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Li B, Levesque JP, Wei Y, Saperstein A, Chandra RN, Navratil GA, Mauel ME, Hansen C. Tangential extreme ultraviolet and soft x-ray diagnostic system for time-resolved temperature measurement on the High Beta Tokamak-Extended Pulse. Rev Sci Instrum 2023; 94:103503. [PMID: 37796093 DOI: 10.1063/5.0153115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Accepted: 09/20/2023] [Indexed: 10/06/2023]
Abstract
The High Beta Tokamak-Extended Pulse has recently incorporated a tangential multi-energy extreme ultraviolet and soft x-ray diagnostic system. This system enables measurements of the electron temperature and the examination of mode dynamics within the tokamak. While other systems have been built for poloidal views over similar temperature ranges, this is the first multi-energy tangential-view system designed to work in a temperature range below 200 eV in a tokamak. To facilitate these measurements, a filter wheel comprising five distinct groups of dual-filters has been developed and implemented. By employing a combination of 0.1 μm aluminum and 0.2 μm titanium filters, the system allows estimation of electron temperature profiles through reconstruction of the emission profile using the standard "double-foil" technique. The influence of impurities and filter oxide layers on measurement outcomes is examined. Results reveal that, while the absolute electron temperature values may exhibit some deviations, key characteristics like the electron temperature profile shape and inversion radius during sawtooth events remain consistent. This consistency confirms the system's suitability for core plasma studies. This system has proven effective in detecting and analyzing internal magnetohydrodynamic phenomena, such as sawteeth.
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Affiliation(s)
- Boting Li
- Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027, USA
| | - J P Levesque
- Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027, USA
| | - Y Wei
- Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027, USA
| | - A Saperstein
- Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027, USA
| | - R N Chandra
- Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027, USA
| | - G A Navratil
- Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027, USA
| | - M E Mauel
- Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027, USA
| | - C Hansen
- Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027, USA
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Brooks JW, Stewart IG, Boyer MD, Levesque JP, Mauel ME, Navratil GA. Mode rotation control in a tokamak with a feedback-driven biased electrode. Rev Sci Instrum 2019; 90:023503. [PMID: 30831681 DOI: 10.1063/1.5062271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Accepted: 02/01/2019] [Indexed: 06/09/2023]
Abstract
Rotation of the plasma and MHD modes in tokamaks has been shown to stabilize resistive wall and tearing modes as well as improve confinement through suppression of edge turbulence. In this work, we control mode rotation with a biased electrode inserted into the plasma of the High Beta Tokamak-Extended Pulse's facility in conjunction with its active GPU (Graphical Processing Unit) feedback system. We first characterize a negative linear relationship between the electrode voltage and mode rotation. Using this relationship, we design, simulate, and implement a proof-of-concept, GPU-based active-control system, which shows consistent success in controlling mode rotation in both feedforward and feedback operation. Controllability is limited by operating conditions, the electrode's voltage range, and by the electrode's proximity to the vessel's walls. The final control system has a 15 μs cycle time, but the addition of various signal filters results in a full cycle latency of 200 μs.
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Affiliation(s)
- J W Brooks
- Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027, USA
| | - I G Stewart
- Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027, USA
| | - M D Boyer
- Princeton Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08543, USA
| | - J P Levesque
- Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027, USA
| | - M E Mauel
- Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027, USA
| | - G A Navratil
- Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027, USA
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3
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Hawryluk RJ, Mueller D, Hosea J, Barnes CW, Beer M, Bell MG, Bell R, Biglari H, Bitter M, Boivin R, Bretz NL, Budny R, Bush CE, Chen L, Cheng CZ, Cowley S, Dairow DS, Efthimion PC, Fonck RJ, Fredrickson E, Furth HP, Greene G, Grek B, Grisham LR, Hammett G, Heidbrink W, Hill KW, Hoffman D, Hulse RA, Hsuan H, Janos A, Jassby DL, Jobes FC, Johnson DW, Johnson LC, Kamperschroer J, Kesner J, Phillips CK, Kilpatrick SJ, Kugel H, LaMarche PH, LeBlanc B, Manos DM, Mansfield DK, Marmar ES, Mazzucato E, McCarthy MP, Machuzak J, Mauel M, McCune D, McGuire KM, Medley SS, Monticello DR, Mikkelsen D, Nagayama Y, Navratil GA, Nazikian R, Owens DK, Park H, Park W, Paul S, Perkins F, Pitcher S, Rasmussen D, Redi MH, Rewoldt G, Roberts D, Roquemore AL, Sabbagh S, Schilling G, Schivell J, Schmidt GL, Scott SD, Snipes J, Stevens J, Stratton BC, Strachan JD, Stodiek W, Synakowski E, Tang W, Taylor G, Terry J, Timberlake JR, Ulrickson HH, Towner M, von Goeler S, Wieland R, Wilson JR, Wong KL, Woskov P, Yamada M, Young KM, Zamstorff MC, Zweben SJ. Status and Plans for TFTR. ACTA ACUST UNITED AC 2017. [DOI: 10.13182/fst92-a29907] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- R. J. Hawryluk
- Plasma Physics Laboratory, Princeton University P.O. Box 451 Princeton, N.J. 08543 USA (609) 243-3306
| | - D. Mueller
- Plasma Physics Laboratory, Princeton University P.O. Box 451 Princeton, N.J. 08543 USA (609) 243-3306
| | - J. Hosea
- Plasma Physics Laboratory, Princeton University P.O. Box 451 Princeton, N.J. 08543 USA (609) 243-3306
| | | | - M. Beer
- Plasma Physics Laboratory, Princeton University P.O. Box 451 Princeton, N.J. 08543 USA (609) 243-3306
| | - M. G. Bell
- Plasma Physics Laboratory, Princeton University P.O. Box 451 Princeton, N.J. 08543 USA (609) 243-3306
| | - R. Bell
- Plasma Physics Laboratory, Princeton University P.O. Box 451 Princeton, N.J. 08543 USA (609) 243-3306
| | - H. Biglari
- Plasma Physics Laboratory, Princeton University P.O. Box 451 Princeton, N.J. 08543 USA (609) 243-3306
| | - M. Bitter
- Plasma Physics Laboratory, Princeton University P.O. Box 451 Princeton, N.J. 08543 USA (609) 243-3306
| | - R. Boivin
- Massachusetts Institute of Technology, Cambridge, MA
| | - N. L. Bretz
- Plasma Physics Laboratory, Princeton University P.O. Box 451 Princeton, N.J. 08543 USA (609) 243-3306
| | - R. Budny
- Plasma Physics Laboratory, Princeton University P.O. Box 451 Princeton, N.J. 08543 USA (609) 243-3306
| | - C. E. Bush
- Oak Ridge National Laboratory, Oak Ridge, TN
| | - L. Chen
- Plasma Physics Laboratory, Princeton University P.O. Box 451 Princeton, N.J. 08543 USA (609) 243-3306
| | - C. Z. Cheng
- Plasma Physics Laboratory, Princeton University P.O. Box 451 Princeton, N.J. 08543 USA (609) 243-3306
| | - S. Cowley
- Plasma Physics Laboratory, Princeton University P.O. Box 451 Princeton, N.J. 08543 USA (609) 243-3306
| | - D. S. Dairow
- Plasma Physics Laboratory, Princeton University P.O. Box 451 Princeton, N.J. 08543 USA (609) 243-3306
| | - P. C. Efthimion
- Plasma Physics Laboratory, Princeton University P.O. Box 451 Princeton, N.J. 08543 USA (609) 243-3306
| | | | - E. Fredrickson
- Plasma Physics Laboratory, Princeton University P.O. Box 451 Princeton, N.J. 08543 USA (609) 243-3306
| | - H. P. Furth
- Plasma Physics Laboratory, Princeton University P.O. Box 451 Princeton, N.J. 08543 USA (609) 243-3306
| | - G. Greene
- Plasma Physics Laboratory, Princeton University P.O. Box 451 Princeton, N.J. 08543 USA (609) 243-3306
| | - B. Grek
- Plasma Physics Laboratory, Princeton University P.O. Box 451 Princeton, N.J. 08543 USA (609) 243-3306
| | - L. R. Grisham
- Plasma Physics Laboratory, Princeton University P.O. Box 451 Princeton, N.J. 08543 USA (609) 243-3306
| | - G. Hammett
- Plasma Physics Laboratory, Princeton University P.O. Box 451 Princeton, N.J. 08543 USA (609) 243-3306
| | | | - K. W. Hill
