https://doi.org/10.1140/epjs/s11734-024-01461-3
Regular Article
Experimental evidence of aligning the m/n = 2/1 locked mode by RMP for improvement of mode suppression efficiency with electron cyclotron wave on J-TEXT
1
State Key Laboratory of Advanced Electromagnetic Technology, International Joint Research Laboratory of Magnetic Confinement Fusion and Plasma Physics, School of Electrical and Electronic Engineering, Huazhong University of Science and Technology, 430074, Wuhan, People’s Republic of China
a
zychen@hust.edu.cn
b
yanwei1090@hust.edu.cn
Received:
26
September
2024
Accepted:
19
December
2024
Published online:
21
January
2025
Stabilization of tearing modes, neoclassical tearing modes, and the locked modes (LMs) are of great importance for the tokamak plasma operation. The LMs will lead to the degradation of plasma confinement, which may cause major disruptions. The m/n = 2/1 LM islands have been completely suppressed by combination of electron cyclotron wave (ECW) and the externally applied resonant magnetic perturbation (RMP) on J-TEXT. The RMP is employed to control the phase of the 2/1 LMs and align the island’s O-point with the ECW deposition region. The J-TEXT experiment indicates that the 2/1 LM island suppression strategy can reduce the ECW power required for the mode suppression compared the suppression strategy when the island is rotating. Local heating within the magnetic island plays dominant roles on the mode suppression. The electron temperature information inside the magnetic island is provided by the electron cyclotron emission imaging diagnostic when the island is locked by RMP. The experimental results show that the temperature perturbation at the island’s O-point is larger when the island’s O-point is locked at the ECW deposition position than that when the mode is rotating. The effect of the RMP phase on the 2/1 LM suppression by ECW have been investigated. The LM suppression is most effective when the ECW power is properly aligned with the island’s O-point. Disruption avoidance by the suppression of the 2/1 LMs using ECW has been achieved on J-TEXT.
The J-TEXT Team authors listed in “Y.H. Ding et al. 2024 Nucl. Fusion 64 112005”.
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© The Author(s), under exclusive licence to EDP Sciences, Springer-Verlag GmbH Germany, part of Springer Nature 2025
Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.