1
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Terry JL, von Stechow A, Baek SG, Ballinger SB, Grulke O, von Sehren C, Laube R, Killer C, Scharmer F, Brunner KJ, Knauer J, Bois S. Realization of a gas puff imaging system on the Wendelstein 7-X stellarator. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2024; 95:093517. [PMID: 39254433 DOI: 10.1063/5.0219336] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2024] [Accepted: 08/12/2024] [Indexed: 09/11/2024]
Abstract
A system for studying the spatiotemporal dynamics of fluctuations in the boundary of the W7-X plasma using the "Gas-Puff Imaging" (GPI) technique has been designed, constructed, installed, and operated. This GPI system addresses a number of challenges specific to long-pulse superconducting devices, such as W7-X, including the long distance between the plasma and the vacuum vessel wall, the long distance between the plasma and diagnostic ports, the range of last closed flux surface (LCFS) locations for different magnetic configurations in W7-X, and management of heat loads on the system's plasma-facing components. The system features a pair of "converging-diverging" nozzles for partially collimating the gas puffed locally ≈135 mm radially outboard of the plasma boundary, a pop-up turning mirror for viewing the gas puff emission from the side (which also acts as a shutter for the re-entrant vacuum window), and a high-throughput optical system that collects visible emission resulting from the interaction between the puffed gas and the plasma and directs it along a water-cooled re-entrant tube directly onto the 8 × 16 pixel detector array of the fast camera. The DEGAS 2 neutral code was used to simulate the Hα (656 nm) and HeI (587 nm) line emission expected from well-characterized gas-puffs of H2 and He and excited within typical edge plasma profiles in W7-X, thereby predicting line brightnesses used to reduce the risks associated with system sensitivity and placement of the field of view. Operation of GPI on W7-X shows excellent signal-to-noise ratios (>100 at 2 Mframes/s) over the field of view for minimally perturbing gas puffs. The GPI system provides detailed measurements of the two-dimensional (radial and poloidal) dynamics of plasma fluctuations in the W7-X edge and scrape-off layer and in and around the magnetic islands outside the LCFS that make up the island divertor configuration employed on W7-X.
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Affiliation(s)
- J L Terry
- Massachusetts Institute of Technology - Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA
| | - A von Stechow
- Max-Planck-Institut für Plasmaphysik, Wendelsteinstraße 1, 17491 Greifswald, Germany
| | - S G Baek
- Massachusetts Institute of Technology - Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA
| | - S B Ballinger
- Massachusetts Institute of Technology - Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA
| | - O Grulke
- Max-Planck-Institut für Plasmaphysik, Wendelsteinstraße 1, 17491 Greifswald, Germany
| | - C von Sehren
- Max-Planck-Institut für Plasmaphysik, Wendelsteinstraße 1, 17491 Greifswald, Germany
| | - R Laube
- Max-Planck-Institut für Plasmaphysik, Wendelsteinstraße 1, 17491 Greifswald, Germany
| | - C Killer
- Max-Planck-Institut für Plasmaphysik, Wendelsteinstraße 1, 17491 Greifswald, Germany
| | - F Scharmer
- Max-Planck-Institut für Plasmaphysik, Wendelsteinstraße 1, 17491 Greifswald, Germany
| | - K J Brunner
- Max-Planck-Institut für Plasmaphysik, Wendelsteinstraße 1, 17491 Greifswald, Germany
| | - J Knauer
- Max-Planck-Institut für Plasmaphysik, Wendelsteinstraße 1, 17491 Greifswald, Germany
| | - S Bois
- Laboratoire de Physique des Plasmas, Ecole Polytechnique-CNRS-Univ Paris-Sud-UPMC, Rte de Saclay, 91128 Palaiseau, France
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2
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Lampert M, Anda G, Asztalos O, Berkery JW, Diallo A, Stratton B, Zoletnik S. Applicability of alkali beam emission spectroscopy on NSTX-U. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2024; 95:093538. [PMID: 39324764 DOI: 10.1063/5.0218248] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2024] [Accepted: 08/14/2024] [Indexed: 09/27/2024]
Abstract
Understanding fast pedestal dynamics and turbulent transport in the edge and scrape-off layer (SOL) plasma of spherical tokamaks is crucial for the design and operation of future fusion reactors. The alkali beam emission spectroscopy diagnostic technique offers a means to measure the absolute electron density radial profile and fluctuation amplitude in these regions. In this study, we demonstrate that injecting a sodium neutral beam radially into the plasma and analyzing the light emission from its 3p-3s atomic transition using near-orthogonal viewing angles allows for accurate measurement of the electron density profile and fluctuations in the National Spherical Torus Experiment (NSTX) Upgrade spherical tokamak. Our findings indicate a peak signal-to-noise ratio of 118 in the pedestal and 12 in the SOL under typical NSTX plasma conditions. The spatial resolution for the electron density profile is estimated to be between 2 and 8 mm, while for fluctuation measurements, it ranges from 12 to 15 mm.
