Three-dimensional distortions of the tokamak plasma boundary: boundary displacements in the presence of resonant magnetic perturbations
Journal article, 2014

The three-dimensional plasma boundary displacements induced by applied non-axisymmetric magnetic perturbations have been measured in ASDEX Upgrade, DIII-D, JET, MAST and NSTX. The displacements arising from applied resonant magnetic perturbations (RMPs) are measured up to +/- 5% of the minor radius in present-day machines. Good agreement can be found between different experimental measurements and a range of models-be it vacuum field line tracing, ideal three-dimensional MHD equilibrium modelling, or nonlinear plasma amplification. The agreement of the various experimental measurements with the different predictions from these models is presented, and the regions of applicability of each discussed. The measured displacement of the outboard boundary from various machines is found to correlate approximately linearly with the applied resonant field predicted by vacuum modelling (though it should be emphasized that one should not infer that vacuum modelling accurately predicts the displacement inside the plasma). The RMP-induced displacements foreseen in ITER are expected to lie within the range of those predicted by the different models, meaning less than +/- 1.75% (+/- 3.5 cm) of the minor radius in the H-mode baseline and less than +/- 2.5% (+/- 5 cm) in a 9MA plasma. Whilst a displacement of 7 cm peak-to-peak in the baseline scenario is marginally acceptable from both a plasma control and heat loading perspective, it is important that ITER adopts a plasma control system which can account for a three-dimensional boundary corrugation to avoid an n = 0 correction which would otherwise locally exacerbate the displacement caused by the applied fields.

physics

stability

edge-localized modes

ITER

pedestal

Author

I. T. Chapman

Culham Science Centre

M. Becoulet

The French Alternative Energies and Atomic Energy Commission (CEA)

T. Bird

Max Planck Society

J. Canik

Oak Ridge National Laboratory

M. Cianciosa

Auburn University

W. A. Cooper

Swiss Federal Institute of Technology in Lausanne (EPFL)

T. Evans

General Atomics

N. Ferraro

General Atomics

C. Fuchs

Max Planck Society

M. Gryaznevich

Culham Science Centre

Y. Gribov

ITER Organization

C. Ham

Culham Science Centre

J. Hanson

Auburn University

G. T. A. Huijsmans

ITER Organization

A. Kirk

Culham Science Centre

S. Lazerson

Princeton University

Y. Liang

Forschungszentrum Jülich

I. Lupelli

Culham Science Centre

R. A. Moyer

University of California

C. Nuehrenberg

Max Planck Society

F. Orain

The French Alternative Energies and Atomic Energy Commission (CEA)

D. Orlov

University of California

W. Suttrop

Max Planck Society

Dimitriy Yadykin

Chalmers, Earth and Space Sciences, Plasma Physics and Fusion Energy

Nuclear Fusion

0029-5515 (ISSN) 1741-4326 (eISSN)

Vol. 54 8 Article no. 083006- 083006

Subject Categories

Fusion, Plasma and Space Physics

DOI

10.1088/0029-5515/54/8/083006

More information

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