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Kobayashi T, Fujisawa A, Nagashima Y, Moon C, Yamasaki K, Nishimura D, Inagaki S, Shimizu A, Tokuzawa T, Ido T. Identification of nonlinear effects of background asymmetry on solitary oscillations in a cylindrical plasma. Sci Rep 2024; 14:12175. [PMID: 38806603 PMCID: PMC11133312 DOI: 10.1038/s41598-024-62969-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2024] [Accepted: 05/23/2024] [Indexed: 05/30/2024] Open
Abstract
A symmetry-breaking in rotational spatial pattern of quasi-periodic solitary oscillations is revealed with tomography measurement of plasma emission, simultaneously with background asymmetry in stationary plasma structure. Although the oscillatory pattern deformation is a natural course in the presence of asymmetry, elaborate analyses identify existence unfeatured nonlinear effects of the background asymmetry, i.e., its nonlinear couplings with harmonic modes of rotational symmetry, to produce non-harmonic mode to break the symmetry and cause the oscillatory pattern to be chaotic. The findings suggest the unrecognized fundamental process for plasmas to be turbulent.
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Affiliation(s)
- Taiki Kobayashi
- Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, Kasuga, 816-8580, Japan.
| | - Akihide Fujisawa
- Research Institute for Applied Mechanics, Kyushu University, Kasuga, 816-8580, Japan
- Research Center for Plasma Turbulence, Kyushu University, Kasuga, 816-8580, Japan
- National Institute for Fusion Science, National Institute of Natural Sciences, Toki, 509-5292, Japan
| | - Yoshihiko Nagashima
- Research Institute for Applied Mechanics, Kyushu University, Kasuga, 816-8580, Japan
- Research Center for Plasma Turbulence, Kyushu University, Kasuga, 816-8580, Japan
| | - Chanho Moon
- Research Institute for Applied Mechanics, Kyushu University, Kasuga, 816-8580, Japan
- Research Center for Plasma Turbulence, Kyushu University, Kasuga, 816-8580, Japan
| | - Kotaro Yamasaki
- Graduate School of Advanced Science and Engineering, Hiroshima University, Higashihiroshima, 739-8527, Japan
| | - Daiki Nishimura
- Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, Kasuga, 816-8580, Japan
| | - Sigeru Inagaki
- Institute of Advanced Energy, Kyoto University, Uji, 611-0011, Japan
| | - Akihiro Shimizu
- Research Institute for Applied Mechanics, Kyushu University, Kasuga, 816-8580, Japan
- National Institute for Fusion Science, National Institute of Natural Sciences, Toki, 509-5292, Japan
| | - Tokihiko Tokuzawa
- Research Institute for Applied Mechanics, Kyushu University, Kasuga, 816-8580, Japan
- National Institute for Fusion Science, National Institute of Natural Sciences, Toki, 509-5292, Japan
| | - Takeshi Ido
- Research Institute for Applied Mechanics, Kyushu University, Kasuga, 816-8580, Japan
- Research Center for Plasma Turbulence, Kyushu University, Kasuga, 816-8580, Japan
- National Institute for Fusion Science, National Institute of Natural Sciences, Toki, 509-5292, Japan
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2
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Testing and analysis of steady-state helicon plasma source for the Material Plasma Exposure eXperiment (MPEX). FUSION ENGINEERING AND DESIGN 2020. [DOI: 10.1016/j.fusengdes.2020.112001] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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3
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Hong R, Li JC, Chakraborty Thakur S, Hajjar R, Diamond PH, Tynan GR. Tracing the Pathway from Drift-Wave Turbulence with Broken Symmetry to the Production of Sheared Axial Mean Flow. PHYSICAL REVIEW LETTERS 2018; 120:205001. [PMID: 29864290 DOI: 10.1103/physrevlett.120.205001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2017] [Revised: 02/20/2018] [Indexed: 06/08/2023]
Abstract
This study traces the emergence of sheared axial flow from collisional drift-wave turbulence with broken symmetry in a linear plasma device-the controlled shear decorrelation experiment. As the density profile steepens, the axial Reynolds stress develops and drives a radially sheared axial flow that is parallel to the magnetic field. Results show that the nondiffusive piece of the Reynolds stress is driven by the density gradient, results from spectral asymmetry of the turbulence, and, thus, is dynamical in origin. Taken together, these findings constitute the first simultaneous demonstration of the causal link between the density gradient, turbulence, and stress with broken spectral symmetry and the mean axial flow.
