1
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Offeddu N, Wüthrich C, Han W, Theiler C, Golfinopoulos T, Terry JL, Marmar E, Ravetta A, Van Parys G. Analysis techniques for blob properties from gas puff imaging data. Rev Sci Instrum 2023; 94:033512. [PMID: 37012776 DOI: 10.1063/5.0133506] [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: 11/03/2022] [Accepted: 02/25/2023] [Indexed: 06/19/2023]
Abstract
Filamentary structures, also known as blobs, are a prominent feature of turbulence and transport at the edge of magnetically confined plasmas. They cause cross-field particle and energy transport and are, therefore, of interest in tokamak physics and, more generally, nuclear fusion research. Several experimental techniques have been developed to study their properties. Among these, measurements are routinely performed with stationary probes, passive imaging, and, in more recent years, Gas Puff Imaging (GPI). In this work, we present different analysis techniques developed and used on 2D data from the suite of GPI diagnostics in the Tokamak à Configuration Variable, featuring different temporal and spatial resolutions. Although specifically developed to be used on GPI data, these techniques can be employed to analyze 2D turbulence data presenting intermittent, coherent structures. We focus on size, velocity, and appearance frequency evaluation with, among other methods, conditional averaging sampling, individual structure tracking, and a recently developed machine learning algorithm. We describe in detail the implementation of these techniques, compare them against each other, and comment on the scenarios to which these techniques are best applied and on the requirements that the data must fulfill in order to yield meaningful results.
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Affiliation(s)
- N Offeddu
- EPFL, Swiss Plasma Center (SPC), CH-1015 Lausanne, Switzerland
| | - C Wüthrich
- EPFL, Swiss Plasma Center (SPC), CH-1015 Lausanne, Switzerland
| | - W Han
- MIT, Plasma Science and Fusion Center (PSFC), Cambridge, Massachusetts 02139, USA
| | - C Theiler
- EPFL, Swiss Plasma Center (SPC), CH-1015 Lausanne, Switzerland
| | - T Golfinopoulos
- MIT, Plasma Science and Fusion Center (PSFC), Cambridge, Massachusetts 02139, USA
| | - J L Terry
- MIT, Plasma Science and Fusion Center (PSFC), Cambridge, Massachusetts 02139, USA
| | - E Marmar
- MIT, Plasma Science and Fusion Center (PSFC), Cambridge, Massachusetts 02139, USA
| | - A Ravetta
- EPFL, Swiss Plasma Center (SPC), CH-1015 Lausanne, Switzerland
| | - G Van Parys
- EPFL, Swiss Plasma Center (SPC), CH-1015 Lausanne, Switzerland
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2
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Mathews A, Hughes JW, Terry JL, Baek SG. Deep Electric Field Predictions by Drift-Reduced Braginskii Theory with Plasma-Neutral Interactions Based on Experimental Images of Boundary Turbulence. Phys Rev Lett 2022; 129:235002. [PMID: 36563220 DOI: 10.1103/physrevlett.129.235002] [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: 04/26/2022] [Accepted: 11/08/2022] [Indexed: 06/17/2023]
Abstract
We present two-dimensional turbulent electric field calculations via physics-informed deep learning consistent with (i) drift-reduced Braginskii theory under the framework of an axisymmetric fusion plasma with purely toroidal field and (ii) experimental estimates of the fluctuating electron density and temperature on open field lines obtained from analysis of gas puff imaging of a discharge on the Alcator C-Mod tokamak. The inclusion of effects from the locally puffed atomic helium on particle and energy sources within the reduced plasma turbulence model is found to strengthen correlations between the electric field and electron pressure. The neutrals are also directly associated with broadening the distribution of turbulent field amplitudes and increasing E×B shearing rates. This demonstrates a novel approach in plasma experiments by solving for nonlinear dynamics consistent with partial differential equations and data without encoding explicit boundary nor initial conditions.
