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Zamperini S, Abrams T, Nichols JH, Elder JD, Duran JD, Stangeby PC, Donovan DC, Rudakov DL, Wingen A, Crowe C. Separatrix-to-Wall Simulations of Impurity Transport with a Fully Three-Dimensional Wall in DIII-D. Fusion Science and Technology 2022. [DOI: 10.1080/15361055.2022.2082791] [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: 11/04/2022]
Affiliation(s)
| | - T. Abrams
- General Atomics, San Diego, California
| | | | - J. D. Elder
- University of Toronto, Institute for Aerospace Studies, Toronto, Ontario, Canada
| | - J. D. Duran
- University of Tennessee, Knoxville, Department of Nuclear Engineering, Knoxville, Tennessee
| | - P. C. Stangeby
- University of Toronto, Institute for Aerospace Studies, Toronto, Ontario, Canada
| | - D. C. Donovan
- University of Tennessee, Knoxville, Department of Nuclear Engineering, Knoxville, Tennessee
| | - D. L. Rudakov
- University of California, San Diego, Center for Energy Research, San Diego California
| | - A. Wingen
- Oak Ridge National Laboratory, Oak Ridge, Tennessee
| | - C. Crowe
- General Atomics, San Diego, California
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Donovan DC, Unterberg EA, Stangeby PC, Zamperini S, Auxier JD, Rudakov DL, Wampler WR, Zach M, Abrams T, Duran JD, Elder JD, Neff AL. Utilization of outer-midplane collector probes with isotopically enriched tungsten tracer particles for impurity transport studies in the scrape-off layer of DIII-D (invited). Rev Sci Instrum 2018; 89:10I115. [PMID: 30399941 DOI: 10.1063/1.5039347] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2018] [Accepted: 06/13/2018] [Indexed: 06/08/2023]
Abstract
Triplet sets of replaceable graphite rod collector probes (CPs), each with collection surfaces on opposing faces and oriented normal to the magnetic field, were inserted at the outboard mid-plane of DIII-D to study divertor tungsten (W) transport in the Scrape-Off Layer (SOL). Each CP collects particles along field lines with different parallel sampling lengths (determined by the rod diameters and SOL transport) giving radial profiles from the main wall inward to R-R sep ∼ 6 cm. The CPs were deployed in a first-of-a-kind experiment using two toroidal rings of distinguishable isotopically enriched, W-coated divertor tiles installed at 2 poloidal locations in the divertor. Post-mortem Rutherford backscatter spectrometry of the surface of the CPs provided areal density profiles of elemental W coverage. Higher W content was measured on the probe side facing along the field lines toward the inner target indicating higher concentration of W in the plasma upstream of the CP, even though the W-coated rings were in the outer target region of the divertor. Inductively coupled plasma mass spectroscopy validates the isotopic tracer technique through analysis of CPs exposed during L-mode discharges with the outer strike point on the isotopically enriched W coated-tile ring. The contribution from each divertor ring of W to the deposition profiles found on the mid-plane collector probes was able to be de-convoluted using a stable isotope mixing model. The results provided quantitative information on the W source and transport from specific poloidal locations within the lower divertor region.