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Affiliation(s)
- R Hong
- Center for Energy Research, University of California San Diego, La Jolla, California 92093, USA
| | - J C Li
- Center for Astrophysics and Space Sciences, University of California San Diego, La Jolla, California 92093, USA
| | - S Chakraborty Thakur
- Center for Energy Research, University of California San Diego, La Jolla, California 92093, USA
| | - R Hajjar
- Center for Energy Research, University of California San Diego, La Jolla, California 92093, USA
| | - P H Diamond
- Center for Astrophysics and Space Sciences, University of California San Diego, La Jolla, California 92093, USA
- Center for Fusion Science, Southwestern Institute of Physics, Chengdu, Sichuan 610041, China
| | - G R Tynan
- Center for Energy Research, University of California San Diego, La Jolla, California 92093, USA
- Center for Fusion Science, Southwestern Institute of Physics, Chengdu, Sichuan 610041, China
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4
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Eddy, drift wave and zonal flow dynamics in a linear magnetized plasma. Sci Rep 2016; 6:33371. [PMID: 27628894 PMCID: PMC5024127 DOI: 10.1038/srep33371] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Accepted: 08/25/2016] [Indexed: 11/12/2022] Open
Abstract
Turbulence and its structure formation are universal in neutral fluids and in plasmas. Turbulence annihilates global structures but can organize flows and eddies. The mutual-interactions between flow and the eddy give basic insights into the understanding of non-equilibrium and nonlinear interaction by turbulence. In fusion plasma, clarifying structure formation by Drift-wave turbulence, driven by density gradients in magnetized plasma, is an important issue. Here, a new mutual-interaction among eddy, drift wave and flow in magnetized plasma is discovered. A two-dimensional solitary eddy, which is a perturbation with circumnavigating motion localized radially and azimuthally, is transiently organized in a drift wave – zonal flow (azimuthally symmetric band-like shear flows) system. The excitation of the eddy is synchronized with zonal perturbation. The organization of the eddy has substantial impact on the acceleration of zonal flow.
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Takahashi K, Chiba A, Komuro A, Ando A. Axial momentum lost to a lateral wall of a helicon plasma source. PHYSICAL REVIEW LETTERS 2015; 114:195001. [PMID: 26024174 DOI: 10.1103/physrevlett.114.195001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2015] [Indexed: 06/04/2023]
Abstract
Momentum exerted to a lateral wall of a helicon plasma source is individually measured for argon, krypton, and xenon gases. A significant loss of the axial plasma momentum to the lateral wall, which has been assumed to be negligible, is experimentally identified when an axially asymmetric density profile is formed in the source. This indicates that the radially lost ions deliver not only the radial momentum but also the axial momentum to the lateral wall. The formation of the axial asymmetry causing the momentum loss is interpreted with competition between the magnetic field and neutral depletion effects.
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Affiliation(s)
- Kazunori Takahashi
- Department of Electrical Engineering, Tohoku University, Sendai 980-8579, Japan
| | - Aiki Chiba
- Department of Electrical Engineering, Tohoku University, Sendai 980-8579, Japan
| | - Atsushi Komuro
- Department of Electrical Engineering, Tohoku University, Sendai 980-8579, Japan
| | - Akira Ando
- Department of Electrical Engineering, Tohoku University, Sendai 980-8579, Japan
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Thakur SC, McCarren D, Lee T, Fedorczak N, Manz P, Scime EE, Tynan GR, Xu M, Yu J. Comparison of azimuthal ion velocity profiles using Mach probes, time delay estimation, and laser induced fluorescence in a linear plasma device. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2012; 83:10D708. [PMID: 23126882 DOI: 10.1063/1.4731005] [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
We compare measurements of radially sheared azimuthal plasma flow based on time delay estimation (TDE) between two spatially separated Langmuir probes, Mach probes and laser induced fluorescence (LIF). TDE measurements cannot distinguish between ion fluid velocities and phase velocities. TDE and Mach probes are perturbative, so we compare the results against LIF, a non-perturbative, spatially resolved diagnostic technique that provides direct measurements of the ion velocity distribution functions. The bulk ion flow is determined from the Doppler shift of the Argon absorption line at 668.6139 nm. We compare results from all the three diagnostics, at various magnetic fields, which acts as a control knob for development of drift wave turbulence. We find that while Mach probes and LIF give similar profiles, TDE measurements typically overestimate the velocities and are also sensitive to the drift wave modes being investigated.
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Affiliation(s)
- S Chakraborty Thakur
- Center for Momentum Transport and Flow Organization, University of California at San Diego, 92093, USA.
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7
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Schaffner DA, Carter TA, Rossi GD, Guice DS, Maggs JE, Vincena S, Friedman B. Modification of turbulent transport with continuous variation of flow shear in the large plasma device. PHYSICAL REVIEW LETTERS 2012; 109:135002. [PMID: 23030095 DOI: 10.1103/physrevlett.109.135002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/12/2012] [Indexed: 06/01/2023]
Abstract
Continuous control over azimuthal flow and shear in the edge of the Large Plasma Device (LAPD) has been achieved using a biasable limiter which has allowed a careful study of the effect of flow shear on pressure-gradient-driven turbulence and transport in the LAPD. The LAPD rotates spontaneously in the ion diamagnetic direction; positive limiter bias first reduces, then minimizes (producing a near-zero shear state), and finally reverses the flow into the electron diamagnetic direction. Degradation of particle confinement is observed in the minimum shearing state and a reduction in the turbulent particle flux is observed with increasing shearing in both flow directions. Near-complete suppression of the turbulent particle flux is observed for shearing rates comparable to the turbulent autocorrelation rate measured in the minimum shear state. Turbulent flux suppression is dominated by amplitude reduction in low-frequency (<10 kHz) density fluctuations. An increase in fluctuations for the highest shearing states is observed with the emergence of a coherent mode which does not lead to net particle transport. The variations of density fluctuations are fit well with power laws and compare favorably to simple models of shear suppression of transport.