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Affiliation(s)
- A Mathews
- Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - J W Hughes
- Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - J L Terry
- Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - S G Baek
- Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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3
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Offeddu N, Wüthrich C, Han W, Theiler C, Golfinopoulos T, Terry JL, Marmar E, Galperti C, Andrebe Y, Duval BP, Bertizzolo R, Clement A, Février O, Elaian H, Gönczy D, Landis JD. Gas puff imaging on the TCV tokamak. Rev Sci Instrum 2022; 93:123504. [PMID: 36586925 DOI: 10.1063/5.0126398] [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: 09/15/2022] [Accepted: 11/04/2022] [Indexed: 06/17/2023]
Abstract
We present the design and operation of a suite of Gas Puff Imaging (GPI) diagnostic systems installed on the Tokamak à Configuration Variable (TCV) for the study of turbulence in the plasma edge and Scrape-Off-Layer (SOL). These systems provide the unique ability to simultaneously collect poloidal 2D images of plasma dynamics at the outboard midplane, around the X-point, in both the High-Field Side (HFS) and Low-Field Side (LFS) SOL, and in the divertor region. We describe and characterize an innovative control system for deuterium and helium gas injection, which is becoming the default standard for the other gas injections at TCV. Extensive pre-design studies and the different detection systems are presented, including an array of avalanche photodiodes and a high-speed CMOS camera. First results with spatial and time resolutions of up to ≈2 mm and 0.5 µs, respectively, are described, and future upgrades of the GPI diagnostics for TCV are discussed.
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Affiliation(s)
- N Offeddu
- EPFL, Swiss Plasma Center (SPC), CH-1015 Lausanne, Switzerland
| | - C Wüthrich
- EPFL, Swiss Plasma Center (SPC), CH-1015 Lausanne, Switzerland
| | - W Han
- MIT, Plasma Science and Fusion Center (PSFC), Cambridge, Massachusetts 02139, USA
| | - C Theiler
- EPFL, Swiss Plasma Center (SPC), CH-1015 Lausanne, Switzerland
| | - T Golfinopoulos
- MIT, Plasma Science and Fusion Center (PSFC), Cambridge, Massachusetts 02139, USA
| | - J L Terry
- MIT, Plasma Science and Fusion Center (PSFC), Cambridge, Massachusetts 02139, USA
| | - E Marmar
- MIT, Plasma Science and Fusion Center (PSFC), Cambridge, Massachusetts 02139, USA
| | - C Galperti
- EPFL, Swiss Plasma Center (SPC), CH-1015 Lausanne, Switzerland
| | - Y Andrebe
- EPFL, Swiss Plasma Center (SPC), CH-1015 Lausanne, Switzerland
| | - B P Duval
- EPFL, Swiss Plasma Center (SPC), CH-1015 Lausanne, Switzerland
| | - R Bertizzolo
- EPFL, Swiss Plasma Center (SPC), CH-1015 Lausanne, Switzerland
| | - A Clement
- EPFL, Swiss Plasma Center (SPC), CH-1015 Lausanne, Switzerland
| | - O Février
- EPFL, Swiss Plasma Center (SPC), CH-1015 Lausanne, Switzerland
| | - H Elaian
- EPFL, Swiss Plasma Center (SPC), CH-1015 Lausanne, Switzerland
| | - D Gönczy
- EPFL, Swiss Plasma Center (SPC), CH-1015 Lausanne, Switzerland
| | - J D Landis
- EPFL, Swiss Plasma Center (SPC), CH-1015 Lausanne, Switzerland
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4
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Mathews A, Terry JL, Baek SG, Hughes JW, Kuang AQ, LaBombard B, Miller MA, Stotler D, Reiter D, Zholobenko W, Goto M. Deep modeling of plasma and neutral fluctuations from gas puff turbulence imaging. Rev Sci Instrum 2022; 93:063504. [PMID: 35778003 DOI: 10.1063/5.0088216] [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: 02/14/2022] [Accepted: 05/17/2022] [Indexed: 06/15/2023]
Abstract
The role of turbulence in setting boundary plasma conditions is presently a key uncertainty in projecting to fusion energy reactors. To robustly diagnose edge turbulence, we develop and demonstrate a technique to translate brightness measurements of HeI line radiation into local plasma fluctuations via a novel integrated deep learning framework that combines neutral transport physics and collisional radiative theory for the 33D - 23P transition in atomic helium with unbounded correlation constraints between the electron density and temperature. The tenets for experimental validity are reviewed, illustrating that this turbulence analysis for ionized gases is transferable to both magnetized and unmagnetized environments with arbitrary geometries. Based on fast camera data on the Alcator C-Mod tokamak, we present the first two-dimensional time-dependent experimental measurements of the turbulent electron density, electron temperature, and neutral density, revealing shadowing effects in a fusion plasma using a single spectral line.