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Affiliation(s)
- D C Donovan
- Department of Nuclear Engineering, University of Tennessee-Knoxville, Knoxville, Tennessee 37916, USA
| | - E A Unterberg
- Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - P C Stangeby
- Institute for Aerospace Studies, University of Toronto, North York, Ontario M3H 5T6, Canada
| | - S Zamperini
- Department of Nuclear Engineering, University of Tennessee-Knoxville, Knoxville, Tennessee 37916, USA
| | - J D Auxier
- Department of Nuclear Engineering, University of Tennessee-Knoxville, Knoxville, Tennessee 37916, USA
| | - D L Rudakov
- Center for Energy Research, University of California-San Diego, San Diego, California 92093, USA
| | - W R Wampler
- Sandia National Laboratory, Albuquerque, New Mexico 87123, USA
| | - M Zach
- Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
| | - T Abrams
- General Atomics, 3483 Dunhill Street, San Diego, California 92121, USA
| | - J D Duran
- Department of Nuclear Engineering, University of Tennessee-Knoxville, Knoxville, Tennessee 37916, USA
| | - J D Elder
- Institute for Aerospace Studies, University of Toronto, North York, Ontario M3H 5T6, Canada
| | - A L Neff
- Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
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3
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Boivin RL, Luxon JL, Austin ME, Brooks NH, Burrell KH, Doyle EJ, Fenstermacher ME, Gray DS, Groth M, Hsieh CL, Jayakumar RJ, Lasnier CJ, Leonard AW, McKee GR, Moyer RA, Rhodes TL, Rost JC, Rudakov DL, Schaffer MJ, Strait EJ, Thomas DM, Van Zeeland M, Watkins JG, Watson GW, Wong CPC. DIII-D Diagnostic Systems. Fusion Science and Technology 2017. [DOI: 10.13182/fst05-a1043] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [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)
| | | | - M. E. Austin
- General Atomics, P.O. Box 85608, San Diego, California 92186-5608
- University of Texas–Austin, Austin, Texas
| | | | | | - E. J. Doyle
- General Atomics, P.O. Box 85608, San Diego, California 92186-5608
- University of California–Los Angeles, Los Angeles, California
| | - M. E. Fenstermacher
- General Atomics, P.O. Box 85608, San Diego, California 92186-5608
- Lawrence Livermore National Laboratory, Livermore, California/University of California–Los Angeles, Los Angeles, California
| | - D. S. Gray
- General Atomics, P.O. Box 85608, San Diego, California 92186-5608
- University of California–San Diego, La Jolla, California
| | - M. Groth
- General Atomics, P.O. Box 85608, San Diego, California 92186-5608
- Lawrence Livermore National Laboratory, Livermore, California/University of California–Los Angeles, Los Angeles, California
| | | | - R. J. Jayakumar
- General Atomics, P.O. Box 85608, San Diego, California 92186-5608
- Lawrence Livermore National Laboratory, Livermore, California/University of California–Los Angeles, Los Angeles, California
| | - C. J. Lasnier
- General Atomics, P.O. Box 85608, San Diego, California 92186-5608
- Lawrence Livermore National Laboratory, Livermore, California/University of California–Los Angeles, Los Angeles, California
| | | | - G. R. McKee
- General Atomics, P.O. Box 85608, San Diego, California 92186-5608
- University of Wisconsin–Madison, Madison, Wisconsin
| | - R. A. Moyer
- General Atomics, P.O. Box 85608, San Diego, California 92186-5608
- University of California–San Diego, La Jolla, California
| | - T. L. Rhodes
- General Atomics, P.O. Box 85608, San Diego, California 92186-5608
- University of California–Los Angeles, Los Angeles, California
| | - J. C. Rost
- General Atomics, P.O. Box 85608, San Diego, California 92186-5608
- Massachusetts Institute of Technology, Cambridge, Massachusetts
| | - D. L. Rudakov
- General Atomics, P.O. Box 85608, San Diego, California 92186-5608
- University of California–San Diego, La Jolla, California
| | | | | | | | - M. Van Zeeland
- General Atomics, P.O. Box 85608, San Diego, California 92186-5608
- University of Wisconsin–Madison, Madison, Wisconsin
| | - J. G. Watkins
- General Atomics, P.O. Box 85608, San Diego, California 92186-5608
- Sandia National Laboratories, Albuquerque, New Mexico
| | - G. W. Watson
- General Atomics, P.O. Box 85608, San Diego, California 92186-5608
- University of California–Irvine, Irvine, California
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Lasnier CJ, Allen SL, Boedo JA, Groth M, Brooks NH, McLean A, LaBombard B, Skinner CH, Rudakov DL, West WP, Wong CPC. Chapter 10: First Wall and Operational Diagnostics. Fusion Science and Technology 2017. [DOI: 10.13182/fst08-a1682] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [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)
