Suppression of core turbulence by profile shaping in Wendelstein 7-X

In the Wendelstein 7-X magnetic confinement experiment, a reduction of turbulent density fluctuations as well as anomalous impurity diffusion is associated with a peaking of the plasma density profile. These effects correlate with improved confinement and appear largely due to a reduction of anomalo...

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Published inarXiv.org
Main Authors Stechow, A v, Grulke, O, Wegner, Th, Proll, J H E, Alcusón, J A, Smith, H M, Baldzuhn, J, Beidler, C D, Beurskens, M N A, Bozhenkov, S A, Edlund, E, Geiger, B, Huang, Z, d, O P, Fuchert, G, Langenberg, A, Pablant, N, Pasch, E, Porkolab, M, Rahbarnia, K, Schilling, J, Scott, E R, Thomsen, H, Vanó, L, Weir, G, The W7-X Team
Format Paper
LanguageEnglish
Published Ithaca Cornell University Library, arXiv.org 05.10.2020
Subjects
Confinement
Density gradients
Heat flux
Plasma density
Reduction
Turbulence
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Summary:In the Wendelstein 7-X magnetic confinement experiment, a reduction of turbulent density fluctuations as well as anomalous impurity diffusion is associated with a peaking of the plasma density profile. These effects correlate with improved confinement and appear largely due to a reduction of anomalous transport as the change in neoclassical transport is small. The observed decrease of turbulent heat flux with increased density gradients is in agreement with nonlinear gyrokinetic simulations, and has been attributed to the unique geometry of W7-X that limits the severity of trapped electron modes.
ISSN:2331-8422