MHD stability of negative triangularity DIII-D plasmas

Negative triangularity (NT) experiments in DIII-D point to an emergent reactor scenario free of sawteeth, endowed with benign, nondisruptive n = 2 tearing modes, which experience q _min $ \geqslant $ 1 similar to the positive triangularity hybrid scenario. Plasmas exhibiting this behavior attain ${\...

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Bibliographic Details
Published in:Nuclear Fusion
Main Authors: W. Boyes, F. Turco, J. Hanson, A. Marinoni, A. Turnbull, M. Austin, G. Navratil
Format: Article
Language:English
Published: IOP Publishing 2023-01-01
Subjects:
MHD
scenarios
negative triangularity
tearing modes
Online Access:https://doi.org/10.1088/1741-4326/acd564
Description
Summary:Negative triangularity (NT) experiments in DIII-D point to an emergent reactor scenario free of sawteeth, endowed with benign, nondisruptive n = 2 tearing modes, which experience q _min $ \geqslant $ 1 similar to the positive triangularity hybrid scenario. Plasmas exhibiting this behavior attain ${\beta _{\text{N}}} > 3$ , high enough to reconsider long held views of NT stability. Ideal MHD and tearing stability analysis of well-diagnosed equilibrium reconstructions of experimental hybrid-like plasmas predict that among shape parameters, MHD stability limits are only sensitive to average triangularity. Operation is predicted to be possible at ${\beta _{\text{N}}}$ relevant to upcoming tokamaks and commercial NT reactors.
ISSN:0029-5515

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