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Affiliation(s)
- A Mathews
- MIT Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA
| | - J L Terry
- MIT Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA
| | - S G Baek
- MIT Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA
| | - J W Hughes
- MIT Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA
| | - A Q Kuang
- MIT Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA
| | - B LaBombard
- MIT Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA
| | - M A Miller
- MIT Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA
| | - D Stotler
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08540, USA
| | - D Reiter
- Institut für Laser- und Plasmaphysik, Heinrich-Heine-Universität, Düsseldorf, Nordrhein-Westfalen 40225, Germany
| | - W Zholobenko
- Max-Planck-Institut für Plasmaphysik, Garching, Bayern 85748, Germany
| | - M Goto
- National Institute for Fusion Science, Toki-shi, Gifu-ken 509-5292, Japan
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5
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Reinke ML, Terry JL, van Eden GG, Peterson BJ, Mukai K, Gray TK, Stratton BC. Experimental tests of an infrared video bolometer on Alcator C-Mod. Rev Sci Instrum 2018; 89:103507. [PMID: 30399930 DOI: 10.1063/1.5047050] [Citation(s) in RCA: 2] [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: 07/04/2018] [Accepted: 09/24/2018] [Indexed: 06/08/2023]
Abstract
A prototype of an infrared imaging bolometer (IRVB) was successfully tested on the Alcator C-Mod tokamak at the end of its 2016 campaign. The IRVB method interprets the power radiated from the plasma by measuring the temperature rise of a thin, ∼2 μm, Pt absorber that is placed in the torus vacuum and exposed, using a pinhole camera, to the full-spectrum of plasma's photon emission. The IRVB installed on C-Mod viewed the poloidal cross section of the core plasma and observed Ohmic and ion cyclotron range of frequency (ICRF)-heated plasmas. Analysis of total radiated power and on-axis emissivity from IRVB is summarized, and quantitative comparisons made to data from both resistive bolometers and AXUV diodes. IRVB results are clearly within a factor of two, but additional effort is needed for it to be used to fully support power exhaust research. The IRVB is shown to be immune to electromagnetic interference from ICRF which strongly impacts C-Mod's resistive bolometers. Results of the bench-top calibration are summarized, including a novel temperature calibration method useful for IRVBs.
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Affiliation(s)
- M L Reinke
- Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830-6286, USA
| | - J L Terry
- MIT Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA
| | - G G van Eden
- Dutch Institute for Fusion Energy, Eindhoven, The Netherlands
| | - B J Peterson
- National Institute for Fusion Science, Toki, Japan
| | - K Mukai
- National Institute for Fusion Science, Toki, Japan
| | - T K Gray
- Oak Ridge National Laboratory, Oak Ridge, Tennessee 37830-6286, USA
| | - B C Stratton
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA
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6
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Hughes JW, Hubbard AE, Mossessian DA, LaBombard B, Biewer TM, Granetz RS, Greenwald M, Hutchinson IH, Irby JH, Lin Y, Marmar ES, Porkolab M, Rice JE, Snipes JA, Terry JL, Wolfe S, Zhurovich K. H-Mode Pedestal and L-H Transition Studies on Alcator C-Mod. Fusion Science and Technology 2017. [DOI: 10.13182/fst07-a1425] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- J. W. Hughes
- Massachusetts Institute of Technology, Plasma Science and Fusion Center, Cambridge Massachusetts 02139
| | - A. E. Hubbard
- Massachusetts Institute of Technology, Plasma Science and Fusion Center, Cambridge Massachusetts 02139
| | - D. A. Mossessian
- Massachusetts Institute of Technology, Plasma Science and Fusion Center, Cambridge Massachusetts 02139
| | - B. LaBombard
- Massachusetts Institute of Technology, Plasma Science and Fusion Center, Cambridge Massachusetts 02139
| | - T. M. Biewer
- Massachusetts Institute of Technology, Plasma Science and Fusion Center, Cambridge Massachusetts 02139
| | - R. S. Granetz
- Massachusetts Institute of Technology, Plasma Science and Fusion Center, Cambridge Massachusetts 02139
| | - M. Greenwald
- Massachusetts Institute of Technology, Plasma Science and Fusion Center, Cambridge Massachusetts 02139
| | - I. H. Hutchinson
- Massachusetts Institute of Technology, Plasma Science and Fusion Center, Cambridge Massachusetts 02139
| | - J. H. Irby