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Affiliation(s)
- M Lampert
- Princeton Plasma Physics Laboratory, Princeton, New Jersey, USA
| | - G Anda
- HUN-REN Centre for Energy Research, Budapest, Hungary
| | - O Asztalos
- HUN-REN Centre for Energy Research, Budapest, Hungary
- Budapest University of Technology and Economics, Budapest, Hungary
| | - J W Berkery
- Princeton Plasma Physics Laboratory, Princeton, New Jersey, USA
| | - A Diallo
- Princeton Plasma Physics Laboratory, Princeton, New Jersey, USA
| | - B Stratton
- Princeton Plasma Physics Laboratory, Princeton, New Jersey, USA
| | - S Zoletnik
- HUN-REN Centre for Energy Research, Budapest, Hungary
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3
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Balazs P, Asztalos O, Anda G, Vecsei M, Zoletnik S, Kumar S, Pokol G. Special behavior of alkali beam emission spectroscopy in low-ion-temperature plasma. FUSION ENGINEERING AND DESIGN 2023. [DOI: 10.1016/j.fusengdes.2023.113650] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/03/2023]
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4
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Vécsei M, Anda G, Asztalos O, Dunai D, Hegedűs S, Nagy D, Otte M, Pokol GI, Zoletnik S. Swift evaluation of electron density profiles obtained by the alkali beam emission spectroscopy technique using linearized reconstruction. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2021; 92:113501. [PMID: 34852513 DOI: 10.1063/5.0057158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Accepted: 10/22/2021] [Indexed: 06/13/2023]
Abstract
A method is presented for the swift reconstruction of electron density profiles measured by the alkali beam emission spectroscopy. It is based on the linearization of the governing rate equations and leads to a direct calculation for obtaining the profiles. The uncertainties of the measurement are incorporated into the problem through the utilization of Tikhonov regularization and the generalized least squares method. An approximation for the uncertainty of the reconstructed density data is calculated as well. The applicability of the method is tested against both simulated and real experimental results of the W7-X stellarator.
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Affiliation(s)
- M Vécsei
- Centre for Energy Research, Konkoly-Thege Miklós út 29-33, 1121 Budapest, Hungary
| | - G Anda
- Centre for Energy Research, Konkoly-Thege Miklós út 29-33, 1121 Budapest, Hungary
| | - O Asztalos
- Centre for Energy Research, Konkoly-Thege Miklós út 29-33, 1121 Budapest, Hungary
| | - D Dunai
- Centre for Energy Research, Konkoly-Thege Miklós út 29-33, 1121 Budapest, Hungary
| | - S Hegedűs
- Centre for Energy Research, Konkoly-Thege Miklós út 29-33, 1121 Budapest, Hungary
| | - D Nagy
- Centre for Energy Research, Konkoly-Thege Miklós út 29-33, 1121 Budapest, Hungary
| | - M Otte
- Max-Planck Institute for Plasma Physics, Wendelsteinstrasse 1, 17491 Greifswald, Germany
| | - G I Pokol
- Centre for Energy Research, Konkoly-Thege Miklós út 29-33, 1121 Budapest, Hungary
| | - S Zoletnik
- Centre for Energy Research, Konkoly-Thege Miklós út 29-33, 1121 Budapest, Hungary
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5
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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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6
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Li Q, Cheng Z, Zhang X, Zhang X, Jiao S, Qing W, Chen Z. Design of fast response Doppler spectroscopy system for HUST field-reversed configuration device. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2021; 92:063522. [PMID: 34243503 DOI: 10.1063/5.0043310] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Accepted: 06/08/2021] [Indexed: 06/13/2023]
Abstract
A fast response Doppler spectroscopy system with high throughput and high resolution is under development for studying the drifting velocity, rotation velocity, and ion temperature on the HUST field-reversed configuration (HFRC) device. The system has been designed to observe the spectral line of oxygen V (O V) ion emission at 278.1 nm (1s22s3p → 1s22s3s) over the lifetime (∼0.5 ms) of the FRC plasma. A high throughput Czerny-Turner monochromator with 3600 g/mm grating and 670 mm focal length is applied to achieve high spectral resolution; a 32-channel multi-anode photomultiplier tube (PMT) detector is utilized to achieve the high-speed response of up to 1 MHz; a 1D magnification optics combined with a cylindrical lens assembly and a fiber optic expansion is developed to magnify the spectral dispersion fitting the PMT channel interval. Through the ray-tracing analysis, the system's final spectral resolution is evaluated to be ∼0.03 nm. Taking into account the system sensitivity and O V line emissivity in HFRC plasma, the system is expected to be workable with the temporal response of 1 µs.
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Affiliation(s)
- Qiong 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, China
| | - Zhifeng Cheng
- 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, China
| | - Xiaolong Zhang
- Advanced Energy Research Center, Shenzhen University, Shenzhen 518060, People's Republic of China
| | - XiaoYi Zhang
- 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, China
| | - Shaodong Jiao
- 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, China
| | - Wanjun Qing
- 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, China
| | - Zhipeng Chen
- 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, China
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7
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Gonzalez-Martin J, Garcia-Munoz M, Sieglin B, Herrmann A, Lunt T, Ayllon-Guerola J, Galdon-Quiroga J, Hidalgo-Salaverri J, Kovacsik A, Rivero-Rodriguez JF, Sanchis L, Silvagni D, Zoletnik S, Dominguez J. Self-adaptive diagnostic of radial fast-ion loss measurements on the ASDEX Upgrade tokamak (invited). THE REVIEW OF SCIENTIFIC INSTRUMENTS 2021; 92:053538. [PMID: 34243326 DOI: 10.1063/5.0043756] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Accepted: 04/28/2021] [Indexed: 06/13/2023]
Abstract
A poloidal array of scintillator-based Fast-Ion Loss Detectors (FILDs) has been installed in the ASDEX Upgrade (AUG) tokamak. While all AUG FILD systems are mounted on reciprocating arms driven externally by servomotors, the reciprocating system of the FILD probe located just below the midplane is based on a magnetic coil that is energized in real-time by the AUG discharge control system. This novel reciprocating system allows, for the first time, real-time control of the FILD position including infrared measurements of its probe head temperature to avoid overheating. This considerably expands the diagnostic operational window, enabling unprecedented radial measurements of fast-ion losses. Fast collimator-slit sweeping (up to 0.2 mm/ms) is used to obtain radially resolved velocity-space measurements along 8 cm within the scrape-off layer. This provides a direct evaluation of the neutral beam deposition profiles via first-orbit losses. Moreover, the light-ion beam probe (LIBP) technique is used to infer radial profiles of fast-ion orbit deflection. This radial-LIBP technique is applied to trapped orbits (exploring both the plasma core and the FILD stroke near the wall), enabling radial localization of internal plasma fluctuations (neoclassical tearing modes). This is quantitatively compared against electron cyclotron emission measurements, showing excellent agreement. For the first time, radial profiles of fast-ion losses in MHD quiescent plasmas as well as in the presence of magnetic islands and edge localized modes are presented.
