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Enhanced transport at high plasma pressure and subthreshold kinetic ballooning modes in Wendelstein 7-X

Author
Abstract

High-performance fusion plasmas, requiring high pressure B, are not well-understood in stellarator-type experiments. Here, the effect of B on ion-temperature-gradient-driven (ITG) turbulence is studied in Wendelstein 7-X (W7-X), showing that subdominant kinetic ballooning modes (KBMs) are unstable well below the ideal MHD threshold and get strongly excited in the turbulence. By zonal-flow erosion, these sub-threshold KBMs (stKBMs) affect ITG saturation and enable higher heat fluxes. Controlling stKBMs will be essential to allow W7-X and future stellarators to achieve maximum performance.

Year of Publication
2023
Journal
Physical Review Letters
Volume
131
Issue
18
Number of Pages
185101
Date Published
11/2023
Publisher
American Physical Society
URL
https://arxiv.org/abs/2306.03694
DOI
10.1103/PhysRevLett.131.185101
PId
db519aa5e41c2820d32e3f7e7ef21a31
Alternate Journal
Phys. Rev. Lett.
Label
OA
Journal Article
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