- Massachusetts Institute of Technology, Plasma Science and Fusion Center, Cambridge Massachusetts 02139
| | - Y. Lin
- Massachusetts Institute of Technology, Plasma Science and Fusion Center, Cambridge Massachusetts 02139
| | - E. S. Marmar
- Massachusetts Institute of Technology, Plasma Science and Fusion Center, Cambridge Massachusetts 02139
| | - M. Porkolab
- Massachusetts Institute of Technology, Plasma Science and Fusion Center, Cambridge Massachusetts 02139
| | - J. E. Rice
- Massachusetts Institute of Technology, Plasma Science and Fusion Center, Cambridge Massachusetts 02139
| | - J. A. Snipes
- Massachusetts Institute of Technology, Plasma Science and Fusion Center, Cambridge Massachusetts 02139
| | - J. L. Terry
- Massachusetts Institute of Technology, Plasma Science and Fusion Center, Cambridge Massachusetts 02139
| | - S. Wolfe
- Massachusetts Institute of Technology, Plasma Science and Fusion Center, Cambridge Massachusetts 02139
| | - K. Zhurovich
- Massachusetts Institute of Technology, Plasma Science and Fusion Center, Cambridge Massachusetts 02139
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7
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Affiliation(s)
- J. E. Rice
- Massachusetts Institute of Technology, Plasma Science and Fusion Center Cambridge, Massachusetts 02139-4370
| | - J. L. Terry
- Massachusetts Institute of Technology, Plasma Science and Fusion Center Cambridge, Massachusetts 02139-4370
| | - K. B. Fournier
- Lawrence Livermore National Laboratory, Livermore, California 94550
| | - E. S. Marmar
- Plasma Science and Fusion Center, Massachusetts Institute of Technology Cambridge, Massachusetts 02139-4307
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8
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Terry JL, LaBombard B, Lipschultz B, Greenwald MJ, Rice JE, Zweben SJ. The Scrape-Off Layer in Alcator C-Mod: Transport, Turbulence, and Flows. Fusion Science and Technology 2017. [DOI: 10.13182/fst07-a1426] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- J. L. Terry
- Massachusetts Institute of Technology, Plasma Science and Fusion Center, Cambridge, Massachusetts 02139
| | - B. LaBombard
- Massachusetts Institute of Technology, Plasma Science and Fusion Center, Cambridge, Massachusetts 02139
| | - B. Lipschultz
- Massachusetts Institute of Technology, Plasma Science and Fusion Center, Cambridge, Massachusetts 02139
| | - M. J. Greenwald
- Massachusetts Institute of Technology, Plasma Science and Fusion Center, Cambridge, Massachusetts 02139
| | - J. E. Rice
- Massachusetts Institute of Technology, Plasma Science and Fusion Center, Cambridge, Massachusetts 02139
| | - S. J. Zweben
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543
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9
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Lipschultz B, LaBombard B, Terry JL, Boswell C, Hutchinson IH. Divertor Physics Research on Alcator C-Mod. Fusion Science and Technology 2017. [DOI: 10.13182/fst07-a1428] [Citation(s) in RCA: 77] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- B. Lipschultz
- Massachusetts Institute of Technology, Plasma Science and Fusion Center, Cambridge, Massachusetts 02139
| | - B. LaBombard
- Massachusetts Institute of Technology, Plasma Science and Fusion Center, Cambridge, Massachusetts 02139
| | - J. L. Terry
- Massachusetts Institute of Technology, Plasma Science and Fusion Center, Cambridge, Massachusetts 02139
| | - C. Boswell
- Massachusetts Institute of Technology, Plasma Science and Fusion Center, Cambridge, Massachusetts 02139
| | - I. H. Hutchinson
- Massachusetts Institute of Technology, Plasma Science and Fusion Center, Cambridge, Massachusetts 02139
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10
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Rice JE, Terry JL, Marmar ES, Granetz RS, Greenwald MJ, Hubbard AE, Irby JH, Wolfe SM, Pedersen TS. Impurity Transport in Alcator C-Mod Plasmas. Fusion Science and Technology 2017. [DOI: 10.13182/fst07-a1427] [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] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- J. E. Rice
- Massachusetts Institute of Technology, Plasma Science and Fusion Center Cambridge, Massachusetts 02139-4307
| | - J. L. Terry
- Massachusetts Institute of Technology, Plasma Science and Fusion Center Cambridge, Massachusetts 02139-4307
| | - E. S. Marmar
- Massachusetts Institute of Technology, Plasma Science and Fusion Center Cambridge, Massachusetts 02139-4307
| | - R. S. Granetz
- Massachusetts Institute of Technology, Plasma Science and Fusion Center Cambridge, Massachusetts 02139-4307
| | - M. J. Greenwald
- Massachusetts Institute of Technology, Plasma Science and Fusion Center Cambridge, Massachusetts 02139-4307
