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Unterberg B, Samm U, Tokar’ MZ, Messiaen AM, Ongena J, Jaspers R. The Radiative Improved Mode in TEXTOR: Power Exhaust and Improved Confinement at High Density. FUSION SCIENCE AND TECHNOLOGY 2017. [DOI: 10.13182/fst05-a699] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- B. Unterberg
- Institut für Plasmaphysik, Forschungszentrum Jülich GmbH EURATOM Association, Trilateral Euregio Cluster, D-52425 Jülich, Germany
| | - U. Samm
- Institut für Plasmaphysik, Forschungszentrum Jülich GmbH EURATOM Association, Trilateral Euregio Cluster, D-52425 Jülich, Germany
| | - M. Z. Tokar’
- Institut für Plasmaphysik, Forschungszentrum Jülich GmbH EURATOM Association, Trilateral Euregio Cluster, D-52425 Jülich, Germany
| | - A. M. Messiaen
- Laboratory for Plasma Physics, Ecole Royale Militaire - Koninklijke Militaire School, Association EURATOM-Belgian State, Trilateral Euregio Cluster B-1000 Brussels, Belgium
| | - J. Ongena
- Laboratory for Plasma Physics, Ecole Royale Militaire - Koninklijke Militaire School, Association EURATOM-Belgian State, Trilateral Euregio Cluster B-1000 Brussels, Belgium
| | - R. Jaspers
- Institute for Plasma Physics Rijnhuizen, Association EURATOM-FOM Trilateral Euregio Cluster, P.O. Box 1207, NL-3430 BE Nieuwegein, The Netherlands
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Burrell KH. Role of E × B Shear and Magnetic Shear in the Formation of Transport Barriers in DIII-D. FUSION SCIENCE AND TECHNOLOGY 2017. [DOI: 10.13182/fst05-a1057] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- K. H. Burrell
- General Atomics, P.O. Box 85608, San Diego, California 92186-5608
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Thomas DM, McKee GR, Burrell KH, Levinton F, Foley EL, Fisher RK. Chapter 6: Active Spectroscopy. FUSION SCIENCE AND TECHNOLOGY 2017. [DOI: 10.13182/fst08-a1678] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- D. M. Thomas
- General Atomics, P.O. Box 85608, San Diego, California 92186-5608
| | - G. R. McKee
- University of Wisconsin-Madison, Madison, Wisconsin
| | - K. H. Burrell
- General Atomics, P.O. Box 85608, San Diego, California 92186-5608
| | | | | | - R. K. Fisher
- General Atomics, P.O. Box 85608, San Diego, California 92186-5608
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Pokol G, Zoletnik S, Dunai D, Marchuk O, Baross T, Erdei G, Grunda G, Kiss I, Kovacsik A, v.Hellermann M, Lischtschenko O, Biel W, Jaspers R, Durkut M. Fluctuation BES measurements with the ITER core CXRS prototype spectrometer. FUSION ENGINEERING AND DESIGN 2013. [DOI: 10.1016/j.fusengdes.2013.02.171] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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5
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Liu Y, Shi ZB, Dong YB, Sun HJ, Sun AP, Li YG, Xia ZW, Li W, Ding XT, Xiao WW, Zhou Y, Zhou J, Rao J, Liu ZT, Yang QW, Duan XR. Observation of turbulence suppression after electron-cyclotron-resonance-heating switch-off on the HL-2A tokamak. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2011; 84:016403. [PMID: 21867318 DOI: 10.1103/physreve.84.016403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2010] [Revised: 04/15/2011] [Indexed: 05/31/2023]
Abstract
The formation of a transient internal transport barrier (ITB) is observed after the electron-cyclotron-resonance-heating (ECRH) switch-off in the HL-2A plasmas, characterized by transient increase of central electron temperature. The newly developed correlation reflectometer provided direct measurements showing reduction of turbulence in the region of steepened gradients for the period of ITB formation triggered by the ECRH switch-off. Furthermore, the reduction of core turbulence is correlated in time with the appearance of a low-frequency mode with a spectrally broad poloidal structure that peaks near zero frequency in the core region. These structures have low poloidal mode number, high poloidal correlation, and short radial correlation and are strongly coupled with high-frequency ambient turbulence. Observation indicates that these structures play important roles in the reduction of the core turbulence and in improvements of the core transport after the off-axis ECRH is turned off.
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Affiliation(s)
- Y Liu
- Southwestern Institute of Physics, Chengdu, China.
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Nazikian R, Fu GY, Austin ME, Berk HL, Budny RV, Gorelenkov NN, Heidbrink WW, Holcomb CT, Kramer GJ, McKee GR, Makowski MA, Solomon WM, Shafer M, Strait EJ, Zeeland MAV. Intense geodesic acousticlike modes driven by suprathermal ions in a tokamak plasma. PHYSICAL REVIEW LETTERS 2008; 101:185001. [PMID: 18999835 DOI: 10.1103/physrevlett.101.185001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2008] [Indexed: 05/27/2023]
Abstract
Intense axisymmetric oscillations driven by suprathermal ions injected in the direction counter to the toroidal plasma current are observed in the DIII-D tokamak. The modes appear at nearly half the ideal geodesic acoustic mode frequency, in plasmas with comparable electron and ion temperatures and elevated magnetic safety factor (q_{min}>or=2). Strong bursting and frequency chirping are observed, concomitant with large (10%-15%) drops in the neutron emission. Large electron density fluctuations (n[over ]_{e}/n_{e} approximately 1.5%) are observed with no detectable electron temperature fluctuations, confirming a dominant compressional contribution to the pressure perturbation as predicted by kinetic theory. The observed mode frequency is consistent with a recent theoretical prediction for the energetic-particle-driven geodesic acoustic mode.
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Affiliation(s)
- R Nazikian
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA
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7
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Nazikian R, Berk HL, Budny RV, Burrell KH, Doyle EJ, Fonck RJ, Gorelenkov NN, Holcomb C, Kramer GJ, Jayakumar RJ, La Haye RJ, McKee GR, Makowski MA, Peebles WA, Rhodes TL, Solomon WM, Strait EJ, Vanzeeland MA, Zeng L. Multitude of core-localized shear Alfvén waves in a high-temperature fusion plasma. PHYSICAL REVIEW LETTERS 2006; 96:105006. [PMID: 16605746 DOI: 10.1103/physrevlett.96.105006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2005] [Indexed: 05/08/2023]
Abstract
Evidence is presented for a multitude of discrete frequency Alfvén waves in the core of magnetically confined high-temperature fusion plasmas. Multiple diagnostic instruments confirm wave excitation over a wide spatial range from the device size at the longest wavelengths down to the thermal ion Larmor radius. At the shortest scales, the poloidal wavelengths are comparable to the scale length of electrostatic drift wave turbulence. Theoretical analysis confirms a dominant interaction of the modes with particles in the thermal ion distribution traveling well below the Alfvén velocity.
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Affiliation(s)
- R Nazikian
- Princeton Plasma Physics Laboratory, P.O. Box 451, Princeton, New Jersey 08543, USA.
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