- C. J. Lasnier
- Lawrence Livermore National Laboratory, Livermore, California 94550
| | - S. L. Allen
- Lawrence Livermore National Laboratory, Livermore, California 94550
| | - J. A. Boedo
- University of California, San Diego, California 92093
| | - M. Groth
- Lawrence Livermore National Laboratory, Livermore, California 94550
| | - N. H. Brooks
- General Atomics, P.O. Box 85608, San Diego, California 92186-5608
| | - A. McLean
- University of Toronto, Toronto, Ontario M3H 5T6, Canada
| | - B. LaBombard
- Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
| | - C. H. Skinner
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543
| | - D. L. Rudakov
- University of California, San Diego, California 92093
| | - W. P. West
- General Atomics, P.O. Box 85608, San Diego, California 92186-5608
| | - C. P. C. Wong
- General Atomics, P.O. Box 85608, San Diego, California 92186-5608
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Litnovsky A, Matveeva M, Rudakov DL, Chrobak CP, Allen SL, Leonard AW, Taylor PL, Wong CPC, Fitzpatrick BWN, Davis JW, Haasz AA, Stangeby PC, Breuer U, Philipps V, MÖller S. Impact of Thermo-Oxidative Wall Conditioning on the Performance of Diagnostic Mirrors for ITER. Fusion Science and Technology 2017. [DOI: 10.13182/fst12-a14119] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [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)
- A. Litnovsky
- Institute of Energy and Climate Research-Plasma Physics, Forschungszentrum Jülich GmbH Association EURATOM-FZJ, Partner in the Trilateral Euregio Cluster, Jülich, Germany
| | - M. Matveeva
- Institute of Energy and Climate Research-Plasma Physics, Forschungszentrum Jülich GmbH Association EURATOM-FZJ, Partner in the Trilateral Euregio Cluster, Jülich, Germany
| | - D. L. Rudakov
- University of California, San Diego, La Jolla, California 92093-0417, USA
| | - C. P. Chrobak
- General Atomics, San Diego, California 92186-5608, USA
| | - S. L. Allen
- Lawrence Livermore National Laboratory, Livermore, California, USA
| | - A. W. Leonard
- General Atomics, San Diego, California 92186-5608, USA
| | - P. L. Taylor
- General Atomics, San Diego, California 92186-5608, USA
| | - C. P. C. Wong
- General Atomics, San Diego, California 92186-5608, USA
| | - B. W. N. Fitzpatrick
- University of Toronto, Institute for Aerospace Studies, Toronto, Ontario M3H 5T6, Canada
| | - J. W. Davis
- University of Toronto, Institute for Aerospace Studies, Toronto, Ontario M3H 5T6, Canada
| | - A. A. Haasz
- University of Toronto, Institute for Aerospace Studies, Toronto, Ontario M3H 5T6, Canada
| | - P. C. Stangeby
- University of Toronto, Institute for Aerospace Studies, Toronto, Ontario M3H 5T6, Canada
| | - U. Breuer
- Central Division of Analytical Chemistry, Forschungszentrum Jülich, D 52425 Jülich, Germany
| | - V. Philipps
- Institute of Energy and Climate Research-Plasma Physics, Forschungszentrum Jülich GmbH Association EURATOM-FZJ, Partner in the Trilateral Euregio Cluster, Jülich, Germany
| | - S. MÖller
- Institute of Energy and Climate Research-Plasma Physics, Forschungszentrum Jülich GmbH Association EURATOM-FZJ, Partner in the Trilateral Euregio Cluster, Jülich, Germany
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Boedo JA, Rudakov DL. Estimation of plasma ion saturation current and reduced tip arcing using Langmuir probe harmonics. Rev Sci Instrum 2017; 88:033505. [PMID: 28372379 DOI: 10.1063/1.4978453] [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: 06/07/2023]
Abstract
We present a method to calculate the ion saturation current, Isat, for Langmuir probes at high frequency (>100 kHz) using the harmonics technique and we compare that to a direct measurement of Isat. It is noted that the Isat estimation can be made directly by the ratio of harmonic amplitudes, without explicitly calculating Te. We also demonstrate that since the probe tips using the harmonic method are oscillating near the floating potential, drawing little power, this method reduces tip heating and arcing and allows plasma density measurements at a plasma power flux that would cause continuously biased tips to arc. A multi-probe array is used, with two spatially separated tips employing the harmonics technique and measuring the amplitude of at least two harmonics per tip. A third tip, located between the other two, measures the ion saturation current directly. We compare the measured and calculated ion saturation currents for a variety of plasma conditions and demonstrate the validity of the technique and its use in reducing arcs.
