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Leppink E, Lau C, Lin Y, Wukitch SJ. Evaluation of the Abel inversion integral in O-mode plasma reflectometry using Chebyshev-Gauss quadrature. Rev Sci Instrum 2023; 94:063506. [PMID: 37862546 DOI: 10.1063/5.0132246] [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: 10/27/2022] [Accepted: 06/15/2023] [Indexed: 10/22/2023]
Abstract
The Abel transform is often used to reconstruct plasma density profiles from O-Mode polarized reflectometry diagnostics. However, standard numerical trapezoidal evaluation of the Abel inversion integral can be computationally expensive for a large number of evaluation points, and an endpoint singularity exists on the upper-bound of the integral, which can result in an increased error. In this work, Chebyshev-Gauss quadrature is introduced as a new method to evaluate the Abel inversion integral for the problem of O-Mode plasma reflectometry. The method does not require numerical evaluation of an integral singularity and is shown to have similar accuracy compared to existing methods while being computationally efficient.
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Affiliation(s)
- E Leppink
- MIT Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA
| | - C Lau
- Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - Y Lin
- MIT Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA
| | - S J Wukitch
- MIT Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA
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2
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Seltzman AH, Wukitch SJ. Precipitate Size in GRCop-42 and GRCop-84 Cu-Cr-Nb Alloy Gas Atomized Powder and L-PBF Additive Manufactured Material. Fusion Science and Technology 2023. [DOI: 10.1080/15361055.2022.2147765] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- A. H. Seltzman
- Massachusetts Institute of Technology, Plasma Science and Fusion Center, 190 Albany Street, Cambridge, Massachusetts 02139
| | - S. J. Wukitch
- Massachusetts Institute of Technology, Plasma Science and Fusion Center, 190 Albany Street, Cambridge, Massachusetts 02139
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3
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Seltzman AH, Wukitch SJ. Precipitate Size in GRCop-84 Gas Atomized Powder and Laser Powder Bed Fusion Additively Manufactured Material. Fusion Science and Technology 2021. [DOI: 10.1080/15361055.2021.1913030] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- A. H. Seltzman
- Massachusetts Institute of Technology, Plasma Science and Fusion Center, 190 Albany Street, Cambridge, Massachusetts 02139
| | - S. J. Wukitch
- Massachusetts Institute of Technology, Plasma Science and Fusion Center, 190 Albany Street, Cambridge, Massachusetts 02139
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4
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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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5
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Bonoli PT, Parker R, Wukitch SJ, Lin Y, Porkolab M, Wright JC, Edlund E, Graves T, Lin L, Liptac J, Parisot A, Schmidt AE, Tang V, Beck W, Childs R, Grimes M, Gwinn D, Johnson D, Irby J, Kanojia A, Koert P, Marazita S, Marmar E, Terry D, Vieira R, Wallace G, Zaks J, Bernabei S, Brunkhorse C, Ellis R, Fredd E, Greenough N, Hosea J, Kung CC, Loesser GD, Rushinski J, Schilling G, Phillips CK, Wilson JR, Harvey RW, Fiore CL, Granetz R, Greenwald M, Hubbard AE, Hutchinson IH, Labombard B, Lipschultz B, Rice J, Snipes JA, Terry J, Wolfe SM. Wave-Particle Studies in the Ion Cyclotron and Lower Hybrid Ranges of Frequencies in Alcator C-Mod. Fusion Science and Technology 2017. [DOI: 10.13182/fst07-a1430] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [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)
- P. T. Bonoli
- Massachusetts Institute of Technology, Plasma Science and Fusion Center, Cambridge, Massachusetts 02139
| | - R. Parker
- 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
| | - Y. Lin
- 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. C. Wright
- Massachusetts Institute of Technology, Plasma Science and Fusion Center, Cambridge, Massachusetts 02139
| | - E. Edlund
- Massachusetts Institute of Technology, Plasma Science and Fusion Center, Cambridge, Massachusetts 02139
| | - T. Graves
- 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
| | - J. Liptac
- Massachusetts Institute of Technology, Plasma Science and Fusion Center, Cambridge, Massachusetts 02139