- Plasma Physics Laboratory, Princeton University P.O. Box 451 Princeton, N.J. 08543 USA (609) 243-3306
| | - D. Hoffman
- Oak Ridge National Laboratory, Oak Ridge, TN
| | - R. A. Hulse
- Plasma Physics Laboratory, Princeton University P.O. Box 451 Princeton, N.J. 08543 USA (609) 243-3306
| | - H. Hsuan
- Plasma Physics Laboratory, Princeton University P.O. Box 451 Princeton, N.J. 08543 USA (609) 243-3306
| | - A. Janos
- Plasma Physics Laboratory, Princeton University P.O. Box 451 Princeton, N.J. 08543 USA (609) 243-3306
| | - D. L. Jassby
- Plasma Physics Laboratory, Princeton University P.O. Box 451 Princeton, N.J. 08543 USA (609) 243-3306
| | - F. C. Jobes
- Plasma Physics Laboratory, Princeton University P.O. Box 451 Princeton, N.J. 08543 USA (609) 243-3306
| | - D. W. Johnson
- Plasma Physics Laboratory, Princeton University P.O. Box 451 Princeton, N.J. 08543 USA (609) 243-3306
| | - L. C. Johnson
- Plasma Physics Laboratory, Princeton University P.O. Box 451 Princeton, N.J. 08543 USA (609) 243-3306
| | - J. Kamperschroer
- Plasma Physics Laboratory, Princeton University P.O. Box 451 Princeton, N.J. 08543 USA (609) 243-3306
| | - J. Kesner
- Massachusetts Institute of Technology, Cambridge, MA
| | - C. K. Phillips
- Plasma Physics Laboratory, Princeton University P.O. Box 451 Princeton, N.J. 08543 USA (609) 243-3306
| | - S. J. Kilpatrick
- Plasma Physics Laboratory, Princeton University P.O. Box 451 Princeton, N.J. 08543 USA (609) 243-3306
| | - H. Kugel
- Plasma Physics Laboratory, Princeton University P.O. Box 451 Princeton, N.J. 08543 USA (609) 243-3306
| | - P. H. LaMarche
- Plasma Physics Laboratory, Princeton University P.O. Box 451 Princeton, N.J. 08543 USA (609) 243-3306
| | - B. LeBlanc
- Plasma Physics Laboratory, Princeton University P.O. Box 451 Princeton, N.J. 08543 USA (609) 243-3306
| | - D. M. Manos
- Plasma Physics Laboratory, Princeton University P.O. Box 451 Princeton, N.J. 08543 USA (609) 243-3306
| | - D. K. Mansfield
- Plasma Physics Laboratory, Princeton University P.O. Box 451 Princeton, N.J. 08543 USA (609) 243-3306
| | - E. S. Marmar
- Massachusetts Institute of Technology, Cambridge, MA
| | - E. Mazzucato
- Plasma Physics Laboratory, Princeton University P.O. Box 451 Princeton, N.J. 08543 USA (609) 243-3306
| | - M. P. McCarthy
- Plasma Physics Laboratory, Princeton University P.O. Box 451 Princeton, N.J. 08543 USA (609) 243-3306
| | - J. Machuzak
- Massachusetts Institute of Technology, Cambridge, MA
| | - M. Mauel
- Columbia University, New York, NY
| | - D.C. McCune
- Plasma Physics Laboratory, Princeton University P.O. Box 451 Princeton, N.J. 08543 USA (609) 243-3306
| | - K. M. McGuire
- Plasma Physics Laboratory, Princeton University P.O. Box 451 Princeton, N.J. 08543 USA (609) 243-3306
| | - S. S. Medley
- Plasma Physics Laboratory, Princeton University P.O. Box 451 Princeton, N.J. 08543 USA (609) 243-3306
| | - D. R. Monticello
- Plasma Physics Laboratory, Princeton University P.O. Box 451 Princeton, N.J. 08543 USA (609) 243-3306
| | - D. Mikkelsen
- Plasma Physics Laboratory, Princeton University P.O. Box 451 Princeton, N.J. 08543 USA (609) 243-3306
| | | | | | - R. Nazikian
- Plasma Physics Laboratory, Princeton University P.O. Box 451 Princeton, N.J. 08543 USA (609) 243-3306
| | - D. K. Owens
- Plasma Physics Laboratory, Princeton University P.O. Box 451 Princeton, N.J. 08543 USA (609) 243-3306
| | - H. Park
- Plasma Physics Laboratory, Princeton University P.O. Box 451 Princeton, N.J. 08543 USA (609) 243-3306
| | - W. Park
- Plasma Physics Laboratory, Princeton University P.O. Box 451 Princeton, N.J. 08543 USA (609) 243-3306
| | - S. Paul
- Plasma Physics Laboratory, Princeton University P.O. Box 451 Princeton, N.J. 08543 USA (609) 243-3306
| | - F. Perkins
- Plasma Physics Laboratory, Princeton University P.O. Box 451 Princeton, N.J. 08543 USA (609) 243-3306
| | - S. Pitcher
- Canadian Fusion Fuels Technology Project, Toronto, Canada
| | | | - M. H. Redi
- Plasma Physics Laboratory, Princeton University P.O. Box 451 Princeton, N.J. 08543 USA (609) 243-3306
| | - G. Rewoldt
- Plasma Physics Laboratory, Princeton University P.O. Box 451 Princeton, N.J. 08543 USA (609) 243-3306
| | | | - A. L. Roquemore
