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Advances in RMP ELM Suppression through Establishment of Record Pressure and Temperature Pedestals

ORAL · Invited

Abstract

.Recent experiments dedicated to the control of edge localized modes (ELMs) using resonant magnetic perturbations (RMPs) on DIII-D have achieved significant advances towards ITER and future fusion power plants, achieving record pedestal pressures. For the first time, ELMs were suppressed at maximum toroidal field BT=2.17 T and plasma current IP=2.0 MA in the ITER similar shape (ISS). Moreover, the experiment followed a successful Predict First Approach: Pedestal pressure and behavior was predicted using the EPED model, ELM suppression windows in q95 were targeted based on previous GPEC simulations. Discharges started from a peeling-limited Super H-mode high performance phase, and then transitioned into ELM suppression. Typically, RMP experiments start with lower density/performance by early RMP coil activation. Combining high field and current allows exploration of lower collisionality pedestals at high density (here νe,ped~0.2), the expected environment for future fusion reactors. The suppression lasted for multiple energy confinement times. ELM suppression in the ISS plasma was achieved for both q95 = 3.3 and q95 = 3.6, the former achieving record stationary pedestal pressures of pped=14 kPa (pe,ped=6.5 kPa, pav=52 kPa), exceeding previous RMP suppression records by 30 %. These experimental results and the EPED codes are used to extrapolate to ITER, resulting in a pedestal height of 60 kPa with RMPs and show a peeling limited pedestal. Using TGLF and TGYRO to predict the core plasma, this results in 300 MW of fusion power, and Q=6 for ITER’s active phase. These results are based on a viable core-edge-solution and more realistic than the 500 MW/Q=10, since those assumes fully stationary type I ELM pedestals. Our work raises confidence in combining high pedestals and ELM control for developing the updated ITER research plan.

Publication: plan to publish results as POP

Presenters

  • Matthias Knolker

    General Atomics

Authors

  • Matthias Knolker

    General Atomics

  • Theresa M Wilks

    MIT-PSFC, MIT

  • Tom H Osborne

    General Atomics, General Atomics - San Diego

  • Philip B Snyder

    Oak Ridge National Lab, Oak Ridge National Laboratory

  • Huiqian Wang

    General Atomics, General Atomics - San Diego

  • Carlos A Paz-Soldan

    Columbia University

  • Oak A Nelson

    Columbia University, New York, NY

  • Qiming Hu

    Princeton Plasma Physics Laboratory

  • Joseph T McClenaghan

    General Atomics - San Diego, General Atomics

  • Morgan W Shafer

    Oak Ridge National Laboratory

  • Robert S Wilcox

    Oak Ridge National Laboratory, Oak Ridge National Lab