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Affiliation(s)
- J Gonzalez-Martin
- Department of Mechanical Engineering and Manufacturing, Universidad de Sevilla, 41092 Sevilla, Spain
| | - M Garcia-Munoz
- Centro Nacional de Aceleradores (CNA), 41092 Sevilla, Spain
| | - B Sieglin
- Max Planck Institute for Plasma Physics, 85748 Garching, Germany
| | - A Herrmann
- Max Planck Institute for Plasma Physics, 85748 Garching, Germany
| | - T Lunt
- Max Planck Institute for Plasma Physics, 85748 Garching, Germany
| | - J Ayllon-Guerola
- Department of Mechanical Engineering and Manufacturing, Universidad de Sevilla, 41092 Sevilla, Spain
| | - J Galdon-Quiroga
- Department of Atomic, Molecular and Nuclear Physics, Universidad de Sevilla, 41012 Sevilla, Spain
| | - J Hidalgo-Salaverri
- Department of Mechanical Engineering and Manufacturing, Universidad de Sevilla, 41092 Sevilla, Spain
| | - A Kovacsik
- Budapest University of Technology and Economics, 1111 Budapest, Hungary
| | - J F Rivero-Rodriguez
- Department of Mechanical Engineering and Manufacturing, Universidad de Sevilla, 41092 Sevilla, Spain
| | - L Sanchis
- Department of Applied Physics, Aalto University, FI-00076 Aalto, Finland
| | - D Silvagni
- Max Planck Institute for Plasma Physics, 85748 Garching, Germany
| | | | - J Dominguez
- Department of Mechanical Engineering and Manufacturing, Universidad de Sevilla, 41092 Sevilla, Spain
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8
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Li Y, Zhou Y, Jiang D, Zhou X, Yu Y, Fu J, Lyu B, Shi Y, Xu G, Ye M, Wan B. Concept design of ultrafast charge exchange recombination spectroscopy on EAST tokamak. FUSION ENGINEERING AND DESIGN 2019. [DOI: 10.1016/j.fusengdes.2019.01.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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9
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Liao KT, Austin ME, Rowan WL, Thomas DM, Zhao BZ. Estimating the performance of lithium beam measurements of current density and electron density in an H-mode pedestal. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2018; 89:10D135. [PMID: 30399706 DOI: 10.1063/1.5035294] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Accepted: 06/22/2018] [Indexed: 06/08/2023]
Abstract
The lithium beam is an effective diagnostic tool for investigation of stability and particle transport in the pedestal. It was used successfully to measure edge current density on DIII-D, achieving qualitative agreement with neoclassical models. Electron density profiles were also measured. Proposed upgrades will continue these measurements with higher reliability as well as explore edge current measurements using spectroscopy. The optics will be redesigned to optimize throughput and aperture broadening and to replace the photomultiplier tubes with avalanche photodiodes. The new system will yield detailed measurements of the pedestal, complementing existing diagnostics for investigating pedestal stability, edge localized mode cycle, and particle transport through the pedestal.
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Affiliation(s)
- K T Liao
- Institute for Fusion Studies, University of Texas at Austin, Austin, Texas 78702, USA
| | - M E Austin
- Institute for Fusion Studies, University of Texas at Austin, Austin, Texas 78702, USA
| | - W L Rowan
- Institute for Fusion Studies, University of Texas at Austin, Austin, Texas 78702, USA
| | - D M Thomas
- General Atomics, San Diego, California 92186, USA
| | - B Z Zhao
- Institute for Fusion Studies, University of Texas at Austin, Austin, Texas 78702, USA
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10
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Griener M, Wolfrum E, Cavedon M, Dux R, Rohde V, Sochor M, Muñoz Burgos JM, Schmitz O, Stroth U. Helium line ratio spectroscopy for high spatiotemporal resolution plasma edge profile measurements at ASDEX Upgrade (invited). THE REVIEW OF SCIENTIFIC INSTRUMENTS 2018; 89:10D102. [PMID: 30399953 DOI: 10.1063/1.5034446] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The thermal helium beam edge diagnostic has recently been upgraded at the ASDEX Upgrade (AUG) tokamak experiment. Line ratio spectroscopy on neutral helium is a valuable tool for simultaneous determination of the electron temperature and density of plasmas. The diagnostic now offers a temporal resolution of 900 kHz with a spatial resolution of up to 3 mm at 32 lines of sight (LOS) simultaneously. The LOS covers a radial region of 8.5 cm, starting at the limiter radius and reaching into the confined region beyond the separatrix. Two components are of particular importance for the aforementioned hardware improvements. The first is the optical head, which collects the light from the experiment. Equipped with an innovative clamping system for optical fiber ends, an arbitrary distribution pattern of LOS can be achieved to gain radial and poloidal profiles. The second major development is a new polychromator system that measures the intensity of the 587 nm, 667 nm, 706 nm, and 728 nm helium lines simultaneously for 32 channels with filter-photomultiplier tube arrays. Thus, the thermal helium beam diagnostic supplements the AUG edge diagnostics, offering fast and spatially highly resolved electron temperature and density profile measurements that cover the plasma edge and scrape-off layer region. Plasma fluctuations, edge localized modes, filaments, and other turbulent structures are resolved, allowing analysis of their frequency and localization or their propagation velocity.
