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.
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Publication: plan to publish results as POP
Presenters
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Matthias Knolker
General Atomics
Authors
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Matthias Knolker
General Atomics
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Theresa M Wilks
MIT-PSFC, MIT
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Tom H Osborne
General Atomics, General Atomics - San Diego
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Philip B Snyder
Oak Ridge National Lab, Oak Ridge National Laboratory
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Huiqian Wang
General Atomics, General Atomics - San Diego
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Carlos A Paz-Soldan
Columbia University
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Oak A Nelson
Columbia University, New York, NY
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Qiming Hu
Princeton Plasma Physics Laboratory
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Joseph T McClenaghan
General Atomics - San Diego, General Atomics
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Morgan W Shafer
Oak Ridge National Laboratory
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Robert S Wilcox
Oak Ridge National Laboratory, Oak Ridge National Lab