysis suggests that, at large radius, these plasmas are limited by ITG turbulence, despite low ion temperature gradients. Significant turbulence reduction is predicted with higher qmin and reduced magnetic shear. Experiments using EC waves for early heating, produced higher qmin plasmas with lower internal inductance, but lacked the power to sustain those conditions via sufficient bootstrap current. New experiments have been planned using TRANSP time-dependent modeling to optimize early EC heating timing, power, and deposition profile. It is predicted that strong off-axis EC heating will also cause the LHCD profile to peak off-axis. This could help sustain the high qmin profile, together with additional heating power.

Presenters

  • Andrea M. M Garofalo

    General Atomics, General Atomics - San Diego

Authors

  • Andrea M. M Garofalo

    General Atomics, General Atomics - San Diego

  • Wilkie Choi

    General Atomics, GA

  • Siye Ding

    General Atomics

  • Xianzu Gong

    Institute of Plasma Physics, Chinese Academy of Sciences, ASIPP

  • Juan Huang

    ASIPP

  • Bin Zhang

    ASIPP

  • Paul T Bonoli

    Massachusetts Institute of Technology MI

  • Seung Gyou Baek

    Massachusetts Institute of Technology MI, Massachusetts Institute of Technology, MIT Plasma Science and Fusion Center

  • Gregory M Wallace

    MIT PSFC