- Plasma Physics Laboratory, Princeton University P.O. Box 451 Princeton, N.J. 08543 USA (609) 243-3306
| | | | - G. Schilling
- Plasma Physics Laboratory, Princeton University P.O. Box 451 Princeton, N.J. 08543 USA (609) 243-3306
| | - J. Schivell
- Plasma Physics Laboratory, Princeton University P.O. Box 451 Princeton, N.J. 08543 USA (609) 243-3306
| | - G. L. Schmidt
- Plasma Physics Laboratory, Princeton University P.O. Box 451 Princeton, N.J. 08543 USA (609) 243-3306
| | - S. D. Scott
- Plasma Physics Laboratory, Princeton University P.O. Box 451 Princeton, N.J. 08543 USA (609) 243-3306
| | - J. Snipes
- Massachusetts Institute of Technology, Cambridge, MA
| | - J. Stevens
- Plasma Physics Laboratory, Princeton University P.O. Box 451 Princeton, N.J. 08543 USA (609) 243-3306
| | - B. C. Stratton
- Plasma Physics Laboratory, Princeton University P.O. Box 451 Princeton, N.J. 08543 USA (609) 243-3306
| | - J. D. Strachan
- Plasma Physics Laboratory, Princeton University P.O. Box 451 Princeton, N.J. 08543 USA (609) 243-3306
| | - W. Stodiek
- Plasma Physics Laboratory, Princeton University P.O. Box 451 Princeton, N.J. 08543 USA (609) 243-3306
| | - E. Synakowski
- Plasma Physics Laboratory, Princeton University P.O. Box 451 Princeton, N.J. 08543 USA (609) 243-3306
| | - W. Tang
- Plasma Physics Laboratory, Princeton University P.O. Box 451 Princeton, N.J. 08543 USA (609) 243-3306
| | - G. Taylor
- Plasma Physics Laboratory, Princeton University P.O. Box 451 Princeton, N.J. 08543 USA (609) 243-3306
| | - J. Terry
- Massachusetts Institute of Technology, Cambridge, MA
| | - J. R. Timberlake
- Plasma Physics Laboratory, Princeton University P.O. Box 451 Princeton, N.J. 08543 USA (609) 243-3306
| | - H. H. Ulrickson
- Plasma Physics Laboratory, Princeton University P.O. Box 451 Princeton, N.J. 08543 USA (609) 243-3306
| | - M. Towner
- Plasma Physics Laboratory, Princeton University P.O. Box 451 Princeton, N.J. 08543 USA (609) 243-3306
| | - S. von Goeler
- Plasma Physics Laboratory, Princeton University P.O. Box 451 Princeton, N.J. 08543 USA (609) 243-3306
| | - R. Wieland
- Plasma Physics Laboratory, Princeton University P.O. Box 451 Princeton, N.J. 08543 USA (609) 243-3306
| | - J. R. Wilson
- Plasma Physics Laboratory, Princeton University P.O. Box 451 Princeton, N.J. 08543 USA (609) 243-3306
| | - K. L. Wong
- Plasma Physics Laboratory, Princeton University P.O. Box 451 Princeton, N.J. 08543 USA (609) 243-3306
| | - P. Woskov
- Massachusetts Institute of Technology, Cambridge, MA
| | - M. Yamada
- Plasma Physics Laboratory, Princeton University P.O. Box 451 Princeton, N.J. 08543 USA (609) 243-3306
| | - K. M. Young
- Plasma Physics Laboratory, Princeton University P.O. Box 451 Princeton, N.J. 08543 USA (609) 243-3306
| | - M. C. Zamstorff
- Plasma Physics Laboratory, Princeton University P.O. Box 451 Princeton, N.J. 08543 USA (609) 243-3306
| | - S. J. Zweben
- Plasma Physics Laboratory, Princeton University P.O. Box 451 Princeton, N.J. 08543 USA (609) 243-3306
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Hughes PE, Levesque JP, Rivera N, Mauel ME, Navratil GA. Design and installation of a ferromagnetic wall in tokamak geometry. Rev Sci Instrum 2015; 86:103504. [PMID: 26520952 DOI: 10.1063/1.4932312] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Accepted: 09/22/2015] [Indexed: 06/05/2023]
Abstract
Low-activation ferritic steels are leading material candidates for use in next-generation fusion development experiments such as a prospective component test facility and DEMO power reactor. Understanding the interaction of plasmas with a ferromagnetic wall will provide crucial physics for these facilities. In order to study ferromagnetic effects in toroidal geometry, a ferritic wall upgrade was designed and installed in the High Beta Tokamak-Extended Pulse (HBT-EP). Several material options were investigated based on conductivity, magnetic permeability, vacuum compatibility, and other criteria, and the material of choice (high-cobalt steel) is characterized. Installation was accomplished quickly, with minimal impact on existing diagnostics and overall machine performance, and initial results demonstrate the effects of the ferritic wall on plasma stability.