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Affiliation(s)
- J A Boedo
- Center for Energy Research, University of California, San Diego, La Jolla, California 92093-0417, USA
| | - D L Rudakov
- Center for Energy Research, University of California, San Diego, La Jolla, California 92093-0417, USA
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Müller SH, Boedo JA, Burrell KH, DeGrassie JS, Moyer RA, Rudakov DL, Solomon WM. Experimental investigation of the role of fluid turbulent stresses and edge plasma flows for intrinsic rotation generation in DIII-D H-mode plasmas. Phys Rev Lett 2011; 106:115001. [PMID: 21469867 DOI: 10.1103/physrevlett.106.115001] [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: 11/24/2010] [Indexed: 05/30/2023]
Abstract
The first measurements of turbulent stresses and flows inside the separatrix of a tokamak H-mode plasma are reported, using a reciprocating multitip Langmuir probe at the DIII-D tokamak. A strong co-current rotation layer at the separatrix is found to precede intrinsic rotation development in the core. The measured fluid turbulent stresses transport toroidal momentum outward against the velocity gradient and thus try to sustain the edge layer. However, large kinetic stresses must exist to explain the net inward momentum transport leading to co-current core plasma rotation. The importance of such kinetic stresses is corroborated by the success of a simple orbit loss model, representing a purely kinetic mechanism, in the prediction of features of the edge corotation layer.
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Affiliation(s)
- S H Müller
- Center for Energy Research, University of California of San Diego, 9500 Gilman Drive, M/C 0417, La Jolla, California 92093, USA
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McLean AG, Davis JW, Stangeby PC, Brooks NH, Ellis RM, Haasz AA, Rudakov DL, West WP, Whyte DG, Wong CPC. Porous plug gas injection systems for studies of hydrocarbon dissociation and transport in the DIII-D tokamak. Rev Sci Instrum 2009; 80:043501. [PMID: 19405654 DOI: 10.1063/1.3100180] [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: 05/27/2023]
Abstract
A probe has been designed, constructed, and successfully used to inject methane into the DIII-D lower divertor in a manner imitating natural release by chemical erosion. This porous plug injector (PPI) probe consists of a self-contained gas reservoir with an integrated pressure gauge and a 3 cm diameter porous surface through which gas is injected into the lower divertor of the tokamak. The probe is positioned flush with the divertor target surface by means of the divertor materials evaluation system. Two gas delivery systems were developed: in the first, gas flow is regulated by a remotely controlled microvalve and in the second by a fixed micro-orifice flow restrictor. Because of the large area of the porous surface through which gas is admitted, the injected hydrocarbon molecules see a local carbon surface (>90% carbon) similar to that seen by hydrocarbons being emitted by chemical sputtering from surrounding carbon tiles. The distributed gas source also reduces the disturbance to the local plasma while providing sufficient signal for spectroscopic detection. In situ spectroscopic measurements with the PPI in DIII-D allow the direct calibration of response for measured plasma conditions from a known influx of gas.
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Affiliation(s)
- A G McLean
- Institute for Aerospace Studies, University of Toronto, 4925 Dufferin St., Toronto, Ontario M3H 5T6, Canada.