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Affiliation(s)
- M Griener
- Max Planck Institute for Plasma Physics, Boltzmannstr. 2, 85748 Garching, Germany
| | - E Wolfrum
- Max Planck Institute for Plasma Physics, Boltzmannstr. 2, 85748 Garching, Germany
| | - M Cavedon
- Max Planck Institute for Plasma Physics, Boltzmannstr. 2, 85748 Garching, Germany
| | - R Dux
- Max Planck Institute for Plasma Physics, Boltzmannstr. 2, 85748 Garching, Germany
| | - V Rohde
- Max Planck Institute for Plasma Physics, Boltzmannstr. 2, 85748 Garching, Germany
| | - M Sochor
- Max Planck Institute for Plasma Physics, Boltzmannstr. 2, 85748 Garching, Germany
| | - J M Muñoz Burgos
- Astro Fusion Spectre, LLC, 11263 Avenida de los Lobos, Unit D, San Diego, California 92127, USA
| | - O Schmitz
- Department of Engineering Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - U Stroth
- Max Planck Institute for Plasma Physics, Boltzmannstr. 2, 85748 Garching, Germany
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11
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Rivero-Rodriguez JF, Garcia-Munoz M, Martin R, Galdon-Quiroga J, Ayllon-Guerola J, Akers RJ, Buchanan J, Croft D, Garcia-Vallejo D, Gonzalez-Martin J, Harvey D, McClements KG, Rodriguez-Ramos M, Sanchis L. A rotary and reciprocating scintillator based fast-ion loss detector for the MAST-U tokamak. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2018; 89:10I112. [PMID: 30399654 DOI: 10.1063/1.5039311] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Accepted: 06/11/2018] [Indexed: 06/08/2023]
Abstract
The design and unique feature of the first fast-ion loss detector (FILD) for the Mega Amp Spherical Tokamak - Upgrade (MAST-U) is presented here. The MAST-U FILD head is mounted on an axially and angularly actuated mechanism that makes it possible to independently adapt the orientation [0°, 90°] and radial position [1.40 m, 1.60 m] of the FILD head, i.e., its collimator, thus maximizing the detector velocity-space coverage in a broad range of plasma scenarios with different q95. The 3D geometry of the detector has been optimized to detect fast-ion losses from the neutral beam injectors. Orbit simulations are used to calculate the strike map and predict the expected signals. The results show a velocity-space range of [4 cm, 13 cm] in gyroradius and [30°, 85°] in pitch angle, covering the entire neutral beam ion energy range. The optical system will provide direct sight of the scintillator and simultaneous detection with two cameras, giving high spatial and temporal resolution. The MAST-U FILD will shed light on the dominant fast-ion transport mechanisms in one of the world's two largest spherical tokamaks through absolute measurements of fast-ion losses.
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Affiliation(s)
- J F Rivero-Rodriguez
- Department of Mechanical Engineering and Manufacturing, University of Seville, Camino de los Descubrimientos s/n, 41092 Seville, Spain
| | - M Garcia-Munoz
- Centro Nacional de Aceleradores (CNA), Universidad de Sevilla, CSIC, Junta de Andalucia, Seville, Spain
| | - R Martin
- CCFE, Culham Science Centre, Abingdon, Oxon OX14 3DB, United Kingdom
| | - J Galdon-Quiroga
- Centro Nacional de Aceleradores (CNA), Universidad de Sevilla, CSIC, Junta de Andalucia, Seville, Spain
| | - J Ayllon-Guerola
- Department of Mechanical Engineering and Manufacturing, University of Seville, Camino de los Descubrimientos s/n, 41092 Seville, Spain
| | - R J Akers
- CCFE, Culham Science Centre, Abingdon, Oxon OX14 3DB, United Kingdom
| | - J Buchanan
- CCFE, Culham Science Centre, Abingdon, Oxon OX14 3DB, United Kingdom
| | - D Croft
- CCFE, Culham Science Centre, Abingdon, Oxon OX14 3DB, United Kingdom
| | - D Garcia-Vallejo
- Department of Mechanical Engineering and Manufacturing, University of Seville, Camino de los Descubrimientos s/n, 41092 Seville, Spain
| | - J Gonzalez-Martin
- Department of Mechanical Engineering and Manufacturing, University of Seville, Camino de los Descubrimientos s/n, 41092 Seville, Spain
| | - D Harvey
- CCFE, Culham Science Centre, Abingdon, Oxon OX14 3DB, United Kingdom
| | - K G McClements
- CCFE, Culham Science Centre, Abingdon, Oxon OX14 3DB, United Kingdom
| | - M Rodriguez-Ramos
- Centro Nacional de Aceleradores (CNA), Universidad de Sevilla, CSIC, Junta de Andalucia, Seville, Spain
| | - L Sanchis
- Centro Nacional de Aceleradores (CNA), Universidad de Sevilla, CSIC, Junta de Andalucia, Seville, Spain
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12
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Gonzalez-Martin J, Ayllon-Guerola J, Garcia-Munoz M, Herrmann A, Leitenstern P, De Marne P, Zoletnik S, Kovacsik A, Galdon-Quiroga J, Rivero-Rodriguez J, Rodriguez-Ramos M, Sanchis-Sanchez L, Dominguez J. First measurements of a scintillator based fast-ion loss detector near the ASDEX Upgrade divertor. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2018; 89:10I106. [PMID: 30399966 DOI: 10.1063/1.5038968] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Accepted: 06/03/2018] [Indexed: 06/08/2023]
Abstract
A new reciprocating scintillator based fast-ion loss detector has been installed a few centimeters above the outer divertor of the ASDEX Upgrade tokamak and between two of its lower Edge Localized Modes (ELM) mitigation coils. The detector head containing the scintillator screen, Faraday cup, calibration lamp, and collimator systems are installed on a motorized reciprocating system that can adjust its position via remote control in between plasma discharges. Orbit simulations are used to optimize the detector geometry and velocity-space coverage. The scintillator image is transferred to the light acquisition systems outside of the vacuum via a lens relay (embedded in a 3D-printed titanium holder) and an in-vacuum image guide. A charge coupled device camera, for high velocity-space resolution, and an 8 × 8 channel avalanche photo diode camera, for high temporal resolution (up to 2 MHz), are used as light acquisition systems. Initial results showing velocity-space of neutral beam injection prompt losses and fast-ion losses induced by a (2, 1) neoclassical tearing mode are presented.