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Affiliation(s)
- P E Hughes
- Columbia University Plasma Physics Laboratory, Columbia University, 102 S.W. Mudd, 500 W. 120th St., New York, New York 10027, USA
| | - J P Levesque
- Columbia University Plasma Physics Laboratory, Columbia University, 102 S.W. Mudd, 500 W. 120th St., New York, New York 10027, USA
| | - N Rivera
- Columbia University Plasma Physics Laboratory, Columbia University, 102 S.W. Mudd, 500 W. 120th St., New York, New York 10027, USA
| | - M E Mauel
- Columbia University Plasma Physics Laboratory, Columbia University, 102 S.W. Mudd, 500 W. 120th St., New York, New York 10027, USA
| | - G A Navratil
- Columbia University Plasma Physics Laboratory, Columbia University, 102 S.W. Mudd, 500 W. 120th St., New York, New York 10027, USA
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Piovesan P, Hanson JM, Martin P, Navratil GA, Turco F, Bialek J, Ferraro NM, La Haye RJ, Lanctot MJ, Okabayashi M, Paz-Soldan C, Strait EJ, Turnbull AD, Zanca P, Baruzzo M, Bolzonella T, Hyatt AW, Jackson GL, Marrelli L, Piron L, Shiraki D. Tokamak operation with safety factor q95 < 2 via control of MHD stability. Phys Rev Lett 2014; 113:045003. [PMID: 25105626 DOI: 10.1103/physrevlett.113.045003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2013] [Indexed: 06/03/2023]
Abstract
Magnetic feedback control of the resistive-wall mode has enabled the DIII-D tokamak to access stable operation at safety factor q(95) = 1.9 in divertor plasmas for 150 instability growth times. Magnetohydrodynamic stability sets a hard, disruptive limit on the minimum edge safety factor achievable in a tokamak, or on the maximum plasma current at a given toroidal magnetic field. In tokamaks with a divertor, the limit occurs at q(95) = 2, as confirmed in DIII-D. Since the energy confinement time scales linearly with current, this also bounds the performance of a fusion reactor. DIII-D has overcome this limit, opening a whole new high-current regime not accessible before. This result brings significant possible benefits in terms of fusion performance, but it also extends resistive-wall mode physics and its control to conditions never explored before. In present experiments, the q(95) < 2 operation is eventually halted by voltage limits reached in the feedback power supplies, not by intrinsic physics issues. Improvements to power supplies and to control algorithms have the potential to further extend this regime.