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9
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Rudakov DL, Yu JH, Boedo JA, Hollmann EM, Krasheninnikov SI, Moyer RA, Muller SH, Pigarov AY, Rosenberg M, Smirnov RD, West WP, Boivin RL, Bray BD, Brooks NH, Hyatt AW, Wong CPC, Roquemore AL, Skinner CH, Solomon WM, Ratynskaia S, Fenstermacher ME, Groth M, Lasnier CJ, McLean AG, Stangeby PC. Dust measurements in tokamaks (invited). Rev Sci Instrum 2008; 79:10F303. [PMID: 19044616 DOI: 10.1063/1.2969422] [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] [Indexed: 05/27/2023]
Abstract
Dust production and accumulation present potential safety and operational issues for the ITER. Dust diagnostics can be divided into two groups: diagnostics of dust on surfaces and diagnostics of dust in plasma. Diagnostics from both groups are employed in contemporary tokamaks; new diagnostics suitable for ITER are also being developed and tested. Dust accumulation in ITER is likely to occur in hidden areas, e.g., between tiles and under divertor baffles. A novel electrostatic dust detector for monitoring dust in these regions has been developed and tested at PPPL. In the DIII-D tokamak dust diagnostics include Mie scattering from Nd:YAG lasers, visible imaging, and spectroscopy. Laser scattering is able to resolve particles between 0.16 and 1.6 microm in diameter; using these data the total dust content in the edge plasmas and trends in the dust production rates within this size range have been established. Individual dust particles are observed by visible imaging using fast framing cameras, detecting dust particles of a few microns in diameter and larger. Dust velocities and trajectories can be determined in two-dimension with a single camera or three-dimension using multiple cameras, but determination of particle size is challenging. In order to calibrate diagnostics and benchmark dust dynamics modeling, precharacterized carbon dust has been injected into the lower divertor of DIII-D. Injected dust is seen by cameras, and spectroscopic diagnostics observe an increase in carbon line (CI, CII, C(2) dimer) and thermal continuum emissions from the injected dust. The latter observation can be used in the design of novel dust survey diagnostics.
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Affiliation(s)
- D L Rudakov
- University of California, San Diego, California 92093, USA
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10
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Evans TE, Moyer RA, Thomas PR, Watkins JG, Osborne TH, Boedo JA, Doyle EJ, Fenstermacher ME, Finken KH, Groebner RJ, Groth M, Harris JH, La Haye RJ, Lasnier CJ, Masuzaki S, Ohyabu N, Pretty DG, Rhodes TL, Reimerdes H, Rudakov DL, Schaffer MJ, Wang G, Zeng L. Suppression of large edge-localized modes in high-confinement DIII-D plasmas with a stochastic magnetic boundary. Phys Rev Lett 2004; 92:235003. [PMID: 15245164 DOI: 10.1103/physrevlett.92.235003] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2003] [Indexed: 05/24/2023]
Abstract
A stochastic magnetic boundary, produced by an applied edge resonant magnetic perturbation, is used to suppress most large edge-localized modes (ELMs) in high confinement (H-mode) plasmas. The resulting H mode displays rapid, small oscillations with a bursty character modulated by a coherent 130 Hz envelope. The H mode transport barrier and core confinement are unaffected by the stochastic boundary, despite a threefold drop in the toroidal rotation. These results demonstrate that stochastic boundaries are compatible with H modes and may be attractive for ELM control in next-step fusion tokamaks.
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Affiliation(s)
- T E Evans
- General Atomics, San Diego, California, USA
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Colchin RJ, Schaffer MJ, Carreras BA, McKee GR, Maingi R, Carlstrom TN, Rudakov DL, Greenfield CM, Rhodes TL, Doyle EJ, Brooks NH, Austin ME. Slow L-H transitions in DIII-D plasmas. Phys Rev Lett 2002; 88:255002. [PMID: 12097092 DOI: 10.1103/physrevlett.88.255002] [Citation(s) in RCA: 4] [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: 09/24/2001] [Indexed: 05/23/2023]
Abstract
The transition from the low to the high mode of plasma confinement ( L-H transition) is studied in the DIII-D by an experimental technique which allows an arbitrarily slow transition. During an initial transition, periodic turbulent instability bursts are observed near the separatrix which inhibit the full transition. These bursts are damped by self-generated shear flows, and a predator-prey-type relationship is shown to give a good description of the data. As the neutral-beam power is raised, the oscillations change to type III edge localized modes. Another transition then leads to a quiet H mode.
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Affiliation(s)
- R J Colchin
- Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-8072, USA
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12
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Shats MG, Rudakov DL, Blackwell BD, Borg GG, Dewar RL, Hamberger SM, Howard J, Sharp LE. Improved Particle Confinement Mode in the H-1 Heliac Plasma. Phys Rev Lett 1996; 77:4190-4193. [PMID: 10062471 DOI: 10.1103/physrevlett.77.4190] [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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