| | - A. E. Hubbard
- Massachusetts Institute of Technology, Plasma Science and Fusion Center Cambridge, Massachusetts 02139-4307
| | - J. H. Irby
- Massachusetts Institute of Technology, Plasma Science and Fusion Center Cambridge, Massachusetts 02139-4307
| | - S. M. Wolfe
- Massachusetts Institute of Technology, Plasma Science and Fusion Center Cambridge, Massachusetts 02139-4307
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11
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Affiliation(s)
- B. Lipschultz
- Massachusetts Institute of Technology Plasma Science and Fusion Center, Cambridge Massachusetts 02139
| | - B. LaBombard
- Massachusetts Institute of Technology Plasma Science and Fusion Center, Cambridge Massachusetts 02139
| | - S. Lisgo
- University of Toronto, Institute for Aerospace Studies, Toronto M3H 5T6, Canada
| | - J. L. Terry
- Plasma Science and Fusion Center, Massachusetts Institute of Technology Cambridge Massachusetts 02139
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12
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Basse NP, Dominguez A, Edlund EM, Fiore CL, Granetz RS, Hubbard AE, Hughes JW, Hutchinson IH, Irby JH, LaBombard B, Lin L, Lin Y, Lipschultz B, Liptac JE, Marmar ES, Mossessian DA, Parker RR, Porkolab M, Rice JE, Snipes JA, Tang V, Terry JL, Wolfe SM, Wukitch SJ, Zhurovich K, Bravenec RV, Phillips PE, Rowan WL, Kramer GJ, Schilling G, Scott SD, Zweben SJ. Diagnostic Systems on Alcator C-Mod. Fusion Science and Technology 2017. [DOI: 10.13182/fst07-a1434] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- N. P. Basse
- Massachusetts Institute of Technology, Plasma Science and Fusion Center, Cambridge, Massachusetts 02139
| | - A. Dominguez
- Massachusetts Institute of Technology, Plasma Science and Fusion Center, Cambridge, Massachusetts 02139
| | - E. M. Edlund
- Massachusetts Institute of Technology, Plasma Science and Fusion Center, Cambridge, Massachusetts 02139
| | - C. L. Fiore
- Massachusetts Institute of Technology, Plasma Science and Fusion Center, Cambridge, Massachusetts 02139
| | - R. S. Granetz
- Massachusetts Institute of Technology, Plasma Science and Fusion Center, Cambridge, Massachusetts 02139
| | - A. E. Hubbard
- Massachusetts Institute of Technology, Plasma Science and Fusion Center, Cambridge, Massachusetts 02139
| | - J. W. Hughes
- Massachusetts Institute of Technology, Plasma Science and Fusion Center, Cambridge, Massachusetts 02139
| | - I. H. Hutchinson
- Massachusetts Institute of Technology, Plasma Science and Fusion Center, Cambridge, Massachusetts 02139
| | - J. H. Irby
- Massachusetts Institute of Technology, Plasma Science and Fusion Center, Cambridge, Massachusetts 02139
| | - B. LaBombard
- Massachusetts Institute of Technology, Plasma Science and Fusion Center, Cambridge, Massachusetts 02139
| | - L. Lin
- Massachusetts Institute of Technology, Plasma Science and Fusion Center, Cambridge, Massachusetts 02139
| | - Y. Lin
- Massachusetts Institute of Technology, Plasma Science and Fusion Center, Cambridge, Massachusetts 02139
| | - B. Lipschultz
- Massachusetts Institute of Technology, Plasma Science and Fusion Center, Cambridge, Massachusetts 02139
| | - J. E. Liptac
- Massachusetts Institute of Technology, Plasma Science and Fusion Center, Cambridge, Massachusetts 02139
| | - E. S. Marmar
- Massachusetts Institute of Technology, Plasma Science and Fusion Center, Cambridge, Massachusetts 02139
| | - D. A. Mossessian
- Massachusetts Institute of Technology, Plasma Science and Fusion Center, Cambridge, Massachusetts 02139
| | - R. R. Parker
- Massachusetts Institute of Technology, Plasma Science and Fusion Center, Cambridge, Massachusetts 02139
| | - M. Porkolab
- Massachusetts Institute of Technology, Plasma Science and Fusion Center, Cambridge, Massachusetts 02139
| | - J. E. Rice
- Massachusetts Institute of Technology, Plasma Science and Fusion Center, Cambridge, Massachusetts 02139
| | - J. A. Snipes
- Massachusetts Institute of Technology, Plasma Science and Fusion Center, Cambridge, Massachusetts 02139
| | - V. Tang
- Massachusetts Institute of Technology, Plasma Science and Fusion Center, Cambridge, Massachusetts 02139
| | - J. L. Terry
- Massachusetts Institute of Technology, Plasma Science and Fusion Center, Cambridge, Massachusetts 02139
| | - S. M. Wolfe
- Massachusetts Institute of Technology, Plasma Science and Fusion Center, Cambridge, Massachusetts 02139
| | - S. J. Wukitch
- Massachusetts Institute of Technology, Plasma Science and Fusion Center, Cambridge, Massachusetts 02139
| | - K. Zhurovich
- Massachusetts Institute of Technology, Plasma Science and Fusion Center, Cambridge, Massachusetts 02139