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Affiliation(s)
- P Piovesan
- Consorzio RFX, Corso Stati Uniti 4, 35127 Padova, Italy
| | - J M Hanson
- Columbia University, New York, New York 10027, USA
| | - P Martin
- Consorzio RFX, Corso Stati Uniti 4, 35127 Padova, Italy
| | - G A Navratil
- Columbia University, New York, New York 10027, USA
| | - F Turco
- Columbia University, New York, New York 10027, USA
| | - J Bialek
- Columbia University, New York, New York 10027, USA
| | - N M Ferraro
- General Atomics, P.O. Box 85608, San Diego, California 92186-5608, USA
| | - R J La Haye
- General Atomics, P.O. Box 85608, San Diego, California 92186-5608, USA
| | - M J Lanctot
- General Atomics, P.O. Box 85608, San Diego, California 92186-5608, USA
| | - M Okabayashi
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543-0451, USA
| | - C Paz-Soldan
- Oak Ridge Institute for Science and Education, Oak Ridge, Tennessee 37831, USA
| | - E J Strait
- General Atomics, P.O. Box 85608, San Diego, California 92186-5608, USA
| | - A D Turnbull
- General Atomics, P.O. Box 85608, San Diego, California 92186-5608, USA
| | - P Zanca
- Consorzio RFX, Corso Stati Uniti 4, 35127 Padova, Italy
| | - M Baruzzo
- Consorzio RFX, Corso Stati Uniti 4, 35127 Padova, Italy
| | - T Bolzonella
- Consorzio RFX, Corso Stati Uniti 4, 35127 Padova, Italy
| | - A W Hyatt
- General Atomics, P.O. Box 85608, San Diego, California 92186-5608, USA
| | - G L Jackson
- General Atomics, P.O. Box 85608, San Diego, California 92186-5608, USA
| | - L Marrelli
- Consorzio RFX, Corso Stati Uniti 4, 35127 Padova, Italy
| | - L Piron
- Consorzio RFX, Corso Stati Uniti 4, 35127 Padova, Italy
| | - D Shiraki
- Columbia University, New York, New York 10027, USA
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Rath N, Kato S, Levesque JP, Mauel ME, Navratil GA, Peng Q. Fast, multi-channel real-time processing of signals with microsecond latency using graphics processing units. Rev Sci Instrum 2014; 85:045114. [PMID: 24784666 DOI: 10.1063/1.4870901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Fast, digital signal processing (DSP) has many applications. Typical hardware options for performing DSP are field-programmable gate arrays (FPGAs), application-specific integrated DSP chips, or general purpose personal computer systems. This paper presents a novel DSP platform that has been developed for feedback control on the HBT-EP tokamak device. The system runs all signal processing exclusively on a Graphics Processing Unit (GPU) to achieve real-time performance with latencies below 8 μs. Signals are transferred into and out of the GPU using PCI Express peer-to-peer direct-memory-access transfers without involvement of the central processing unit or host memory. Tests were performed on the feedback control system of the HBT-EP tokamak using forty 16-bit floating point inputs and outputs each and a sampling rate of up to 250 kHz. Signals were digitized by a D-TACQ ACQ196 module, processing done on an NVIDIA GTX 580 GPU programmed in CUDA, and analog output was generated by D-TACQ AO32CPCI modules.
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Affiliation(s)
- N Rath
- Department of Applied Physics and Applied Mathematics, Columbia University, 500 W 120th St, New York, New York 10027, USA
| | - S Kato
- Department of Information Engineering, Nagoya University, Nagoya, Japan
| | - J P Levesque
- Department of Applied Physics and Applied Mathematics, Columbia University, 500 W 120th St, New York, New York 10027, USA
| | - M E Mauel
- Department of Applied Physics and Applied Mathematics, Columbia University, 500 W 120th St, New York, New York 10027, USA
| | - G A Navratil
- Department of Applied Physics and Applied Mathematics, Columbia University, 500 W 120th St, New York, New York 10027, USA
| | - Q Peng
- Department of Applied Physics and Applied Mathematics, Columbia University, 500 W 120th St, New York, New York 10027, USA
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Shiraki D, Levesque JP, Bialek J, Byrne PJ, DeBono BA, Mauel ME, Maurer DA, Navratil GA, Pedersen TS, Rath N. In situ "artificial plasma" calibration of tokamak magnetic sensors. Rev Sci Instrum 2013; 84:063502. [PMID: 23822340 DOI: 10.1063/1.4808366] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
A unique in situ calibration technique has been used to spatially calibrate and characterize the extensive new magnetic diagnostic set and close-fitting conducting wall of the High Beta Tokamak-Extended Pulse (HBT-EP) experiment. A new set of 216 Mirnov coils has recently been installed inside the vacuum chamber of the device for high-resolution measurements of magnetohydrodynamic phenomena including the effects of eddy currents in the nearby conducting wall. The spatial positions of these sensors are calibrated by energizing several large in situ calibration coils in turn, and using measurements of the magnetic fields produced by the various coils to solve for each sensor's position. Since the calibration coils are built near the nominal location of the plasma current centroid, the technique is referred to as an "artificial plasma" calibration. The fitting procedure for the sensor positions is described, and results of the spatial calibration are compared with those based on metrology. The time response of the sensors is compared with the evolution of the artificial plasma current to deduce the eddy current contribution to each signal. This is compared with simulations using the VALEN electromagnetic code, and the modeled copper thickness profiles of the HBT-EP conducting wall are adjusted to better match experimental measurements of the eddy current decay. Finally, the multiple coils of the artificial plasma system are also used to directly calibrate a non-uniformly wound Fourier Rogowski coil on HBT-EP.
