Recent EAST Experimental Results and Systems Upgrade in Support of Long-Pulse Steady-State Plasma Operation

Song, Yuntao; Wan, Baonian; Gong, Xianzu; Li, Jiangang; Xin-chao, WU; Liu, Fei; Chen, Junling; Hu, Jiansheng; Xu, G. S.; Lü, Kun; Liang, Yun-Feng; Xiang, Nong; Sun, Youwen; Wang, Liang; Liu, Haiqing; Zhang, Bin; Xia, Tianyang; Huang, J.; Ding, Rui; Zuo, Guizong; Zeng, Long; Zhang, Xinjun; Zang, Qing; Lyu, Bo; Li, Guoqiang; Wang, Xi; Zhang, Jian; Huang, Liansheng; Yao, Damao; Zheng, Jinxing; Wei, Jing; Hu, Yanlan; Yuan, Q.P.; Qian, J.; Zhou, Zhiwei; Wang, Mao; Xu, Chandong; Xie, Yuanlai; Wang, Zhengchu; Zhu, Hai; Song, Wei; Wu, Hsien-Shun; Liu, Xiaoyan; Guo, Fei; Pan, Shengmin; He, Shiying; Zhang, Xiuqing; Chen, Xiaojiao; Xu, Liuwei; Ding, Fang; Hu, Qiya; Zhong, Guoqiang; Lin, Shiyao; Jie, Yinxian; Chen, Ran; Zhang, Yang; Zhao, Hailin; Wu, Zhenwei; Li, Yadong; Yan, Rong; Fu, Jia; Zhang, Tao; Zhang, Shoubiao; Zhuang, Hui; Chen, Yue; Yu, Yaowei; Xiao, Bingjia; Ji, Zhenshan; Shen, Biao; Shi, Li; Wang, Feng; Yuan, Shuai; Cheng, Yan; Ma, Wendong; Zhao, Liang; Liu, Liang; Ding, Bojiang; Hu, Huaichuan; Xu, Wenhai; Wu, Dajun; Yang, Yong; Wang, Mingfu; Li, Jiaxing; Liu, Xuetian; Zhu, Lili; Huang, Yiyun; Wu, Yu; Gao, Xiang; Wang, Xiaojie; Chen, Xiang-Song; Luo, Guang–Nan; Xie, Yahong; Lei, Yanqiang

doi:10.1109/tps.2022.3210124

Cited by 14 publications

(4 citation statements)

References 11 publications

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“…During the EAST upgrade in 2021 [28], two new fast EUV spectrometers were supplemented the previous set, making up a total of four fast EUV spectrometers, namely EUV_Short, EUV_Long_a, EUV_Long_b, and EUV_Long_c. All the spectrometers are equipped with a laminar-type varied-line-spacing concave holographic grating (1200 and 2400 grooves/mm for long and short, respectively).…”

Section: Methodsmentioning

confidence: 99%

Line identification of extreme ultraviolet spectra from aluminum ions in EAST Tokamak plasmas

Zhang,

Zhang

et al. 2024

Phys. Scr.

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Extreme ultraviolet (EUV) spectra emitted from aluminum in the 5–340 Å wavelength range were observed in Experimental Advanced Superconducting Tokamak (EAST) discharges. Several spectral lines from aluminum ions with different degrees of ionization were successfully observed with sufficient spectral intensities and resolutions using three fast-time-response EUV spectrometers. The line identification uses three independent state-of-art computational codes for the atomic structure calculations, which provide the wavelengths and radiative transition probabilities rate coefficients. These programs are HULLAC (Hebrew University - Lawrence Livermore Atomic Code), AUTOSTRUCTURE, and FAC (Flexible Atomic Code). Using three different codes allows us to resolve some ambiguities in identifying certain spectral lines and assess the validity of the theoretical predictions.

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Section: Methodsmentioning

confidence: 99%

Line identification of extreme ultraviolet spectra from aluminum ions in EAST Tokamak plasmas

Zhang,

Zhang

et al. 2024

Phys. Scr.

