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Logan NC, Hu Q, Paz-Soldan C, Nazikian R, Rhodes T, Wilks T, Munaretto S, Bortolon A, Laggner F, Scotti F, Hong R, Wang H. Improved Particle Confinement with Resonant Magnetic Perturbations in DIII-D Tokamak H-Mode Plasmas. PHYSICAL REVIEW LETTERS 2022; 129:205001. [PMID: 36461991 DOI: 10.1103/physrevlett.129.205001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Revised: 07/22/2022] [Accepted: 10/12/2022] [Indexed: 06/17/2023]
Abstract
Experiments on the DIII-D tokamak have identified a novel regime in which applied resonant magnetic perturbations (RMPs) increase the particle confinement and overall performance. This Letter details a robust range of counter-current rotation over which RMPs cause this density pump-in effect for high confinement (H mode) plasmas. The pump in is shown to be caused by a reduction of the turbulent transport and to be correlated with a change in the sign of the induced neoclassical transport. This novel reversal of the RMP induced transport has the potential to significantly improve reactor relevant, three-dimensional magnetic confinement scenarios.
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Affiliation(s)
- N C Logan
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - Q Hu
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08540, USA
| | - C Paz-Soldan
- General Atomics, San Diego, California 92186, USA
| | - R Nazikian
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08540, USA
| | - T Rhodes
- University of California, Los Angeles, Los Angeles, California 90095, USA
| | - T Wilks
- Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - S Munaretto
- General Atomics, San Diego, California 92186, USA
| | - A Bortolon
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08540, USA
| | - F Laggner
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08540, USA
| | - F Scotti
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - R Hong
- University of California, Los Angeles, Los Angeles, California 90095, USA
| | - H Wang
- General Atomics, San Diego, California 92186, USA
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Sohrabi A, Jazayeri SM. The Effect of “Locally Modifying Safety Factor Barrier” on Confinement Time in Tokamak with Magnetic Divertor. JOURNAL OF FUSION ENERGY 2015. [DOI: 10.1007/s10894-014-9777-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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3
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Stenson EV, Bellan PM. Magnetically driven flows in arched plasma structures. PHYSICAL REVIEW LETTERS 2012; 109:075001. [PMID: 23006376 DOI: 10.1103/physrevlett.109.075001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2011] [Indexed: 06/01/2023]
Abstract
Laboratory experiments demonstrate high-speed plasma flows from both footpoints of arched magnetic flux tubes, resulting in bulk plasma transport into the flux tube and persistent axial collimation even as the flux tube lengthens and kinks. The measured flows are in agreement with the predictions of hoop force and collimation models involving fundamental MHD forces. These forces are expected to drive plasma acceleration in other open flux configurations with arched geometries, such as those found on the solar surface.
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Affiliation(s)
- E V Stenson
- California Institute of Technology, Pasadena, 91125, USA.
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Rack M, Spatschek KH, Wingen A. Diffusion in a collisional standard map. CHAOS (WOODBURY, N.Y.) 2012; 22:023114. [PMID: 22757521 DOI: 10.1063/1.4704386] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Test particle evaluation of the diffusion coefficient in the presence of magnetic field fluctuations and binary collisions is presented. Chaotic magnetic field lines originate from resonant magnetic perturbations (RMPs). To lowest order, charged particles follow magnetic field lines. Drifts and interaction (collisions) with other particles decorrelate particles from the magnetic field lines. We model the binary collision process by a constant collision frequency. The magnetic field configuration including perturbations on the integrable Hamiltonian part is such that the single particle motion can be followed by a collisional version of a Chirikov-Taylor (standard) map. Frequent collisions are allowed for. Scaling of the diffusion beyond the quasilinear and subdiffusive behaviour is investigated in dependence on the strength of the magnetic perturbations and the collision frequency. The appearance of the so called Rechester-Rosenbluth regime is verified. It is further shown that the so called Kadomtsev-Pogutse diffusion coefficient is the strong collisional limit of the Rechester-Rosenbluth formula. The theoretical estimates are supplemented by numerical simulations.
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Affiliation(s)
- M Rack
- Institut für Theoretische Physik, Heinrich-Heine-Universität Düsseldorf, D-40225 Düsseldorf, Germany
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Ding WX, Brower DL, Yates TY. Measurement of magnetic fluctuation-induced particle flux (invited). THE REVIEW OF SCIENTIFIC INSTRUMENTS 2008; 79:10E701. [PMID: 19044519 DOI: 10.1063/1.2953437] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Magnetic field fluctuation-induced particle transport has been directly measured in the high-temperature core of the MST reversed field pinch plasma. Measurement of radial particle transport is achieved by combining various interferometry techniques, including Faraday rotation, conventional interferometry, and differential interferometry. It is observed that electron convective particle flux and its divergence exhibit a significant increase during a sawtooth crash. In this paper, we describe the basic techniques employed to determine the particle flux.
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Affiliation(s)
- W X Ding
- Department of Physics and Astronomy, University of California-Los Angeles, Los Angeles, California 90095, USA
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Ding WX, Brower DL, Craig D, Deng BH, Prager SC, Sarff JS, Svidzinski V. Nonambipolar magnetic-fluctuation-induced particle transport and plasma flow in the MST reversed-field pinch. PHYSICAL REVIEW LETTERS 2007; 99:055004. [PMID: 17930765 DOI: 10.1103/physrevlett.99.055004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2007] [Indexed: 05/25/2023]
Abstract
First direct measurements of nonambipolar magnetic fluctuation-induced charge transport in the interior of a high-temperature plasma are reported. Global resistive tearing modes drive the charge transport which is measured in the vicinity of the resonant surface for the dominant core resonant mode. Finite charge transport has two important consequences. First, it generates a potential well along with locally strong electric field and electric field shear at the resonant surface. Second, this electric field induces a spontaneous E x B driven zonal flow.
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Affiliation(s)
- W X Ding
- Department of Physics and Astronomy, University of California at Los Angeles, Los Angeles, California 90095, USA
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