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Affiliation(s)
- D Shiraki
- Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027, USA
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Levesque JP, Litzner KD, Mauel ME, Maurer DA, Navratil GA, Pedersen TS. A high-power spatial filter for Thomson scattering stray light reduction. Rev Sci Instrum 2011; 82:033501. [PMID: 21456731 DOI: 10.1063/1.3549142] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The Thomson scattering diagnostic on the High Beta Tokamak-Extended Pulse (HBT-EP) is routinely used to measure electron temperature and density during plasma discharges. Avalanche photodiodes in a five-channel interference filter polychromator measure scattered light from a 6 ns, 800 mJ, 1064 nm Nd:YAG laser pulse. A low cost, high-power spatial filter was designed, tested, and added to the laser beamline in order to reduce stray laser light to levels which are acceptable for accurate Rayleigh calibration. A detailed analysis of the spatial filter design and performance is given. The spatial filter can be easily implemented in an existing Thomson scattering system without the need to disturb the vacuum chamber or significantly change the beamline. Although apertures in the spatial filter suffer substantial damage from the focused beam, with proper design they can last long enough to permit absolute calibration.
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Affiliation(s)
- J P Levesque
- Department of Applied Physics and Applied Mathematics, Columbia University, 500 W. 120th Street, New York, New York 10027, USA
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Hanson JM, Klein AJ, Mauel ME, Maurer DA, Navratil GA, Pedersen TS. A digital control system for external magnetohydrodynamic modes in tokamak plasmas. Rev Sci Instrum 2009; 80:043503. [PMID: 19405656 DOI: 10.1063/1.3112607] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
A feedback system for controlling external, long-wavelength magnetohydrodynamic activity is described. The system is comprised of a network of localized magnetic pickup and control coils driven by four independent, low-latency field-programable gate array controllers. The control algorithm incorporates digital spatial filtering to resolve low mode number activity, temporal filtering to correct for frequency-dependent amplitude and phase transfer effects in the control hardware, and a Kalman filter to distinguish the unstable plasma mode from noise.
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Affiliation(s)
- J M Hanson
- Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027, USA.
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10
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Reimerdes H, Garofalo AM, Jackson GL, Okabayashi M, Strait EJ, Chu MS, In Y, La Haye RJ, Lanctot MJ, Liu YQ, Navratil GA, Solomon WM, Takahashi H, Groebner RJ. Reduced critical rotation for resistive-wall mode stabilization in a near-axisymmetric configuration. Phys Rev Lett 2007; 98:055001. [PMID: 17358868 DOI: 10.1103/physrevlett.98.055001] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2006] [Indexed: 05/14/2023]
Abstract
Recent DIII-D experiments with reduced neutral beam torque and minimum nonaxisymmetric perturbations of the magnetic field show a significant reduction of the toroidal plasma rotation required for the stabilization of the resistive-wall mode (RWM) below the threshold values observed in experiments that apply nonaxisymmetric magnetic fields to slow the plasma rotation. A toroidal rotation frequency of less than 10 krad/s at the q=2 surface (measured with charge exchange recombination spectroscopy using C VI) corresponding to 0.3% of the inverse of the toroidal Alfvén time is sufficient to sustain the plasma pressure above the ideal MHD no-wall stability limit. The low-rotation threshold is found to be consistent with predictions by a kinetic model of RWM damping.
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Affiliation(s)
- H Reimerdes
- Columbia University, New York, New York 10027, USA
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Reimerdes H, Chu MS, Garofalo AM, Jackson GL, La Haye RJ, Navratil GA, Okabayashi M, Scoville JT, Strait EJ. Measurement of the resistive-wall-mode stability in a rotating plasma using active MHD spectroscopy. Phys Rev Lett 2004; 93:135002. [PMID: 15524728 DOI: 10.1103/physrevlett.93.135002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2004] [Indexed: 05/24/2023]
Abstract
The stability of the resistive-wall mode (RWM) in DIII-D plasmas above the conventional pressure limit, where toroidal plasma rotation in the order of a few percent of the Alfve n velocity is sufficient to stabilize the n=1 RWM, has been probed using the technique of active MHD spectroscopy at frequencies of a few Hertz. The measured frequency spectrum of the plasma response to externally applied rotating resonant magnetic fields is well described by a single-mode approach and provides an absolute measurement of the damping rate and the natural mode rotation frequency of the stable RWM.
