Observations of compound sawteeth in ion cyclotron resonant heating plasma using ECE imaging on experimental advanced superconducting tokamak

Hussain, Azam; Zhao, Zhenling; Xie, Jinlin; Zhu, Ping; Liu, Wandong; Ti, Ang; Tokamak, Team Experimental Advanced Superconducting

doi:10.1063/1.4945751

Cited by 10 publications

(4 citation statements)

References 16 publications

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“…This example shows that the continuous and large field of view is large enough to cover the whole q = 1 surface. With this ECEI, the complete experimental observations of the compound sawteeth with high spatial and temporal evolutions have been reported in the literature [15].…”

Section: Implementation On the East Tokamakmentioning

confidence: 88%

The electron cyclotron emission imaging system on EAST with continuous large observation area

et al. 2018

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A: A 384 channels (24 vertical ×16 radial) Electron Cyclotron Emission Imaging (ECEI) system has been installed on Experimental Advanced Superconducting Tokamak (EAST). With the aid of advanced front optics, high spaital resolution around 1.1cm and flexible vertical coverage 30 ∼ 70 cm have been realized. The well-designed optics also provides a long Rayleigh length up to 70 cm even with an object length larger than 2.6 m. The electronic system has a wide immediate frequency (IF) bandwidth 2 ∼ 16.5 GHz, which enables a continuous radial coverage up to 25 cm. Benefited from advanced optics design and the wide IF bandwidth, the ECEI system with high spatial resolution can provide a large and continuous view field, especially in the radial direction, which is enough for the observation of the whole q = 1 surface. The comprehensive details of the ECEI system will be presented in this paper, along with some experimental results. K: Nuclear instruments and methods for hot plasma diagnostics; Plasma diagnosticsinterferometry, spectroscopy and imaging 1Corresponding author.

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Section: Implementation On the East Tokamakmentioning

confidence: 88%

The electron cyclotron emission imaging system on EAST with continuous large observation area

et al. 2018

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“…The signal lasts for ten seconds and ranges from -1 V to 1 V. The range is 0 V to 2 V if zero drift is processed. Typically, the range of saturated signals is from -1 V to 1 V, and the range of zero signals and weak signals is from 0 V to 2 V. By analyzing the electron temperature fluctuation (σT e ), sawtooth instability can be studied [13][14][15]. In general, there are three types of invalid data: saturated signals, zero signals, and weak signals.…”

Section: The Ecei Datamentioning

confidence: 99%

“…Typically, saturated signals range from −1 to 1 Volt, and zero signals and weak signals range from 0 to 2 Volt. By analyzing the electron temperature fluctuation (σT e ), the sawtooth instability can be studied [13][14][15]. In general, there are three types of invalid data: saturated signals, zero signals, and weak signals.…”

Section: The Ecei Datamentioning

confidence: 99%

An automatic data cleaning procedure for electron cyclotron emission imaging on EAST tokamak using machine learning algorithm

Lan

Wang

et al. 2018

J. Inst.

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A : A new data cleaning procedure for electron cyclotron emission imaging (ECEI) of EAST tokamak is developed. Machine learning techniques, including Support Vector Machine (SVM) and decision tree, are applied to identifying saturated, zero, and weak signals of ECEI raw data, which not only reduces the effort of researchers for data analysis, but also improves the accuracy of data preprocessing. Proper training sets are sampled using massive raw ECEI data from the EAST tokamak. Optimal window size of temporal signal, kernel function, and other model parameters are obtained by model training. With the optimized parameters, the recognition rates of saturated, zero, and weak signals in raw data are 99.4%, 99.86%, and 99.9%, respectively, which proves the accuracy of this procedure.

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“…ECEI systems were installed on the ASDEX-Upgrade, DIII-D, EAST, J-TEXT, and KSTAR tokamaks during the period 2010-2016 and represent the current state-of-the-art [2,[24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39]. Refinements to the optical design, new imaging array configurations, and the use of automated fabrication for improved reliability of low frequency components allowed the technique to probe new phenomena.…”

Section: Background: Technological and Physics Advancements For Ecei ...mentioning

confidence: 99%

Millimeter-wave imaging of magnetic fusion plasmas: technology innovations advancing physics understanding

Wang¹,

Tobias²,

Chang³

et al. 2017

Nucl. Fusion

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Electron cyclotron emission imaging (ECEI) passively collects spontaneous emission at harmonics of the cyclotron frequency, ω ce , and produces a 2D image of electron temperature, T e , for a poloidal cross-section of optically thick plasma [1][2][3][4][5][6]. It utilizes the fact that the cyclotron frequency in a tokamak depends on the major radius, leading to a 1:1 mapping between emission intensity and the local T e value. Along the poloidal direction, T e is imaged onto a vertically aligned array of antennas. Figure 1 illustrates both conventional 1DNuclear Fusion

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Observations of compound sawteeth in ion cyclotron resonant heating plasma using ECE imaging on experimental advanced superconducting tokamak

Cited by 10 publications

References 16 publications

The electron cyclotron emission imaging system on EAST with continuous large observation area

The electron cyclotron emission imaging system on EAST with continuous large observation area

An automatic data cleaning procedure for electron cyclotron emission imaging on EAST tokamak using machine learning algorithm

Millimeter-wave imaging of magnetic fusion plasmas: technology innovations advancing physics understanding

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