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“…With the features of advanced non-circular cross-section, strong magnetic field confinement, and fully superconducting magnets, EAST [32,33] has aimed at demonstrating stable, long-pulse, high-performance H-mode plasmas with ITERlike (ITER, International Thermonuclear Experimental Reactor) configuration and operation schemes. The POINT system [31] can provide important electron density profile and plasma current distribution for physics research through interferometry and polarimetry, respectively.…”

Section: The Point System and Fringe Jumpmentioning

confidence: 99%

Phase jump detection and correction based on the support vector machine

Wang

Hanada²,

Sakurai

et al. 2023

Plasma Phys. Control. Fusion

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In general, interferometers are used to perform electron density measurements in magnetically confined plasma, where the electron density is dependent on the refractive index of the plasma. Measurements can be made through comparisons of the phase shift variation between the probe and reference laser beam. The plasma electron density should vary continuously during discharge; however, the fringe jump is a step-like change of the apparent electron density caused by a sudden jump of the measured phase shift. The appearance of fringe jump will degrade the interferometric measurements accuracy. This study attempted to solve the fringe jump problem on the polarimeter-interferometer system of the Experiment Advanced Superconducting Tokamak by proposing a support vector machine model for electron density fringe jump correction. The established model can efficiently classify the fringe jump data from the raw measurement data in a manner robust to noise and interference, and subsequently correct the jump. This model greatly improves the correction efficiency and precision of electron density data from the polarimeter-interferometer diagnostics system (POINT) in the Experiment Advanced Superconducting Tokamak (EAST), and is expected to be embedded into the plasma control system to perform more accurate real-time electron density feedback control. Moreover, the algorithm is not limited to specific fusion devices or interferometer diagnostics, and is applicable to other interferometric measurement systems.

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“…The experimental results presented in this manuscript focus on the EAST tokamak [32][33][34]. EAST is a fully superconducting non-circular section tokamak device with a major radius and a minor radius , designed to achieve long-pulse steady-state high-performance H-mode plasmas at ITER-like configurations, primarily with radio frequency (RF) wave heating schemes.…”

Section: Introductionmentioning

confidence: 99%

Impact of T _i/T _e ratio on ion transport based on EAST H-mode plasmas

LIU 刘,

ZANG 臧,

LIANG 梁

et al. 2024

Plasma Sci. Technol.

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At the EAST tokamak, the ion temperature (Ti) is observed to be clamped around 1.25 keV in ECR-heated plasmas, even at core electron temperatures up to 10 keV (depending on the electron cyclotron resonance heating (ECRH) power and the plasma density). This clamping results from the lack of direct ion heating and high levels of turbulence driven transport. Turbulent transport analysis shows that trapped electron mode (TEM) and electron temperature gradient (ETG) driven modes are the most unstable modes in the core of ECR-heated H-mode plasmas. Nevertheless, recently it was found that the Ti/Te ratio can increase further with the fraction of the Neutral Beam Injection (NBI) power, which leads to a higher core ion temperature (Ti0). In NBI-heating-dominant H-mode plasmas, the ion temperature gradient (ITG) driven modes become the most unstable modes. Furthermore, a strong and broad internal transport barrier (ITB) can form at the plasma core in high-power NBI heated H-mode plasmas when the Ti/Te ratio approaches ~1, which results in steep core Te and Ti profiles, as well as a peaked ne profile. Power balance analysis shows a weaker Te profile stiffness after the formation of ITBs in the core plasma region, where Ti clamping is broken, and the core Ti can increase further above 2 keV, which is 80% higher than the value of Ti clamping in ECR-heated plasmas. This finding proposes a possible solution to the problem of Ti clamping in EAST and demonstrates an advanced operational regime with formation of a strong and broad ITB for future fusion plasmas dominated by electron heating.

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Recent EAST Experimental Results and Systems Upgrade in Support of Long-Pulse Steady-State Plasma Operation

Cited by 14 publications

References 11 publications

Line identification of extreme ultraviolet spectra from aluminum ions in EAST Tokamak plasmas

Line identification of extreme ultraviolet spectra from aluminum ions in EAST Tokamak plasmas

Phase jump detection and correction based on the support vector machine

Impact of T _i/T _e ratio on ion transport based on EAST H-mode plasmas

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Recent EAST Experimental Results and Systems Upgrade in Support of Long-Pulse Steady-State Plasma Operation

Cited by 14 publications

References 11 publications

Line identification of extreme ultraviolet spectra from aluminum ions in EAST Tokamak plasmas

Line identification of extreme ultraviolet spectra from aluminum ions in EAST Tokamak plasmas

Phase jump detection and correction based on the support vector machine

Impact of T i/T e ratio on ion transport based on EAST H-mode plasmas

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Product

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Impact of T _i/T _e ratio on ion transport based on EAST H-mode plasmas