| | - R. V. Bravenec
- Fusion Research Center, University of Texas, Austin, Texas 78712
| | - P. E. Phillips
- Fusion Research Center, University of Texas, Austin, Texas 78712
| | - W. L. Rowan
- Fusion Research Center, University of Texas, Austin, Texas 78712
| | - G. J. Kramer
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543
| | - G. Schilling
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543
| | - S. D. Scott
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543
| | - S. J. Zweben
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543
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13
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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. Rev Sci Instrum 2017; 88:041101. [PMID: 28456269 DOI: 10.1063/1.4981873] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [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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14
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Cziegler I, Hubbard AE, Hughes JW, Terry JL, Tynan GR. Turbulence Nonlinearities Shed Light on Geometric Asymmetry in Tokamak Confinement Transitions. Phys Rev Lett 2017; 118:105003. [PMID: 28339277 DOI: 10.1103/physrevlett.118.105003] [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: 11/01/2016] [Indexed: 06/06/2023]
Abstract
A comprehensive study of fully frequency-resolved nonlinear kinetic energy transfer has been performed for the first time in a diverted tokamak, providing new insight into the parametric dependences of edge turbulence transitions. Measurements using gas puff imaging in the turbulent L-mode state illuminate the source of the long known but as yet unexplained "favorable-unfavorable" geometric asymmetry of the power threshold for transition to the turbulence-suppressed H mode. Results from the recently discovered I mode point to a competition between zonal flow (ZF) and geodesic-acoustic modes (GAM) for turbulent energy, while showing new evidence that the I-to-H transition is still dominated by ZFs. The availability of nonlinear drive for the GAM against net heat flux through the edge corresponds very well to empirical scalings found experimentally for accessing the I mode.
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Affiliation(s)
- I Cziegler
- York Plasma Institute, Department of Physics, University of York, Heslington YO10 5DD, United Kingdom
| | - A E Hubbard
- Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - J W Hughes
- Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - J L Terry
- Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - G R Tynan
- University of California San Diego, La Jolla, California 92093, USA
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15
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Sierchio JM, Cziegler I, Terry JL, White AE, Zweben SJ. Comparison of velocimetry techniques for turbulent structures in gas-puff imaging data. Rev Sci Instrum 2016; 87:023502. [PMID: 26931844 DOI: 10.1063/1.4939672] [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: 06/05/2023]
Abstract
Recent analysis of Gas Puff Imaging (GPI) data from Alcator C-Mod found blob velocities with a modified tracking time delay estimation (TDE). These results disagree with velocity analysis performed using direct Fourier methods. In this paper, the two analysis methods are compared. The implementations of these methods are explained, and direct comparisons using the same GPI data sets are presented to highlight the discrepancies in measured velocities. In order to understand the discrepancies, we present a code that generates synthetic sequences of images that mimic features of the experimental GPI images, with user-specified input values for structure (blob) size and velocity. This allows quantitative comparison of the TDE and Fourier analysis methods, which reveals their strengths and weaknesses. We found that the methods agree for structures of any size as long as all structures move at the same velocity and disagree when there is significant nonlinear dispersion or when structures appear to move in opposite directions. Direct Fourier methods used to extract poloidal velocities give incorrect results when there is a significant radial velocity component and are subject to the barber pole effect. Tracking TDE techniques give incorrect velocity measurements when there are features moving at significantly different speeds or in different directions within the same field of view. Finally, we discuss the limitations and appropriate use of each of methods and applications to the relationship between blob size and velocity.