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Affiliation(s)
- J Gonzalez-Martin
- Department of Mechanical and Manufacturing Engineering, University of Seville, C/Camino de los Descubrimientos s/n, Isla de la Cartuja, Seville, Spain
| | - J Ayllon-Guerola
- Department of Mechanical and Manufacturing Engineering, University of Seville, C/Camino de los Descubrimientos s/n, Isla de la Cartuja, Seville, Spain
| | | | - A Herrmann
- Max-Planck-Institut für Plasmaphysik, Garching, Germany
| | - P Leitenstern
- Max-Planck-Institut für Plasmaphysik, Garching, Germany
| | - P De Marne
- Max-Planck-Institut für Plasmaphysik, Garching, Germany
| | | | | | | | - J Rivero-Rodriguez
- Department of Mechanical and Manufacturing Engineering, University of Seville, C/Camino de los Descubrimientos s/n, Isla de la Cartuja, Seville, Spain
| | | | | | - J Dominguez
- Department of Mechanical and Manufacturing Engineering, University of Seville, C/Camino de los Descubrimientos s/n, Isla de la Cartuja, Seville, Spain
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13
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Zoletnik S, Anda G, Aradi M, Asztalos O, Bató S, Bencze A, Berta M, Demeter G, Dunai D, Hacek P, Hegedűs S, Hu GH, Krizsanóczi T, Lampert M, Nagy D, Németh J, Otte M, Petravich G, Pokol GI, Réfy D, Tál B, Vécsei M. Advanced neutral alkali beam diagnostics for applications in fusion research (invited). THE REVIEW OF SCIENTIFIC INSTRUMENTS 2018; 89:10D107. [PMID: 30399868 DOI: 10.1063/1.5039309] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Accepted: 06/15/2018] [Indexed: 06/08/2023]
Abstract
Diagnosing the density profile at the edge of high temperature fusion plasmas by an accelerated lithium beam is a known technique since decades. By knowledge of the relevant atomic physics rate coefficients, the plasma electron density profile can be calculated from the relatively calibrated light profile along the beam. Several additional possibilities have already been demonstrated: Charge Exchange Resonance Spectroscopy (CXRS) for ion temperature/flow and Zeeman polarimetry for edge plasma current; therefore the Li-beam diagnostic offers a wealth of information at the plasma edge. The weaknesses of the method are the relatively faint light signal, background light, and technical difficulties of the beam injector which usually seriously limit the applicability. In this talk, we present systematic developments in alkali-beam diagnostics (Li, Na) for the injector and the observation system and detectors which resulted in strongly increased capabilities. Advanced systems have been built, and microsecond scale density profile, turbulence, and zonal flow measurement have been demonstrated. A novel edge current measurement technique has also been designed, and components have been tested with potential microsecond-scale time resolution. Additional possibilities of these advanced systems for spectral measurements (CXRS and various Zeeman schemes) are also discussed.
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Affiliation(s)
- S Zoletnik
- Wigner Research Centre for Physics, Budapest, Hungary
| | - G Anda
- Wigner Research Centre for Physics, Budapest, Hungary
| | - M Aradi
- Graz University of Technology, Graz, Austria
| | - O Asztalos
- Budapest University of Technology and Economics, Budapest, Hungary
| | - S Bató
- Wigner Research Centre for Physics, Budapest, Hungary
| | - A Bencze
- Wigner Research Centre for Physics, Budapest, Hungary
| | - M Berta
- Széchenyi University, Győr, Hungary
| | - G Demeter
- Wigner Research Centre for Physics, Budapest, Hungary
| | - D Dunai
- Wigner Research Centre for Physics, Budapest, Hungary
| | - P Hacek
- Institute for Plasma Physics, Czech Academy of Sciences, Prague, Czech Republic
| | - S Hegedűs
- Wigner Research Centre for Physics, Budapest, Hungary
| | - G H Hu
- Institute for Plasma Physics, Chinese Academy of Sciences, Hefei, China
| | - T Krizsanóczi
- Wigner Research Centre for Physics, Budapest, Hungary
| | - M Lampert
- Wigner Research Centre for Physics, Budapest, Hungary
| | - D Nagy
- Wigner Research Centre for Physics, Budapest, Hungary
| | - J Németh
- Wigner Research Centre for Physics, Budapest, Hungary
| | - M Otte
- Max Planck Institute for Plasma Physics, Greifswald, Germany
| | - G Petravich
- Wigner Research Centre for Physics, Budapest, Hungary
| | - G I Pokol
- Budapest University of Technology and Economics, Budapest, Hungary
| | - D Réfy
- Wigner Research Centre for Physics, Budapest, Hungary
| | - B Tál
- Wigner Research Centre for Physics, Budapest, Hungary
| | - M Vécsei
- Wigner Research Centre for Physics, Budapest, Hungary
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14