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Affiliation(s)
- D A Schaffner
- Department of Physics and Astronomy, University of California, Los Angeles, California 90095, USA
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Xu M, Tynan GR, Diamond PH, Holland C, Yu JH, Yan Z. Generation of a sheared plasma rotation by emission, propagation, and absorption of drift wave packets. PHYSICAL REVIEW LETTERS 2011; 107:055003. [PMID: 21867076 DOI: 10.1103/physrevlett.107.055003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2010] [Indexed: 05/31/2023]
Abstract
Collisional electron drift wave turbulence generates drift wave packet structures with density and vorticity fluctuations in the central plasma pressure gradient region of a linear plasma device. Tracking these packets reveals that they follow an outward directed spiral-shaped trajectory in the (r,θ) plane, are azimuthally stretched, and develop anisotropy as they approach an axisymmetric, radially sheared azimuthal flow located at the plasma boundary. Nonlinear energy transfer measurements and time-delay analysis confirm that structure absorption amplifies the sheared flow. Similar mechanisms likely operate at the edge of confined toroidal plasmas and should lead to the amplification of sheared flows at the boundary of these devices as well.
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Affiliation(s)
- M Xu
- Center for Momentum Transport and Flow Organization, University of California at San Diego, San Diego, California, USA
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Yamada T, Itoh SI, Inagaki S, Nagashima Y, Kasuya N, Kamataki K, Arakawa H, Kobayashi T, Yagi M, Fujisawa A, Itoh K. Observation of quasi-two-dimensional nonlinear interactions in a drift-wave streamer. PHYSICAL REVIEW LETTERS 2010; 105:225002. [PMID: 21231392 DOI: 10.1103/physrevlett.105.225002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2010] [Indexed: 05/30/2023]
Abstract
A streamer, which is a bunching of drift-wave fluctuations, and its mediator, which generates the streamer by coupling with other fluctuations, have been observed in a cylindrical magnetized plasma. Their radial structures were investigated in detail by using the biphase analysis. Their quasi-two-dimensional structures were revealed to be equivalent with a pair of fast and slow modes predicted by a nonlinear Schrödinger equation based on the Hasegawa-Mima model.
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Affiliation(s)
- T Yamada
- Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Chiba 277-8561, Japan.
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Yan Z, Xu M, Diamond PH, Holland C, Müller SH, Tynan GR, Yu JH. Intrinsic rotation from a residual stress at the boundary of a cylindrical laboratory plasma. PHYSICAL REVIEW LETTERS 2010; 104:065002. [PMID: 20366825 DOI: 10.1103/physrevlett.104.065002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2009] [Indexed: 05/29/2023]
Abstract
An azimuthally symmetric radially sheared azimuthal flow is driven by a nondiffusive, or residual, turbulent stress localized to a narrow annular region at the boundary of a cylindrical magnetized helicon plasma device. A no-slip condition, imposed by ion-neutral flow damping outside the annular region, combined with a diffusive stress arising from turbulent and collisional viscous damping in the central plasma region, leads to net plasma rotation in the absence of momentum input.
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Affiliation(s)
- Z Yan
- Department of Mechanical and Aerospace Engineering & Center for Energy Research, University of California San Diego, San Diego, California, USA
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11
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Yamada T, Nagashima Y, Inagaki S, Kawai Y, Yagi M, Itoh SI, Maruta T, Shinohara S, Terasaka K, Kawaguchi M, Fukao M, Fujisawa A, Itoh K. Fine positioning of a poloidal probe array. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2007; 78:123501. [PMID: 18163726 DOI: 10.1063/1.2818796] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Multipoint detection is an essential requirement for investigating plasma turbulence which is a highly nonlinear phenomenon in space and time. We have fabricated an array of 64-channel poloidal probes surrounding the linear cylindrical plasma named LMD-U in order to study turbulence properties, particularly the nonlinear mode couplings, in the domain of poloidal wave number and frequency. However, misalignments of probe tips produce spurious modes, which do not exist in the real plasma, to distort the precise wave number measurements. The paper presents the description of the 64-channel poloidal probe array with means to adjust the probe positions, with discussion on the effects of the misalignments on the wave number measurements.
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Affiliation(s)
- T Yamada
- Research Institute for Applied Mechanics, Kyushu University, Kasuga 816-8580, Japan.
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