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Banerjee S, Boyle DP, Maan A, Majeski R, Kaita R, Smith D, von Hellermann M, Hansen C, Capecchi W, Elliott D. Feasibility study of a high spatial and time resolution beam emission spectroscopy diagnostic for localized density fluctuation measurements in Lithium Tokamak eXperiment-β (LTX-β). THE REVIEW OF SCIENTIFIC INSTRUMENTS 2022; 93:113523. [PMID: 36461475 DOI: 10.1063/5.0101834] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Accepted: 09/28/2022] [Indexed: 06/17/2023]
Abstract
Trapped electron mode (TEM) is the main source of turbulence predicted for the unique operation regime of a flat temperature profile under low-recycling conditions in the LTX-β tokamak, while ion temperature gradient driven turbulence may also occur with gas fueling from the edge. To investigate mainly TEM scale density fluctuations, a high spatial and time resolution 2D beam emission spectroscopy (BES) diagnostic is being developed. Apart from spatially localized density turbulence measurement, BES can provide turbulence flow and flow shear dynamics. This BES system will be realized using an avalanche photodiode-based camera and narrow band interference filter. The system can acquire data at 2 MHz. Simulations with the Simulation of Spectra (SOS) code indicate that a high signal to noise ratio can be achieved with the proposed system. This will enable sampling the density fluctuations at this high time resolution. The design considerations and system optimization using the SOS code are presented.
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Affiliation(s)
- Santanu Banerjee
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08540, USA
| | - D P Boyle
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08540, USA
| | - A Maan
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08540, USA
| | - R Majeski
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08540, USA
| | - R Kaita
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08540, USA
| | - D Smith
- Department of Physics, University of Wisconsin, Madison, Wisconsin 53706, USA
| | - M von Hellermann
- Institute for Energy and Climate Research IEK-4, Forschungszentrum Jülich GmbH, 52425 Jülich, Germany
| | - C Hansen
- Department of Aeronautics and Astronautics, University of Washington, Seattle, Washington 98195, USA
| | - W Capecchi
- Department of Physics, University of Wisconsin, Madison, Wisconsin 53706, USA
| | - D Elliott
- Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830, USA
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Qin X, McKee G, Yan Z, Geiger B, Ke R, Jaehnig K, Morton L, Wu Y, Wu T, Xu M. Integrated 2D beam emission spectroscopy diagnostic at the Huan-Liuqi-2A (HL-2A) tokamak. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2022; 93:103535. [PMID: 36319390 DOI: 10.1063/5.0101806] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Accepted: 09/09/2022] [Indexed: 06/16/2023]
Abstract
Two newly developed, eight-channel, integrated Beam Emission Spectroscopy (BES) detectors have been installed at Huan-Liuqi-2A tokamak, which extends the existing 16 single-channel modular BES system with additional 16 spatial channels. The BES collects the Doppler-shifted Balmer Dα emission with a spatial resolution of 1 cm (radial) × 1.5 cm (poloidal) and a temporal resolution of 0.5 µs to measure long-wavelength (k⊥ρi < 1) density fluctuations. Compared to the modular BES, the dark noise of the integrated BES is reduced by 50%-60% on average. The signal-to-noise ratio of the integrated BES system is optimized by the high light throughput front-end optics, high quantum efficiency photodiodes, high-gain, low-noise preamplifiers, and sufficient cooling capacity provided by the thermoelectric cooling (TEC) units that maintain the detectors at -20 °C. Crosstalk between channels that share the same optical system is found to be negligible. High-quality density fluctuation data enables 2D (radial-poloidal) imaging of turbulence, which allows for multi-channel spectral analysis, multi-channel cross-correlation analysis and velocimetry analysis. Preliminary results show that BES successfully captures the spatiotemporal features of the local turbulence and obtains statistically consistent turbulence characterization results.