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Affiliation(s)
- H Reimerdes
- Columbia University, New York, New York, USA
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12
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Garofalo AM, Strait EJ, Johnson LC, La Haye RJ, Lazarus EA, Navratil GA, Okabayashi M, Scoville JT, Taylor TS, Turnbull AD. Sustained stabilization of the resistive-wall mode by plasma rotation in the DIII-D tokamak. Phys Rev Lett 2002; 89:235001. [PMID: 12485014 DOI: 10.1103/physrevlett.89.235001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2001] [Indexed: 05/24/2023]
Abstract
Values of the normalized plasma pressure up to twice the free-boundary stability limit predicted by ideal magnetohydrodynamic (MHD) theory have been sustained in the DIII-D tokamak. Long-wavelength modes are stabilized by the resistive wall and rapid plasma toroidal rotation. High rotation speed is maintained by minimization of nonaxisymmetric magnetic fields, overcoming a long-standing impediment [E. J. Strait, Phys. Rev. Lett. 74, 2483 (1995)]]. The ideal-MHD pressure limit calculated with an ideal wall is observed as the operational limit to the normalized plasma pressure.
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Affiliation(s)
- A M Garofalo
- General Atomics, P.O. Box 85608, San Diego, California 92186-5608, USA.
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13
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Lazarus EA, Navratil GA, Greenfield CM, Strait EJ, Austin ME, Burrell KH, Casper TA, Baker DR, DeBoo JC, Doyle EJ, Durst R, Ferron JR, Forest CB, Gohil P, Groebner RJ, Heidbrink WW, Hong R, Houlberg WA, Howald AW, Hsieh C, Hyatt AW, Jackson GL, Kim J, Lao LL, Lasnier CJ, Leonard AW, Lohr J, Maingi R, Miller RL, Murakami M, Osborne TH, Perkins LJ, Petty CC, Rettig CL, Rhodes TL, Rice BW, Sabbagh SA, Schissel DP, Scoville JT, Snider RT, Staebler GM, Stallard BW, Stambaugh RD, Stockdale RE, Taylor PL, Thomas DM, Turnbull AD, Wade MR, Wood R, Whyte D. Higher Fusion Power Gain with Current and Pressure Profile Control in Strongly Shaped DIII-D Tokamak Plasmas. Phys Rev Lett 1996; 77:2714-2717. [PMID: 10062027 DOI: 10.1103/physrevlett.77.2714] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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14
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Sankar MKV, Eisner E, Garofalo A, Gates D, Ivers TH, Kombargi R, Mauel ME, Maurer D, Nadle D, Navratil GA, Xiao Q. Initial high beta operation of the HBT-EP Tokamak. J Fusion Energ 1993. [DOI: 10.1007/bf01079674] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Nagayama Y, Yamada M, Sabbagh SA, Fredrickson ED, Manickam J, Bell M, Budny RV, Cavallo A, Janos AC, Mauel ME, McGuire KM, Navratil GA, Taylor G. Investigation of ballooning modes in high poloidal beta plasmas in the Tokamak Fusion Test Reactor*. ACTA ACUST UNITED AC 1993. [DOI: 10.1063/1.860692] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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16
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Nagayama Y, Sabbagh SA, Manickam J, Fredrickson ED, Bell M, Budny RV, Cavallo A, Janos AC, Mauel ME, McGuire KM, Navratil GA, Taylor G, Yamada M. Observation of ballooning modes in high-temperature tokamak plasmas. Phys Rev Lett 1992; 69:2376-2379. [PMID: 10046469 DOI: 10.1103/physrevlett.69.2376] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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17
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Tham P, Sen AK, Sekiguchi A, Greaves RG, Navratil GA. Feedback-modulated ion beam stabilization of a plasma instability. Phys Rev Lett 1991; 67:204-207. [PMID: 10044521 DOI: 10.1103/physrevlett.67.204] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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Scarmozzino R, Sen AK, Navratil GA. Production and identification of a collisionless, curvature-driven, trapped-particle instability. Phys Rev Lett 1986; 57:1729-1732. [PMID: 10033530 DOI: 10.1103/physrevlett.57.1729] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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