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Réfy DI, Brix M, Gomes R, Tál B, Zoletnik S, Dunai D, Kocsis G, Kálvin S, Szabolics T. Sub-millisecond electron density profile measurement at the JET tokamak with the fast lithium beam emission spectroscopy system. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2018; 89:043509. [PMID: 29716310 DOI: 10.1063/1.4986621] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Diagnostic alkali atom (e.g., lithium) beams are routinely used to diagnose magnetically confined plasmas, namely, to measure the plasma electron density profile in the edge and the scrape off layer region. A light splitting optics system was installed into the observation system of the lithium beam emission spectroscopy diagnostic at the Joint European Torus (JET) tokamak, which allows simultaneous measurement of the beam light emission with a spectrometer and a fast avalanche photodiode (APD) camera. The spectrometer measurement allows density profile reconstruction with ∼10 ms time resolution, absolute position calculation from the Doppler shift, spectral background subtraction as well as relative intensity calibration of the channels for each discharge. The APD system is capable of measuring light intensities on the microsecond time scale. However ∼100 μs integration is needed to have an acceptable signal to noise ratio due to moderate light levels. Fast modulation of the beam up to 30 kHz is implemented which allows background subtraction on the 100 μs time scale. The measurement covers the 0.9 < ρpol < 1.1 range with 6-10 mm optical resolution at the measurement location which translates to 3-5 mm radial resolution at the midplane due to flux expansion. An automated routine has been developed which performs the background subtraction, the relative calibration, and the comprehensive error calculation, runs a Bayesian density reconstruction code, and loads results to the JET database. The paper demonstrates the capability of the APD system by analyzing fast phenomena like pellet injection and edge localized modes.
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Affiliation(s)
- D I Réfy
- Wigner Research Centre for Physics, XII Konkoly Thege Miklós út 29-33, Budapest 1121, Hungary
| | - M Brix
- CCFE, Culham Science Centre, Abingdon, Oxon OX14 3DB, United Kingdom
| | - R Gomes
- Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal
| | - B Tál
- Wigner Research Centre for Physics, XII Konkoly Thege Miklós út 29-33, Budapest 1121, Hungary
| | - S Zoletnik
- Wigner Research Centre for Physics, XII Konkoly Thege Miklós út 29-33, Budapest 1121, Hungary
| | - D Dunai
- Wigner Research Centre for Physics, XII Konkoly Thege Miklós út 29-33, Budapest 1121, Hungary
| | - G Kocsis
- Wigner Research Centre for Physics, XII Konkoly Thege Miklós út 29-33, Budapest 1121, Hungary
| | - S Kálvin
- Wigner Research Centre for Physics, XII Konkoly Thege Miklós út 29-33, Budapest 1121, Hungary
| | - T Szabolics
- Wigner Research Centre for Physics, XII Konkoly Thege Miklós út 29-33, Budapest 1121, Hungary
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15
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Feasibility study on the JT-60SA tokamak beam emission spectroscopy diagnostics. FUSION ENGINEERING AND DESIGN 2017. [DOI: 10.1016/j.fusengdes.2017.03.125] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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16
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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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17
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Anda G, Bencze A, Berta M, Dunai D, Hacek P, Krbec J, Réfy D, Krizsanóczi T, Bató S, Ilkei T, Kiss I, Veres G, Zoletnik S. Lithium beam diagnostic system on the COMPASS tokamak. FUSION ENGINEERING AND DESIGN 2016. [DOI: 10.1016/j.fusengdes.2016.04.022] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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18
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Li-BES detection system for plasma turbulence measurements on the COMPASS tokamak. FUSION ENGINEERING AND DESIGN 2015. [DOI: 10.1016/j.fusengdes.2015.06.030] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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19
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Lampert M, Anda G, Czopf A, Erdei G, Guszejnov D, Kovácsik Á, Pokol GI, Réfy D, Nam YU, Zoletnik S. Combined hydrogen and lithium beam emission spectroscopy observation system for Korea Superconducting Tokamak Advanced Research. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2015; 86:073501. [PMID: 26233377 DOI: 10.1063/1.4923251] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
A novel beam emission spectroscopy observation system was designed, built, and installed onto the Korea Superconducting Tokamak Advanced Research tokamak. The system is designed in a way to be capable of measuring beam emission either from a heating deuterium or from a diagnostic lithium beam. The two beams have somewhat complementary capabilities: edge density profile and turbulence measurement with the lithium beam and two dimensional turbulence measurement with the heating beam. Two detectors can be used in parallel: a CMOS camera provides overview of the scene and lithium beam light intensity distribution at maximum few hundred Hz frame rate, while a 4 × 16 pixel avalanche photo-diode (APD) camera gives 500 kHz bandwidth data from a 4 cm × 16 cm region. The optics use direct imaging through lenses and mirrors from the observation window to the detectors, thus avoid the use of costly and inflexible fiber guides. Remotely controlled mechanisms allow adjustment of the APD camera's measurement location on a shot-to-shot basis, while temperature stabilized filter holders provide selection of either the Doppler shifted deuterium alpha or lithium resonance line. The capabilities of the system are illustrated by measurements of basic plasma turbulence properties.
