Tungsten impurity reduction by ICRH in a high power injection and high performance H-mode discharge on EAST

Tungsten impurity reduction by ICRH in a high power injection and high performance H-mode discharge on EAST

The decrease in tungsten (W) content with the higher ion cyclotron resonance heating (ICRH) power is observed and explained for the first time in a high power injection ( P _inj > 10 MW), high performance ( β _N ∼ 2, β _P ∼ 2.8, n _e / n _GW ∼ 80%, f _BS ∼ 60%) H-mode discharge on experimental ad...

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Main Authors: Zhen Zhou, Shengyu Shi, Ling Zhang, Tao Zhang, Xiaohe Wu, Yunxin Cheng, Wenmin Zhang, Chaowei Mai, Shengyu Fu, Yifei Jin, Xiang Jian, Kaixuan Ye, Lin Yu, Ziqiang Zhou, Jiuyang Ma, Shuqi Yang, Kangning Geng, Gongshun Li, Jia Huang, Fei Wen, Yunfeng Liang, Xiang Gao
Format: Article
Language:English
Published: IOP Publishing 2025-01-01
Series:Nuclear Fusion
Subjects:
ICRH
W reduction
EAST
W neoclassical transport
H minority
isotropic and anisotropic effects
Online Access:https://doi.org/10.1088/1741-4326/adafc4
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Summary:The decrease in tungsten (W) content with the higher ion cyclotron resonance heating (ICRH) power is observed and explained for the first time in a high power injection ( P _inj > 10 MW), high performance ( β _N ∼ 2, β _P ∼ 2.8, n _e / n _GW ∼ 80%, f _BS ∼ 60%) H-mode discharge on experimental advanced superconducting tokamak. Unlike the previous phenomenon of electron cyclotron resonance heating core W control (Shi et al 2022 Nucl. Fusion 62 066031), there is a slight change in the background plasma temperature when higher ICRH is applied, but the toroidal rotational velocity decreases by ∼10 km s ^−1 . Under this condition, the intensity of W unresolved transition array spectral structure in the region of 45–70 Ǻ (which is composed of W ^27+ -W ^45+ line emissions) and W ^44+ density through spectroscopy in the Extreme Ultraviolet region decreases markedly. In addition, the poloidal asymmetry of radiation distribution from the tomographic inversions of Soft x-ray emission is reduced obviously. Theoretical modeling results indicate that the reduction in toroidal rotation leads to less W poloidal asymmetry and neoclassical pinch, which is more efficient in alleviating the core W accumulation than the improvement of isotropic hydrogen (H) minority temperature. The effects of isotropic and anisotropic H minority from ICRH on W transport are compared in the simulation lastly.
ISSN:0029-5515

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