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Offeddu N, Wüthrich C, Han W, Theiler C, Golfinopoulos T, Terry JL, Marmar E, Galperti C, Andrebe Y, Duval BP, Bertizzolo R, Clement A, Février O, Elaian H, Gönczy D, Landis JD. Gas puff imaging on the TCV tokamak. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2022; 93:123504. [PMID: 36586925 DOI: 10.1063/5.0126398] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Accepted: 11/04/2022] [Indexed: 06/17/2023]
Abstract
We present the design and operation of a suite of Gas Puff Imaging (GPI) diagnostic systems installed on the Tokamak à Configuration Variable (TCV) for the study of turbulence in the plasma edge and Scrape-Off-Layer (SOL). These systems provide the unique ability to simultaneously collect poloidal 2D images of plasma dynamics at the outboard midplane, around the X-point, in both the High-Field Side (HFS) and Low-Field Side (LFS) SOL, and in the divertor region. We describe and characterize an innovative control system for deuterium and helium gas injection, which is becoming the default standard for the other gas injections at TCV. Extensive pre-design studies and the different detection systems are presented, including an array of avalanche photodiodes and a high-speed CMOS camera. First results with spatial and time resolutions of up to ≈2 mm and 0.5 µs, respectively, are described, and future upgrades of the GPI diagnostics for TCV are discussed.
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Affiliation(s)
- N Offeddu
- EPFL, Swiss Plasma Center (SPC), CH-1015 Lausanne, Switzerland
| | - C Wüthrich
- EPFL, Swiss Plasma Center (SPC), CH-1015 Lausanne, Switzerland
| | - W Han
- MIT, Plasma Science and Fusion Center (PSFC), Cambridge, Massachusetts 02139, USA
| | - C Theiler
- EPFL, Swiss Plasma Center (SPC), CH-1015 Lausanne, Switzerland
| | - T Golfinopoulos
- MIT, Plasma Science and Fusion Center (PSFC), Cambridge, Massachusetts 02139, USA
| | - J L Terry
- MIT, Plasma Science and Fusion Center (PSFC), Cambridge, Massachusetts 02139, USA
| | - E Marmar
- MIT, Plasma Science and Fusion Center (PSFC), Cambridge, Massachusetts 02139, USA
| | - C Galperti
- EPFL, Swiss Plasma Center (SPC), CH-1015 Lausanne, Switzerland
| | - Y Andrebe
- EPFL, Swiss Plasma Center (SPC), CH-1015 Lausanne, Switzerland
| | - B P Duval
- EPFL, Swiss Plasma Center (SPC), CH-1015 Lausanne, Switzerland
| | - R Bertizzolo
- EPFL, Swiss Plasma Center (SPC), CH-1015 Lausanne, Switzerland
| | - A Clement
- EPFL, Swiss Plasma Center (SPC), CH-1015 Lausanne, Switzerland
| | - O Février
- EPFL, Swiss Plasma Center (SPC), CH-1015 Lausanne, Switzerland
| | - H Elaian
- EPFL, Swiss Plasma Center (SPC), CH-1015 Lausanne, Switzerland
| | - D Gönczy
- EPFL, Swiss Plasma Center (SPC), CH-1015 Lausanne, Switzerland
| | - J D Landis
- EPFL, Swiss Plasma Center (SPC), CH-1015 Lausanne, Switzerland
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Liu S, Liao L, Zhong L, Wei W, Li L, Wei W, Yan N, Xing Y, Xu G, Shao L, Chen R, Hu G, Liu J, Liang Y, Han X, Cai J, Zhao N, Liu X, Ming T, Zang Q, Wang L, Zeng L, Li G, Gong X, Gao X. Upgrade and application of the gas puff imaging system in EAST. FUSION ENGINEERING AND DESIGN 2022. [DOI: 10.1016/j.fusengdes.2022.113156] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Yu Y, Xu M, Duan XR, Nie L, Ke R, Yuan BD, Gong SB, Lan T, Wang ZH, Long T, Wu YF, Yuan JB, Wu T, Chen YH, Liu H, Zhou YX, Wang HJ, Zhong WL, Shi ZB, Li JQ, Liu Y, Hao GZ, Chen W, Chen Q, Sun AP, Ye MY. Recent Progress of Optical and Spectroscopic Diagnostics for Turbulence on the HL-2A tokamak. JOURNAL OF FUSION ENERGY 2021. [DOI: 10.1007/s10894-021-00302-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Li F, Yang ZJ, Gao L, Fu CP. Development of the gas puffing imaging diagnostic on J-TEXT tokamak. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2021; 92:043503. [PMID: 34243373 DOI: 10.1063/5.0040988] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Accepted: 03/11/2021] [Indexed: 06/13/2023]
Abstract
Edge turbulence is important for plasma confinement, so the gas puffing imaging (GPI) diagnostic was proposed on the J-TEXT tokamak for the two-dimensional measurement of turbulence in the edge region. GPI is a diagnostic of plasma turbulence that uses a puff of neutral gas at the plasma edge to increase the local visible light emission for improved space-time resolution of plasma fluctuations. Considering the conditions of J-TEXT, the observation area is 21° away from the position of the optical system in the toroidal direction, and the observation area is 10 cm × 10 cm inside and outside the last closed flux surface. To have a lower divergence of the gas flow, the gas puff nozzle is specially designed. An interface has been developed for operation. To photograph the line radiation generated by the neutral gas cloud along the magnetic field lines, the optical system is designed. It is composed of a quartz glass, mirrors, commercial lenses, filters, and high-speed cameras. The high-speed camera can capture the line radiation with a speed up to 180 000 frames/s with 256 pixels × 256 pixels and an exposure time of 5 µs. In a recent experiment, the new GPI diagnostic has obtained some preliminary pictures.