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Affiliation(s)
- M Lampert
- Wigner RCP, Euratom Association-HAS, Budapest, Hungary
| | - G Anda
- Wigner RCP, Euratom Association-HAS, Budapest, Hungary
| | - A Czopf
- Department of Atomic Physics, BME IOP, Budapest, Hungary
| | - G Erdei
- Department of Atomic Physics, BME IOP, Budapest, Hungary
| | | | | | | | - D Réfy
- Wigner RCP, Euratom Association-HAS, Budapest, Hungary
| | - Y U Nam
- National Fusion Research Institute, Daejeon, Korea
| | - S Zoletnik
- Wigner RCP, Euratom Association-HAS, Budapest, Hungary
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20
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Gregorio E, Rocadenbosch F, Sanz R, Rosell-Polo JR. Eye-safe lidar system for pesticide spray drift measurement. SENSORS 2015; 15:3650-70. [PMID: 25658395 PMCID: PMC4367378 DOI: 10.3390/s150203650] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/29/2014] [Revised: 01/19/2015] [Accepted: 01/28/2015] [Indexed: 11/30/2022]
Abstract
Spray drift is one of the main sources of pesticide contamination. For this reason, an accurate understanding of this phenomenon is necessary in order to limit its effects. Nowadays, spray drift is usually studied by using in situ collectors which only allow time-integrated sampling of specific points of the pesticide clouds. Previous research has demonstrated that the light detection and ranging (lidar) technique can be an alternative for spray drift monitoring. This technique enables remote measurement of pesticide clouds with high temporal and distance resolution. Despite these advantages, the fact that no lidar instrument suitable for such an application is presently available has appreciably limited its practical use. This work presents the first eye-safe lidar system specifically designed for the monitoring of pesticide clouds. Parameter design of this system is carried out via signal-to-noise ratio simulations. The instrument is based on a 3-mJ pulse-energy erbium-doped glass laser, an 80-mm diameter telescope, an APD optoelectronic receiver and optomechanically adjustable components. In first test measurements, the lidar system has been able to measure a topographic target located over 2 km away. The instrument has also been used in spray drift studies, demonstrating its capability to monitor the temporal and distance evolution of several pesticide clouds emitted by air-assisted sprayers at distances between 50 and 100 m.
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Affiliation(s)
- Eduard Gregorio
- Department of Agricultural and Forest Engineering, Research Group on AgroICT & Precision Agriculture, Universitat de Lleida (UdL), Campus Cappont, Bldg CREA, Pere de Cabrera s/n, 25001 Lleida, Spain.
| | - Francesc Rocadenbosch
- Department of Signal Theory and Communications, Remote Sensing Laboratory, Universitat Politècnica de Catalunya (UPC), Campus Nord, Bldg D4, Jordi Girona 1-3, 08034 Barcelona, Spain.
| | - Ricardo Sanz
- Department of Agricultural and Forest Engineering, Research Group on AgroICT & Precision Agriculture, Universitat de Lleida (UdL), Campus ETSEA, Av/ Rovira Roure 191, 25198 Lleida, Spain.
| | - Joan R Rosell-Polo
- Department of Agricultural and Forest Engineering, Research Group on AgroICT & Precision Agriculture, Universitat de Lleida (UdL), Campus ETSEA, Av/ Rovira Roure 191, 25198 Lleida, Spain.
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21
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Hron M, Janky F, Pipek J, Sousa J, Carvalho B, Fernandes H, Vondracek P, Cahyna P, Urban J, Paprok R, Mikulín O, Aftanas M, Panek R, Havlicek J, Fortunato J, Batista A, Santos B, Duarte A, Pereira T, Valcarcel D. Overview of the COMPASS CODAC system. FUSION ENGINEERING AND DESIGN 2014. [DOI: 10.1016/j.fusengdes.2013.09.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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22
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Berta M, Anda G, Aradi M, Bencze A, Buday C, Kiss I, Tulipán S, Veres G, Zoletnik S, Havlícek J, Háček P. Development of atomic beam probe for tokamaks. FUSION ENGINEERING AND DESIGN 2013. [DOI: 10.1016/j.fusengdes.2013.05.064] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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23
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Pokol G, Zoletnik S, Dunai D, Marchuk O, Baross T, Erdei G, Grunda G, Kiss I, Kovacsik A, v.Hellermann M, Lischtschenko O, Biel W, Jaspers R, Durkut M. Fluctuation BES measurements with the ITER core CXRS prototype spectrometer. FUSION ENGINEERING AND DESIGN 2013. [DOI: 10.1016/j.fusengdes.2013.02.171] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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24
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Brix M, Dodt D, Dunai D, Lupelli I, Marsen S, Melson TF, Meszaros B, Morgan P, Petravich G, Refy DI, Silva C, Stamp M, Szabolics T, Zastrow KD, Zoletnik S. Recent improvements of the JET lithium beam diagnostic. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2012; 83:10D533. [PMID: 23130794 DOI: 10.1063/1.4739411] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
A 60 kV neutral lithium diagnostic beam probes the edge plasma of JET for the measurement of electron density profiles. This paper describes recent enhancements of the diagnostic setup, new procedures for calibration and protection measures for the lithium ion gun during massive gas puffs for disruption mitigation. New light splitting optics allow in parallel beam emission measurements with a new double entrance slit CCD spectrometer (spectrally resolved) and a new interference filter avalanche photodiode camera (fast density and fluctuation studies).
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Affiliation(s)
- M Brix
- EURATOM∕CCFE Fusion Association, Culham Science Centre, OX14 3DB Abingdon, United Kingdom.
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25
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Nam YU, Zoletnik S, Lampert M, Kovácsik Á. Analysis of edge density fluctuation measured by trial KSTAR beam emission spectroscopy system. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2012; 83:10D531. [PMID: 23126870 DOI: 10.1063/1.4739078] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
A beam emission spectroscopy (BES) system based on direct imaging avalanche photodiode (APD) camera has been designed for Korea Superconducting Tokamak Advanced Research (KSTAR) and a trial system has been constructed and installed for evaluating feasibility of the design. The system contains two cameras, one is an APD camera for BES measurement and another is a fast visible camera for position calibration. Two pneumatically actuated mirrors were positioned at front and rear of lens optics. The front mirror can switch the measurement between edge and core region of plasma and the rear mirror can switch between the APD and the visible camera. All systems worked properly and the measured photon flux was reasonable as expected from the simulation. While the measurement data from the trial system were limited, it revealed some interesting characteristics of KSTAR plasma suggesting future research works with fully installed BES system. The analysis result and the development plan will be presented in this paper.