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Affiliation(s)
- X Qin
- Engineering Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - G McKee
- Engineering Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - Z Yan
- Engineering Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - B Geiger
- Engineering Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - R Ke
- Southwestern Institute of Physics, Chengdu, Sichuan 610000, China
| | - K Jaehnig
- Engineering Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - L Morton
- Engineering Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - Y Wu
- Southwestern Institute of Physics, Chengdu, Sichuan 610000, China
| | - T Wu
- Southwestern Institute of Physics, Chengdu, Sichuan 610000, China
| | - M Xu
- Southwestern Institute of Physics, Chengdu, Sichuan 610000, China
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Smith DR, McKee G, Den Hartog D, Geiger B, Grulke O, Han X, Jaehnig K, Seyfert C, Windisch T. Conceptual design and performance predictions for 2D beam emission spectroscopy turbulence measurements at Wendelstein 7-X. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2022; 93:073506. [PMID: 35922327 DOI: 10.1063/5.0101355] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Accepted: 06/27/2022] [Indexed: 06/15/2023]
Abstract
A conceptual design for a 2D beam emission spectroscopy diagnostic system to measure ion gyro-scale plasma turbulence at Wendeslstein 7-X is described. The conceptual design identifies field-aligned viewing geometries and ports for cross-field turbulence measurements in the neutral beam volume. A 2D sightline grid covers the outer plasma region, and the grid configuration provides sufficient k-space coverage in radial and poloidal directions for ion temperature gradient and trapped-electron mode turbulence measurements. Emission intensity estimates, optical transmission losses, and detector noise levels indicate that the measurements will be sensitive to plasma density fluctuations as small as δn/n ≈ 0.5% with a bandwidth of 1 MHz. Implementation challenges include a small beam emission Doppler shift due to nearly radial heating beams and reduced optical throughput due to collection aperture limitations.
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Affiliation(s)
- D R Smith
- University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - G McKee
- University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - D Den Hartog
- University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - B Geiger
- University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - O Grulke
- Max Planck Institute for Plasma Physics, 17491 Greifswald, Germany
| | - X Han
- University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - K Jaehnig
- University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - C Seyfert
- University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - T Windisch
- Max Planck Institute for Plasma Physics, 17491 Greifswald, Germany
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Zhou Y, Yu Y, Ke R, Jiang W, Xu M, Xiao C, Cheng Y, Li Z, Li B, Wang Z, Li J, Duan X, Ye M. Design of a Lyman-Alpha-Based BES for edge plasma density diagnosing on the HL-2A tokamak. FUSION ENGINEERING AND DESIGN 2021. [DOI: 10.1016/j.fusengdes.2021.112911] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Yuan BD, Yu Y, He RC, Yang XY, Xu TC, Yuan JB, Hong RJ, Nie L, Ke R, Long T, Wang ZH, Xiao CJ, Xu M, Li JQ, Ye MY, Duan XR. Development of a multi-color gas puff imaging diagnostic on HL-2A tokamak. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2020; 91:073505. [PMID: 32752858 DOI: 10.1063/5.0005545] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Accepted: 07/02/2020] [Indexed: 06/11/2023]
Abstract
A Multi-Color (MC) gas puff imaging diagnostic has been developed on HL-2A tokamak. This diagnostic can simultaneously measure two-dimensional (2D, radial, and poloidal) electron density and temperature distributions with a good spatial resolution of 2.5 × 2.5 mm2 and a temporal resolution of about 100 µs at best in edge plasmas. The 2D electron density and temperature distributions are inferred from the ratios of intensities of three different neutral helium emission lines; therefore, it is also referred to as helium beam probe or beam emission spectroscopy on thermal helium. A compact light splitter is used to split the inlet visible emission beam into four channels, and the specific neutral helium lines of the wavelengths λ1 = 587.6 nm, λ2 = 667.8 nm, λ3 = 706.5 nm, and λ4 = 728.1 nm are measured, respectively. This MC diagnostic has been experimentally tested and calibrated on a linear magnetic confinement device Peking University Plasma Test device, and the measured 2D electron density and temperature distributions are compared with the Langmuir probe measurements.
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Affiliation(s)
- B D Yuan
- School of Physics, University of Science and Technology of China, Hefei 230026, China
| | - Y Yu
- School of Physics, University of Science and Technology of China, Hefei 230026, China
| | - R C He
- School of Physics, Peking University, Beijing 100871, China
| | - X Y Yang
- School of Physics, Peking University, Beijing 100871, China
| | - T C Xu
- School of Physics, Peking University, Beijing 100871, China
| | - J B Yuan
- Southwestern Institute of Physics, Chengdu 610041, China
| | - R J Hong
- Physics and Astronomy Department, University of California, Los Angeles, California 90095, USA
| | - L Nie
- Southwestern Institute of Physics, Chengdu 610041, China
| | - R Ke
- Southwestern Institute of Physics, Chengdu 610041, China
| | - T Long
- Southwestern Institute of Physics, Chengdu 610041, China
| | - Z H Wang
- Southwestern Institute of Physics, Chengdu 610041, China
| | - C J Xiao
- School of Physics, Peking University, Beijing 100871, China
| | - M Xu
- Southwestern Institute of Physics, Chengdu 610041, China
| | - J Q Li
- Southwestern Institute of Physics, Chengdu 610041, China
| | - M Y Ye
- School of Physics, University of Science and Technology of China, Hefei 230026, China
| | - X R Duan
- Southwestern Institute of Physics, Chengdu 610041, China
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