| | - A. Parisot
- Massachusetts Institute of Technology, Plasma Science and Fusion Center, Cambridge, Massachusetts 02139
| | - A. E. Schmidt
- 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
| | - W. Beck
- Massachusetts Institute of Technology, Plasma Science and Fusion Center, Cambridge, Massachusetts 02139
| | - R. Childs
- Massachusetts Institute of Technology, Plasma Science and Fusion Center, Cambridge, Massachusetts 02139
| | - M. Grimes
- Massachusetts Institute of Technology, Plasma Science and Fusion Center, Cambridge, Massachusetts 02139
| | - D. Gwinn
- Massachusetts Institute of Technology, Plasma Science and Fusion Center, Cambridge, Massachusetts 02139
| | - D. Johnson
- Massachusetts Institute of Technology, Plasma Science and Fusion Center, Cambridge, Massachusetts 02139
| | - J. Irby
- Massachusetts Institute of Technology, Plasma Science and Fusion Center, Cambridge, Massachusetts 02139
| | - A. Kanojia
- Massachusetts Institute of Technology, Plasma Science and Fusion Center, Cambridge, Massachusetts 02139
| | - P. Koert
- Massachusetts Institute of Technology, Plasma Science and Fusion Center, Cambridge, Massachusetts 02139
| | - S. Marazita
- Massachusetts Institute of Technology, Plasma Science and Fusion Center, Cambridge, Massachusetts 02139
| | - E. Marmar
- Massachusetts Institute of Technology, Plasma Science and Fusion Center, Cambridge, Massachusetts 02139
| | - D. Terry
- Massachusetts Institute of Technology, Plasma Science and Fusion Center, Cambridge, Massachusetts 02139
| | - R. Vieira
- Massachusetts Institute of Technology, Plasma Science and Fusion Center, Cambridge, Massachusetts 02139
| | - G. Wallace
- Massachusetts Institute of Technology, Plasma Science and Fusion Center, Cambridge, Massachusetts 02139
| | - J. Zaks
- Massachusetts Institute of Technology, Plasma Science and Fusion Center, Cambridge, Massachusetts 02139
| | - S. Bernabei
- Princeton University, Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543
| | - C. Brunkhorse
- Princeton University, Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543
| | - R. Ellis
- Princeton University, Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543
| | - E. Fredd
- Princeton University, Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543
| | - N. Greenough
- Princeton University, Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543
| | - J. Hosea
- Princeton University, Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543
| | - C. C. Kung
- Princeton University, Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543
| | - G. D. Loesser
- Princeton University, Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543
| | - J. Rushinski
- Princeton University, Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543
| | - G. Schilling
- Princeton University, Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543
| | - C. K. Phillips
- Princeton University, Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543
| | - J. R. Wilson
- Princeton University, Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543
| | | | - C. L. Fiore
- Massachusetts Institute of Technology, Plasma Science and Fusion Center, Cambridge, Massachusetts 02139
| | - R. 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
| | - A. E. Hubbard
- 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
| | - 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
| | - J. 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. 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
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Rice JE, Marmar ES, Bonoli PT, Granetz RS, Greenwald MJ, Hubbard AE, Hughes JW, Hutchinson IH, Irby JH, LaBombard B, Lee WD, Lin Y, Mossessian D, Snipes JA, Wolfe SM, Wukitch SJ. Spontaneous Toroidal Rotation in Alcator C-Mod Plasmas with No Momentum Input. Fusion Science and Technology 2017. [DOI: 10.13182/fst07-a1423] [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
| | - E. S. Marmar
- Massachusetts Institute of Technology, Plasma Science and Fusion Center, Cambridge, Massachusetts 02139-4307
| | - P. T. Bonoli
- 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. W. Hughes
- Massachusetts Institute of Technology, Plasma Science and Fusion Center, Cambridge, Massachusetts 02139-4307
| | - I. H. Hutchinson
- 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
| | - B. LaBombard
- Massachusetts Institute of Technology, Plasma Science and Fusion Center, Cambridge, Massachusetts 02139-4307
| | - W. D. Lee