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Affiliation(s)
- Y U Nam
- National Fusion Research Institute, Daejeon, South Korea.
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26
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Kruezi U, Stoschus H, Schweer B, Sergienko G, Samm U. Supersonic helium beam diagnostic for fluctuation measurements of electron temperature and density at the Tokamak TEXTOR. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2012; 83:065107. [PMID: 22755662 DOI: 10.1063/1.4707150] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
A supersonic helium beam diagnostic, based on the line-ratio technique for high resolution electron density and temperature measurements in the plasma edge (r/a > 0.9) was designed, built, and optimised at TEXTOR (Torus Experiment for Technology Oriented Research). The supersonic injection system, based on the Campargue skimmer-nozzle concept, was developed and optimised in order to provide both a high neutral helium beam density of n(0) = 1.5 × 10(18) m(-3) and a low beam divergence of ±1° simultaneously, achieving a poloidal resolution of Δ(poloidal) = 9 mm. The setup utilises a newly developed dead volume free piezo valve for operation in a high magnetic field environment of up to 2 T with a maximum repetition rate of 80 Hz. Gas injections are realised for a duration of 120 ms at a repetition rate of 2 Hz (duty cycle 1/3). In combination with a high sensitivity detection system, consisting of three 32 multi-channel photomultipliers (PMTs), measurements of edge electron temperature and density with a radial resolution of Δ(radial) = 2 mm and a maximum temporal resolution of Δt ≃ 2 μs (470 kHz) are possible for the first time. The diagnostic setup at TEXTOR is presented. The newly developed injection system and its theoretical bases are discussed. The applicability of the stationary collisional-radiative model as basis of the line-ratio technique is shown. Finally, an example of a fluctuation analysis demonstrating the unique high temporal and spatial resolution capabilities of this new diagnostic is presented.
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Affiliation(s)
- U Kruezi
- Institute of Energy and Climate Research, Plasma Physics, Forschungszentrum Jülich GmbH, Association EURATOM-FZJ, Partner in the Trilateral Euregio Cluster, Jülich, Germany.
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27
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Willensdorfer M, Wolfrum E, Fischer R, Schweinzer J, Sertoli M, Sieglin B, Veres G, Aumayr F. Improved chopping of a lithium beam for plasma edge diagnostic at ASDEX Upgrade. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2012; 83:023501. [PMID: 22413779 DOI: 10.1063/1.3682003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The lithium beam diagnostic at ASDEX Upgrade routinely delivers electron density profiles in the plasma edge by lithium beam impact excitation spectroscopy. An accurate background subtraction requires a periodically chopped lithium beam. A new, improved chopping system was developed and installed. It involves a voltage modulation for the extractor electrode and the beam deflection plates. The modulation of the extractor electrode reduces the unused portion of lithium ions and improves the stability of the beam with respect to its position. Furthermore, the data indicate an extended emitter lifetime. The extractor chopping was also found to be insensitive to sparks. The deflection chopping experiments demonstrated beam chopping in the kilohertz range. The significantly higher modulation frequency of the deflection chopping improves background subtraction of fast transient events. It allows a more accurate density measurements in the scrape off layer during impurity injections and edge localized modes.
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Affiliation(s)
- M Willensdorfer
- Institute of Applied Physics, Vienna University of Technology, Association EURATOM-ÖAW, A-1040 Vienna, Austria.
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28
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Field AR, Dunai D, Gaffka R, Ghim YC, Kiss I, Mészáros B, Krizsanóczi T, Shibaev S, Zoletnik S. Beam emission spectroscopy turbulence imaging system for the MAST spherical tokamak. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2012; 83:013508. [PMID: 22299952 DOI: 10.1063/1.3669756] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
A new beam emission spectroscopy turbulence imaging system has recently been installed onto the MAST spherical tokamak. The system utilises a high-throughput, direct coupled imaging optics, and a single large interference filter for collection of the Doppler shifted D(α) emission from the ~2 MW heating beam of ~70 keV injection energy. The collected light is imaged onto a 2D array detector with 8 × 4 avalanche photodiode sensors which is incorporated into a custom camera unit to perform simultaneous 14-bit digitization at 2 MHz of all 32 channels. The array is imaged at the beam to achieve a spatial resolution of ~2 cm in the radial (horizontal) and poloidal (vertical) directions, which is sufficient for detection of the ion-scale plasma turbulence. At the typical photon fluxes of ~10(11) s(-1) the achieved signal-to-noise ratio of ~300 at the 0.5 MHz analogue bandwidth is sufficient for detection of relative density fluctuations at the level of a few 0.1%. The system is to be utilised for the study of the characteristics of the broadband, ion-scale turbulence, in particular its interaction with flow shear, as well as coherent fluctuations due to various types of MHD activity.
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Affiliation(s)
- A R Field
- EURATOM/UKAEA Fusion Association, Culham Science Centre, Abingdon, Oxon, United Kingdom
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29
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Kiss IG, Mészáros B, Dunai D, Zoletnik S, Krizsanóczi T, Field AR, Gaffka R. Mechanical design of the two dimensional beam emission spectroscopy diagnostics on mast. FUSION ENGINEERING AND DESIGN 2011. [DOI: 10.1016/j.fusengdes.2010.11.027] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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