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Affiliation(s)
- J M Sierchio
- Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - I Cziegler
- Center for Momentum Transport and Flow Organization, University of California, San Diego, La Jolla, California 92093, USA
| | - J L Terry
- Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - A E White
- Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - S J Zweben
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA
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Pace DC, Granetz RS, Vieira R, Bader A, Bosco J, Darrow DS, Fiore C, Irby J, Parker RR, Parkin W, Reinke ML, Terry JL, Wolfe SM, Wukitch SJ, Zweben SJ. Energetic ion loss detector on the Alcator C-Mod tokamak. Rev Sci Instrum 2012; 83:073501. [PMID: 22852689 DOI: 10.1063/1.4731655] [Citation(s) in RCA: 3] [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: 04/19/2012] [Accepted: 06/12/2012] [Indexed: 06/01/2023]
Abstract
A scintillator-based energetic ion loss detector has been successfully commissioned on the Alcator C-Mod tokamak. This probe is located just below the outer midplane, where it captures ions of energies up to 2 MeV resulting from ion cyclotron resonance heating. After passing through a collimating aperture, ions impact different regions of the scintillator according to their gyroradius (energy) and pitch angle. The probe geometry and installation location are determined based on modeling of expected lost ions. The resulting probe is compact and resembles a standard plasma facing tile. Four separate fiber optic cables view different regions of the scintillator to provide phase space resolution. Evolving loss levels are measured during ion cyclotron resonance heating, including variation dependent upon individual antennae.
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Affiliation(s)
- D C Pace
- Oak Ridge Institute for Science and Education, Oak Ridge, Tennessee 37831, USA.
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Abstract
Alcator C-Mod is a particularly challenging environment for thermography. It presents issues that will similarly face ITER, including low-emissivity metal targets, low-Z surface films, and closed divertor geometry. In order to make measurements of the incident divertor heat flux using IR thermography, the C-Mod divertor has been modified and instrumented. A 6° toroidal sector has been given a 2° toroidal ramp in order to eliminate magnetic field-line shadowing by imperfectly aligned divertor tiles. This sector is viewed from above by a toroidally displaced IR camera and is instrumented with thermocouples and calorimeters. The camera provides time histories of surface temperatures that are used to compute incident heat-flux profiles. The camera sensitivity is calibrated in situ using the embedded thermocouples, thus correcting for changes and nonuniformities in surface emissivity due to surface coatings.
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Affiliation(s)
- J L Terry
- Plasma Science and Fusion Center, MIT, Cambridge, Massachusetts 02139, USA.
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Reinke ML, Beiersdorfer P, Howard NT, Magee EW, Podpaly Y, Rice JE, Terry JL. Vacuum ultraviolet impurity spectroscopy on the Alcator C-Mod tokamak. Rev Sci Instrum 2010; 81:10D736. [PMID: 21033927 DOI: 10.1063/1.3494380] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [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
Vacuum ultraviolet spectroscopy is used on the Alcator C-Mod tokamak to study the physics of impurity transport and provide feedback on impurity levels to assist experimental operations. Sputtering from C-Mod's all metal (Mo+W) plasma facing components and ion cyclotron range of frequency antenna and vessel structures (sources for Ti, Fe, Cu, and Ni), the use of boronization for plasma surface conditioning and Ar, Ne, or N(2) gas seeding combine to provide a wealth of spectroscopic data from low-Z to high-Z. Recently, a laser blow-off impurity injector has been added, employing CaF(2) to study core and edge impurity transport. One of the primary tools used to monitor the impurities is a 2.2 m Rowland circle spectrometer utilizing a Reticon array fiber coupled to a microchannel plate. With a 600 lines/mm grating the 80<λ<1050 Å range can be scanned, although only 40-100 Å can be observed for a single discharge. Recently, a flat-field grating spectrometer was installed which utilizes a varied line spacing grating to image the spectrum to a soft x-ray sensitive Princeton Instruments charge-coupled device camera. Using a 2400 lines/mm grating, the 10<λ<70 Å range can be scanned with 5-6 nm observed for a single discharge. A variety of results from recent experiments are shown that highlight the capability to track a wide range of impurities.
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Affiliation(s)
- M L Reinke
- Plasma Science and Fusion Center, MIT, Cambridge, Massachusetts 02139, USA.
