Optics design for Electron Cyclotron Emission Imaging system on J-TEXT

Ma, Xiaomeng; Zhang, Yang; Zhu, Yilun; Pan, Xiaolong; Xiao, Yao; Ruan, Bowen; Zhuang, G.; Xie, Jinlin

doi:10.1088/1748-0221/11/05/p05022

Cited by 10 publications

(3 citation statements)

References 14 publications

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“…Also, the distance between the focal optics and the zoom optics increased by 150 mm in the new design to ensure that the image plane can reach the high-field side of the plasma. The change of the radius of curvature from −1100 mm to −1000 mm and of the surface type from cylinder to Y toroid (conic constant −2.5) of the zoom 2 lens make the main contribution to improvement of the image surface shape compared with that of the present optics [15][16][17][18]. Finally, the radius of curvature of lens H1/H1′ was adjusted to ±800 mm from ±720 mm in order to make sure that the Xdirection beam radius on the image plane is less than 30 mm.…”

Section: Rf Opticsmentioning

confidence: 93%

Optimization of the optical system for electron cyclotron emission imaging diagnostics on the HL-2A tokamak

Jiang

Shi

Zhu

2017

Plasma Sci. Technol.

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The optical system of the electron cyclotron emission imaging diagnostics on the HL-2A tokamak has been optimized in both the narrow zoom pattern and the wide zoom pattern. The two main features of the improved optical system are (1) larger coverage of the measurement region in the plasma and (2) a flatter imaging surface. The new optics has good focal characteristics over the whole plasma cross section. The curvature of the field of the image surface (ΔR between the core channel and the edge channel) is within 5.3 cm in the narrow zoom pattern and 6.7 cm in the wide zoom pattern after optimization, whereas the values with the present optics were 23 cm in the narrow zoom pattern and 15 cm in the wide zoom pattern. The optics will be fabricated, tested and installed on the HL-2A tokamak before the next experimental campaign.

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Section: Rf Opticsmentioning

confidence: 93%

Optimization of the optical system for electron cyclotron emission imaging diagnostics on the HL-2A tokamak

Jiang

Shi

Zhu

2017

Plasma Sci. Technol.

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“…The measurement is made with 20 independent poloidal heterodyne receiver modules that down convert the ECE 2nd harmonic X mode radiation (∼100 GHz) to intermediate frequency (IF) signals. The front-end imaging optics are used to collect the emission signal and focus it onto the receiver module array [49][50][51][52]. Currently, the DIII-D ECEI optics serve to project the 20 receiver modules into parallel Gaussian beams in the plasma with around 15 mm poloidal beam waist radius.…”

Section: Instrumentation and Experimental Arrangementmentioning

confidence: 99%

Noise suppression for MHD characterization with electron cyclotron emission imaging 1D technique

Yu¹,

Kramer²,

Zhu³

et al. 2021

Plasma Phys. Control. Fusion

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Significant noise suppression for magnetohydrodynamics (MHD) mode characterization in the spatial and spectral domain is achieved by processing two-dimensional (2D) electron cyclotron emission imaging (ECEI) data with a one-dimensional (1D) ECEI technique using a short time window ( 1 ms ). The technique is applied to detect toroidal Alfven eigenmodes (TAEs) in the temporal spectrum and fit their radial envelope using the data from the DIII-D tokamak W-band 2D ECEI system. Using the data length (time window) of only 1 ms , the 1D ECEI can clearly detect the TAEs (∼100 kHz ) on the spectrum, while similar spectrum quality requires ∼10 ms data length with the cross power spectrum between two midplane ECEI channels. The 1D ECEI technique also effectively avoids biased fitting when resolving the fine structure of the TAE’s radial envelope. The radially spatial resolution of 1D ECEI is constrained by the finite ECE radiation volume of the ECEI receiver. With forward radiation modeling, we find the DIII-D ECEI system can sensitively measure the even parity MHD activities, for which the mode width is >15 mm, and tearing modes (odd parity MHD activities), for which the island full width is >30 mm.

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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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Optics design for Electron Cyclotron Emission Imaging system on J-TEXT

Abstract: Contents 1 Introduction 12 ECEI optics design on J-TEXT 3 2.1 Requirements for J-TEXT ECEI optics system 3 2.2 Optics system on J-TEXT 4 2.3 Performance analysis 6

Cited by 10 publications

References 14 publications

Optimization of the optical system for electron cyclotron emission imaging diagnostics on the HL-2A tokamak

Optimization of the optical system for electron cyclotron emission imaging diagnostics on the HL-2A tokamak

Noise suppression for MHD characterization with electron cyclotron emission imaging 1D technique

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

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