- Massachusetts Institute of Technology, Plasma Science and Fusion Center, Cambridge, Massachusetts 02139-4307
| | - Y. Lin
- Massachusetts Institute of Technology, Plasma Science and Fusion Center, Cambridge, Massachusetts 02139-4307
| | - D. Mossessian
- Massachusetts Institute of Technology, Plasma Science and Fusion Center, Cambridge, Massachusetts 02139-4307
| | - J. A. Snipes
- 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
| | - S. J. Wukitch
- Massachusetts Institute of Technology, Plasma Science and Fusion Center, Cambridge, Massachusetts 02139-4307
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7
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Fiore CL, Ernst DR, Rice JE, Zhurovich K, Basse N, Bonoli PT, Greenwald MJ, Marmar ES, Wukitch SJ. Internal Transport Barriers in Alcator C-Mod. Fusion Science and Technology 2017. [DOI: 10.13182/fst07-a1424] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [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)
- C. L. Fiore
- Massachusetts Institute of Technology Plasma Science and Fusion Center, Cambridge, Massachusetts 02139
| | - D. R. Ernst
- 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
| | - K. Zhurovich
- Massachusetts Institute of Technology Plasma Science and Fusion Center, Cambridge, Massachusetts 02139
| | - N. Basse
- Massachusetts Institute of Technology Plasma Science and Fusion Center, Cambridge, Massachusetts 02139
| | - P. T. Bonoli
- 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
| | - E. S. Marmar
- 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
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8
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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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White AE, Hubbard AE, Hughes JW, Bonoli PT, Austin ME, Bader A, Harvey RW, Lin Y, Ma Y, Reinke ML, Wolfe SM, Wukitch SJ. Survey of the TS-ECE Discrepancy and recent investigations in ICRF heated plasmas at Alcator C-Mod. EPJ Web of Conferences 2012. [DOI: 10.1051/epjconf/20123203009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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10
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Edlund EM, Porkolab M, Kramer GJ, Lin L, Lin Y, Wukitch SJ. Observation of reversed shear Alfvén eigenmodes between sawtooth crashes in the Alcator C-Mod tokamak. Phys Rev Lett 2009; 102:165003. [PMID: 19518719 DOI: 10.1103/physrevlett.102.165003] [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: 05/30/2008] [Indexed: 05/27/2023]
Abstract
Groups of frequency chirping modes observed between sawtooth crashes in the Alcator C-Mod tokamak are interpreted as reversed shear Alfvén eigenmodes near the q=1 surface. These modes indicate that a reversed shear q profile is generated during the relaxation phase of the sawtooth cycle. Two important parameters, q_{min} and its radial position, are deduced from comparisons of measured density fluctuations with calculations from the ideal MHD code NOVA. These studies provide valuable constraints for further modeling of the sawtooth cycle.
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Affiliation(s)
- E M Edlund
- MIT Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA
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11
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Lin Y, Rice JE, Wukitch SJ, Greenwald MJ, Hubbard AE, Ince-Cushman A, Lin L, Porkolab M, Reinke ML, Tsujii N. Observation of ion-cyclotron-frequency mode-conversion flow drive in tokamak plasmas. Phys Rev Lett 2008; 101:235002. [PMID: 19113561 DOI: 10.1103/physrevlett.101.235002] [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] [Received: 06/30/2008] [Indexed: 05/27/2023]
Abstract
Strong toroidal flow (Vphi) and poloidal flow (Vtheta) have been observed in D-3He plasmas with ion cyclotron range of frequencies (ICRF) mode-conversion (MC) heating on the Alcator C-Mod tokamak. The toroidal flow scales with the rf power Prf (up to 30 km/s per MW), and is significantly larger than that in ICRF minority heated plasmas at the same rf power or stored energy. The central Vphi responds to Prf faster than the outer regions, and the Vphi(r) profile is broadly peaked for r/a < or =0.5. Localized (0.3 < or = r/a < or =0.5) Vtheta appears when Prf > or =1.5 MW and increases with power (up to 0.7 km/s per MW). The experimental evidence together with numerical wave modeling suggests a local flow drive source due to the interaction between the MC ion cyclotron wave and 3He ions.
