The behavior of neutron emissions during ICRF minority heating of plasma at EAST

Zhong, Guoqiang; Cao, Hongchao; Hu, Liqun; Zhou, Ruijie; Xiao, Min; Li, Kai; Pu, Neng; Huang, J.; Liu, Guangzhu; Lin, Shiyao; Lyu, Bo; Liu, Haiqing; Zhang, Xinjun; Team, East

doi:10.1088/0741-3335/58/7/075013

Cited by 13 publications

(5 citation statements)

References 19 publications

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“…This article examines the time resolution of Y n s obtained by the NFM system with ICRH and NBI heating in a deuterium plasma experiment. These two auxiliary heating methods are effective in enhancing the plasma temperature [17]. The high-sensitivity 3 He detector obtains an increase in Y n from 2.7 × 10 10 n/s to 9.5 × 10 10 n/s, an increase that agrees with that of the standard 235 U fusion chamber measurement result.…”

Section: Resultssupporting

confidence: 74%

Development of a wide-range neutron flux monitoring system in EAST

Zhong

et al. 2020

J. Inst.

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A: A wide measurement range for a neutron flux monitoring (NFM) system is developed in the Experimental Advanced Superconducting Tokamak (EAST) for fusion neutron yield measurement, comprising an 3 He proportional counter, a 235 U fission chamber (FC), and a wide dynamic range signal-processing circuit. Two high-sensitivity 3 He detectors operate in counting mode, which is suitable for low neutron yield (Y n ) conditions with ohmic and radio-frequency heating of plasma. Two other FCs are adapted with newly developed digitizers, operating in counting and campbelling modes to satisfy the conditions of wide dynamic range measurement required by neutral beam injection (NBI) experiment. The anti-magnetic-field interference of the FC is examined using two permanent magnets, whose efficiency are calibrated with 2.46 MeV neutrons produced by a Van de Graaff accelerator. Furthermore, the NFM system is implemented in-situ calibration with a 252 Cf neutron source and a remote handling. As a routine diagnostic, the NFM system is successful obtaining the fusion neutron yield for ion cyclotron resonance heating (ICRH) and NBI heating performance evaluation in EAST plasma experiment. K: Nuclear instruments and methods for hot plasma diagnostics; Neutron detectors (cold, thermal, fast neutrons); Detector alignment and calibration methods (lasers, sources, particlebeams); Digital electronic circuits 1Corresponding author.

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Section: Resultssupporting

confidence: 74%

Development of a wide-range neutron flux monitoring system in EAST

Zhong

et al. 2020

J. Inst.

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“…The ion temperature T i measured from charge exchange recombination spectroscopy (CXRS) is also used for pressure calculation [53]. The neutral flux and neutral yields are monitored by a uranium-235 fission chamber [54], and the high-Z impurities are measured by an extreme ultraviolet spectrometer (EUV) [55].…”

Section: Experimental Setup and Diagnosticsmentioning

confidence: 99%

Investigation of Alfvén eigenmodes and Energetic Particle Modes in EAST with neutral beam injection

Xu¹,

Shen²,

Ren³

et al. 2021

Nucl. Fusion

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Alfvén eigenmodes (AEs) and energetic particle modes (EPMs) have been observed in EAST neutral beam injection plasma with the presence of heavy tungsten impurity in the core region. The AEs are identified as toroidal Alfvén eigenmodes (TAEs) with roughly constant frequency f TAE ∼ 100 kHz and a special set of AEs with frequency chirping up from frequency f AE ∼ 70 kHz to f AE ∼ 100 kHz. The frequency of EPMs is around f EPM ∼ 60 kHz, exhibiting with frequency chirping down feature. A transition from EPMs to AEs is found, and the location and mode numbers are measured by experimental diagnostics. Hybrid simulations with the global kinetic-magnetohydrodynamic code M3D-K have been carried out to investigate the observed AEs and EPMs, and linear simulations find the EPM with toroidal mode number n = 2 and poloidal mode number m = 3. Nonlinear simulations show that the EPM frequency chirps down nonlinearly, and then two modes emerge with frequencies around 72.7 kHz and 88.0 kHz: the mode with higher frequency is a TAE, and the other mode is an EPM. Afterward, the TAE disappears quickly with the frequency almost unchanged, and the EPM with lower frequency chirps down continuously. The mode frequencies and locations of the simulated EPM and TAE, as well as the chirping down feature of the EPM frequency, are consistent with the experimental measurements. The transition from EPM to TAE is found to be a self-consistent dynamic of nonlinear evolution with the expel of energetic ions due to EPM.

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“…应等离子体锯齿振荡行为 [15] . 此外, 实验中的安全因子q分布由偏振干涉仪诊断测量数据结合平衡反演程序得到 [16,17] , 利用 235 U裂变电离室中子诊断系统研究和评估等离子体中的快离子行为 [18] , 利用弯晶谱仪诊断系统可以得到等离子体的芯部旋转速度 [19] . 3 实验现象及结果分析 (Sn)可以研究和评估等离子体中的快离子行为 [20] .…”

Section: 实验相关系统unclassified

Influence of resonant magnetic perturbation on sawtooth behavior in experimental advanced superconducting Tokamak

Pan¹,

Duan²,

Xu³

et al. 2023

Acta Phys. Sin.

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Sawtooth oscillations are one of the most important magneto-hydrodynamic (MHD) instabilities in tokamak plasma, which can result in the periodic relaxation of the temperature and density of the core plasma when the safety factor on the magnetic axis (q0) is lower than unity. Due to the periodic relaxation of the plasma core parameters, sawtooth oscillations are beneficial to avoid impurity accumulation in plasma core. However, the large sawtooth crash may trigger other MHD instabilities, like tearing modes (TMs) or neoclassical tearing modes (NTMs), which is a matter of concern for the plasma stability. Therefore, it is essential to control sawtooth for ensuring safe operation in the future tokamaks such as ITER. The resonant magnetic perturbation (RMP) is widely used to control edge-localized modes (ELMs) and divertor heat flux in tokamak. The application of RMP has also been found to affect the sawtooth behaviors. This paper studies the influence of n = 2 RMP coils on sawtooth in experimental advanced superconducting tokamak (EAST), where n is the toroidal mode number of the applied RMP. It is found that the phase difference between upper and lower of RMP coils (△φUL(°)=φU(°)-φL(°) is a notable parameter for affecting sawtooth behavior. The experiments for scanning the phase difference △φUL are carried out. When the phase difference △φUL of n = 2 RMP has been changed, the sawtooth period and amplitude become subsequently different. The minimum sawtooth period and amplitude appear at △φUL=270°. At the same time, neutron yields measured by neutron diagnostic system have the same trend with sawtooth behavior during RMP phase difference scanning. The plasma response to n = 2 RMP is analyzed by using the MARS-F code. The results show that the plasma responses much strongly at the △φUL=270°. The loss of fast ion caused by RMP coils is possibly stronger at the △φUL=270° than that at other phase difference △φUL. The loss of fast ion can decrease its stabilization effect on sawtooth behavior, which results in the reduction of the sawtooth period and amplitude. Further research is needed to optimize the sawtooth control method with RMP to make it compatible with plasma performance.

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The behavior of neutron emissions during ICRF minority heating of plasma at EAST

Cited by 13 publications

References 19 publications

Development of a wide-range neutron flux monitoring system in EAST

Development of a wide-range neutron flux monitoring system in EAST

Investigation of Alfvén eigenmodes and Energetic Particle Modes in EAST with neutral beam injection

Influence of resonant magnetic perturbation on sawtooth behavior in experimental advanced superconducting Tokamak

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