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Affiliation(s)
- F Li
- International Joint Research Laboratory of Magnetic Confinement Fusion and Plasma Physics, State Key Laboratory of Advanced Electromagnetic Engineering and Technology, School of Electrical and Electronic Engineering, Huazhong University of Science and Technology, Wuhan 430074, Hubei, China
| | - Z J Yang
- International Joint Research Laboratory of Magnetic Confinement Fusion and Plasma Physics, State Key Laboratory of Advanced Electromagnetic Engineering and Technology, School of Electrical and Electronic Engineering, Huazhong University of Science and Technology, Wuhan 430074, Hubei, China
| | - L Gao
- International Joint Research Laboratory of Magnetic Confinement Fusion and Plasma Physics, State Key Laboratory of Advanced Electromagnetic Engineering and Technology, School of Electrical and Electronic Engineering, Huazhong University of Science and Technology, Wuhan 430074, Hubei, China
| | - C P Fu
- International Joint Research Laboratory of Magnetic Confinement Fusion and Plasma Physics, State Key Laboratory of Advanced Electromagnetic Engineering and Technology, School of Electrical and Electronic Engineering, Huazhong University of Science and Technology, Wuhan 430074, Hubei, China
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Buelo C, Stephey L, Anderson FSB, Eisert D, Anderson DT. Development of a 3-D visible limiter imaging system for the HSX stellarator. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2017; 88:123508. [PMID: 29289158 DOI: 10.1063/1.5000855] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
A visible camera diagnostic has been developed to study the Helically Symmetric eXperiment (HSX) limiter plasma interaction. A straight line view from the camera location to the limiter was not possible due to the complex 3D stellarator geometry of HSX, so it was necessary to insert a mirror/lens system into the plasma edge. A custom support structure for this optical system tailored to the HSX geometry was designed and installed. This system holds the optics tube assembly at the required angle for the desired view to both minimize system stress and facilitate robust and repeatable camera positioning. The camera system has been absolutely calibrated and using Hα and C-III filters can provide hydrogen and carbon photon fluxes, which through an S/XB coefficient can be converted into particle fluxes. The resulting measurements have been used to obtain the characteristic penetration length of hydrogen and C-III species. The hydrogen λiz value shows reasonable agreement with the value predicted by a 1D penetration length calculation.
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Affiliation(s)
- C Buelo
- University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - L Stephey
- University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - F S B Anderson
- University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - D Eisert
- University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - D T Anderson
- University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
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Zweben SJ, Terry JL, Stotler DP, Maqueda RJ. Invited Review Article: Gas puff imaging diagnostics of edge plasma turbulence in magnetic fusion devices. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2017; 88:041101. [PMID: 28456269 DOI: 10.1063/1.4981873] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Gas puff imaging (GPI) is a diagnostic of plasma turbulence which uses a puff of neutral gas at the plasma edge to increase the local visible light emission for improved space-time resolution of plasma fluctuations. This paper reviews gas puff imaging diagnostics of edge plasma turbulence in magnetic fusion research, with a focus on the instrumentation, diagnostic cross-checks, and interpretation issues. The gas puff imaging hardware, optics, and detectors are described for about 10 GPI systems implemented over the past ∼15 years. Comparison of GPI results with other edge turbulence diagnostic results is described, and many common features are observed. Several issues in the interpretation of GPI measurements are discussed, and potential improvements in hardware and modeling are suggested.
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Affiliation(s)
- S J Zweben
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08540, USA
| | - J L Terry
- MIT, Cambridge, Massachusetts 02139, USA
| | - D P Stotler
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08540, USA
| | - R J Maqueda
- X Science LLC, Plainsboro, New Jersey 08536, USA
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Sierchio JM, Cziegler I, Terry JL, White AE, Zweben SJ. Comparison of velocimetry techniques for turbulent structures in gas-puff imaging data. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2016; 87:023502. [PMID: 26931844 DOI: 10.1063/1.4939672] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Recent analysis of Gas Puff Imaging (GPI) data from Alcator C-Mod found blob velocities with a modified tracking time delay estimation (TDE). These results disagree with velocity analysis performed using direct Fourier methods. In this paper, the two analysis methods are compared. The implementations of these methods are explained, and direct comparisons using the same GPI data sets are presented to highlight the discrepancies in measured velocities. In order to understand the discrepancies, we present a code that generates synthetic sequences of images that mimic features of the experimental GPI images, with user-specified input values for structure (blob) size and velocity. This allows quantitative comparison of the TDE and Fourier analysis methods, which reveals their strengths and weaknesses. We found that the methods agree for structures of any size as long as all structures move at the same velocity and disagree when there is significant nonlinear dispersion or when structures appear to move in opposite directions. Direct Fourier methods used to extract poloidal velocities give incorrect results when there is a significant radial velocity component and are subject to the barber pole effect. Tracking TDE techniques give incorrect velocity measurements when there are features moving at significantly different speeds or in different directions within the same field of view. Finally, we discuss the limitations and appropriate use of each of methods and applications to the relationship between blob size and velocity.
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Affiliation(s)
- J M Sierchio
- Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - I Cziegler
- Center for Momentum Transport and Flow Organization, University of California, San Diego, La Jolla, California 92093, USA
| | - J L Terry
- Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - A E White
- Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - S J Zweben
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA
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Davis W, Ko M, Maqueda R, Roquemore A, Scotti F, Zweben S. Fast 2-D camera control, data acquisition, and database techniques for edge studies on NSTX. FUSION ENGINEERING AND DESIGN 2014. [DOI: 10.1016/j.fusengdes.2013.11.014] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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