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Affiliation(s)
- Y Lin
- Massachusetts Institute of Technology, Plasma Science and Fusion Center, Cambridge, Massachusetts 02139, USA.
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12
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Hanson GR, Wilgen JB, Lau C, Lin Y, Wallace GM, Wukitch SJ. Scrape-off layer reflectometer for Alcator C-Mod. Rev Sci Instrum 2008; 79:10F114. [PMID: 19044598 DOI: 10.1063/1.2966460] [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: 05/27/2023]
Abstract
A two-frequency x-mode reflectometer operating from 100 to 146 GHz is deployed on Alcator C-Mod to measure the density profile and fluctuations in the scrape-off layer (SOL) immediately in front of the new J-port ICRF antenna and the new C-port lower hybrid launcher. The reflectometer covers densities from 10(16) to 10(20) m(-3) at 5-5.4 T. To provide the greatest flexibility and capability to deal with density fluctuations approaching 100% peak-to-peak in the SOL, both full-phase and differential-phase measurement capabilities with sweep speeds of approximately 10 micros to >1 ms are implemented. The differential-phase measurement uses a difference frequency of 500 MHz, corresponding to cutoff layer separations ranging from about 0.1 to 1 mm. The reflectometer has six sets of launchers: three on the ICRF antenna and three on the lower hybrid launcher. Both the ICRF antenna and the lower hybrid launcher incorporate reflectometer antennas at their top, bottom, and midplane locations.
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Affiliation(s)
- G R Hanson
- Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
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13
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Nelson-Melby E, Porkolab M, Bonoli PT, Lin Y, Mazurenko A, Wukitch SJ. Experimental observations of mode-converted ion cyclotron waves in a tokamak plasma by phase contrast imaging. Phys Rev Lett 2003; 90:155004. [PMID: 12732043 DOI: 10.1103/physrevlett.90.155004] [Citation(s) in RCA: 5] [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] [Received: 09/13/2002] [Indexed: 05/24/2023]
Abstract
The process of mode conversion, whereby an externally launched electromagnetic wave converts into a shorter wavelength mode(s) in a thermal plasma near a resonance in the index of refraction, is particularly important in a multi-ion species plasma near the ion cyclotron frequency. Using phase contrast imaging techniques (PCI), mode-converted electromagnetic ion cyclotron waves have been detected for the first time in the Alcator C-Mod tokamak near the H-3He ion-ion hybrid resonance region during high power rf heating experiments. The results agree with theoretical predictions.
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Affiliation(s)
- E Nelson-Melby
- Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
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14
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Catchen GL, Williams ID, Spaar DM, Wukitch SJ, Adams JM. Highly asymmetric electric-field gradients at the Nb sites in ferroelastic GdNbO4 and NdNbO4. Phys Rev B Condens Matter 1991; 43:1138-1141. [PMID: 9996307 DOI: 10.1103/physrevb.43.1138] [Citation(s) in RCA: 5] [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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15
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Catchen GL, Wukitch SJ, Spaar DM, Blaszkiewicz M. Temperature dependence of the nuclear quadrupole interactions at Ti sites in ferroelectric PbTiO3 and in ilmenite and perovskite CdTiO3: Evidence for order-disorder phenomena. Phys Rev B Condens Matter 1990; 42:1885-1894. [PMID: 9995629 DOI: 10.1103/physrevb.42.1885] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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