Multiscale turbulence in stellarators

Fuente: arXiv
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Main Authors: Merlo, G., Navarro, A. Bañón, Görler, T., Jenko, F., Wilms, F.
Format: Preprint
Published: 2025
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author Merlo, G.
Navarro, A. Bañón
Görler, T.
Jenko, F.
Wilms, F.
author_facet Merlo, G.
Navarro, A. Bañón
Görler, T.
Jenko, F.
Wilms, F.
contents We present the first gyrokinetic simulations of multiscale turbulence in a stellarator, using the magnetic geometry of Wendelstein 7-X (W7-X) and experimentally relevant parameters. A broad range of scenarios is explored, including regimes where electron-temperature-gradient (ETG) turbulence coexists with varying levels of ion-temperature-gradient (ITG) turbulence, as well as cases involving microtearing modes (MTMs) relevant to high-$β$ and reactor-like conditions. Notably, while ETG turbulence does not form radial streamers as in tokamaks, it can still drive significant transport and interact with ion-scale turbulence. In electrostatic ITG-dominated regimes, electron-scale fluctuations erode zonal flows, enhancing ion-scale transport, while ion-scale turbulence suppresses ETG activity. In contrast, under electromagnetic MTM conditions, the isotropic nature of ETG turbulence limits its suppressive effect, allowing MTMs to persist. These findings underscore the critical role of cross-scale effects for accurate transport predictions in W7-X and future stellarators.
format Preprint
id arxiv_https___arxiv_org_abs_2508_06116
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Multiscale turbulence in stellarators
Merlo, G.
Navarro, A. Bañón
Görler, T.
Jenko, F.
Wilms, F.
Plasma Physics
We present the first gyrokinetic simulations of multiscale turbulence in a stellarator, using the magnetic geometry of Wendelstein 7-X (W7-X) and experimentally relevant parameters. A broad range of scenarios is explored, including regimes where electron-temperature-gradient (ETG) turbulence coexists with varying levels of ion-temperature-gradient (ITG) turbulence, as well as cases involving microtearing modes (MTMs) relevant to high-$β$ and reactor-like conditions. Notably, while ETG turbulence does not form radial streamers as in tokamaks, it can still drive significant transport and interact with ion-scale turbulence. In electrostatic ITG-dominated regimes, electron-scale fluctuations erode zonal flows, enhancing ion-scale transport, while ion-scale turbulence suppresses ETG activity. In contrast, under electromagnetic MTM conditions, the isotropic nature of ETG turbulence limits its suppressive effect, allowing MTMs to persist. These findings underscore the critical role of cross-scale effects for accurate transport predictions in W7-X and future stellarators.
title Multiscale turbulence in stellarators
topic Plasma Physics
url https://arxiv.org/abs/2508.06116