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Fournier KB, Cohen M, Goldstein WH, Osterheld AL, Finkenthal M, May MJ, Terry JL, Graf MA, Rice J. Dielectronic recombination and excitation autoionization rate coefficients for potassiumlike Mo23+ to fluorinelike Mo33+. Phys Rev A 1996; 54:3870-3884. [PMID: 9913934 DOI: 10.1103/physreva.54.3870] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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Rice JE, Fournier KB, Terry JL, Graf MA, Finkenthal M, Marmar ES, Goldstein WH. X-ray observations of 2l-nl' transitions from Zr, Nb, Mo, and Pd in near-neonlike charge states. Phys Rev A 1996; 53:3953-3962. [PMID: 9913357 DOI: 10.1103/physreva.53.3953] [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: 05/22/2023]
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Fournier KB, Goldstein WH, May M, Finkenthal M, Terry JL. Resonant excitation channels in the 3d10-3d94s and 3d10-3d94p transitions of nickel-like Mo14+ and Zr12+. Phys Rev A 1996; 53:3110-3116. [PMID: 9913250 DOI: 10.1103/physreva.53.3110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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Jassby DL, Barnes CW, Bell MG, Bitter M, Boivin R, Bretz NL, Budny RV, Bush CE, Dylla HF, Efthimion PC, Fredrickson ED, Hawryluk RJ, Hill KW, Hosea J, Hsuan H, Janos AC, Jobes FC, Johnson DW, Johnson LC, Kamperschroer J, Kieras‐Phillips C, Kilpatrick SJ, LaMarche PH, LeBlanc B, Mansfield DK, Marmar ES, McCune DC, McGuire KM, Meade DM, Medley SS, Mikkelsen DR, Mueller D, Owens DK, Park HK, Paul SF, Pitcher S, Ramsey AT, Redi MH, Sabbagh SA, Scott SD, Snipes J, Stevens J, Strachan JD, Stratton BC, Synakowski EJ, Taylor G, Terry JL, Timberlake JR, Towner HH, Ulrickson M, von Goeler S, Wieland RM, Williams M, Wilson JR, Wong K, Young KM, Zarnstorff MC, Zweben SJ. High‐Qplasmas in the TFTR tokamak. ACTA ACUST UNITED AC 1991. [DOI: 10.1063/1.859988] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [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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Benjamin RD, Terry JL, Moos HW. Poloidal rotation velocities in the outer half of Alcator-C plasmas. Phys Rev A 1990; 41:1034-1040. [PMID: 9903186 DOI: 10.1103/physreva.41.1034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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Benjamin RD, Terry JL, Moos HW. Contribution of the Zeeman effect to measured line profiles emitted by Alcator-C plasmas. Phys Rev A Gen Phys 1988; 37:537-542. [PMID: 9899683 DOI: 10.1103/physreva.37.537] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Benjamin RD, Terry JL, Moos HW. Identification of a forbidden line in Kr XXIII. Phys Rev A Gen Phys 1987; 36:4504-4506. [PMID: 9899412 DOI: 10.1103/physreva.36.4504] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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Petrasso RD, Sigmar DJ, Wenzel KW, Hopf JE, Greenwald M, Terry JL, Parker J. Observations of centrally peaked impurity profiles following pellet injection in the Alcator-C tokamak. Phys Rev Lett 1986; 57:707-710. [PMID: 10034137 DOI: 10.1103/physrevlett.57.707] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [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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Knowlton S, Porkolab M, Takase Y, Texter S, Bonoli P, Fiore C, McCool S, McDermott FS, Terry JL. Energy confinement of lower-hybrid-current-driven tokamak plasmas. Phys Rev Lett 1986; 57:587-590. [PMID: 10034100 DOI: 10.1103/physrevlett.57.587] [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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Rice JE, Marmar ES, Terry JL, Kallne E, Kallne J. Observation of charge-transfer population of high-n levels in Ar+16 from neutral hydrogen in the ground and excited states in a tokamak plasma. Phys Rev Lett 1986; 56:50-53. [PMID: 10032526 DOI: 10.1103/physrevlett.56.50] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [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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Moos HW, Chen KI, Terry JL, Fastie WG. Construction, calibration, and application of a compact spectrophotometer for EUV (300-2500-A) plasma diagnostics. Appl Opt 1979; 18:1209-1216. [PMID: 20208909 DOI: 10.1364/ao.18.001209] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
A 400-mm normal incidence concave grating spectrophotometer, specifically designed for plasma diagnostics, is described. The wavelength drive, in which the grating is translated as well as rotated, is discussed in detail; the wavelength linearity of the sine drive and methods of improving it are analyzed. The instrument can be used in any orientation, is portable under vacuum, and quite rugged. The construction techniques utilized produce a high quality vacuum making the instrument compatible with both high purity plasma devices and synchrotron radiation sources. The photometric sensitivity calibration was found to be very stable during extended use on high temperature plasma devices. The applications of the instrument to diagnose plasmas in two tokamaks and a mirror device are described. A facility used for photometric calibration of extreme ultraviolet (lambda > 300-A) spectrophotometers against NBS standard diodes is described. The instrumental calibration obtained using this facility was checked by using synchrotron radiation from SURF II; very good agreement was observed.
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Porterfield HW, Terry JL, Trabue JC, Perrin ER. Elective reconstructive surgery of the breast. Ohio State Med J 1969; 65:32-6. [PMID: 5762389] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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Terry JL. Facial scars. S D J Med 1967; 20:19-24. [PMID: 5232112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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