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Yoon YD, Laishram M, Moore TE, Yun GS. Non-equilibrium formation and relaxation of magnetic flux ropes at kinetic scales. COMMUNICATIONS PHYSICS 2024; 7:297. [PMID: 39239357 PMCID: PMC11371647 DOI: 10.1038/s42005-024-01784-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/25/2024] [Accepted: 08/19/2024] [Indexed: 09/07/2024]
Abstract
Magnetic flux ropes are pivotal structures and building blocks in astrophysical and laboratory plasmas, and various equilibrium models have thus been studied in the past. However, flux ropes in general form at non-equilibrium, and their pathway from formation to relaxation is a crucial process that determines their eventual properties. Here we show that any localized current parallel to a background magnetic field will evolve into a flux rope via non-equilibrium processes. The detailed kinetic dynamics are exhaustively explained through single-particle and Vlasov analyses and verified through particle-in-cell simulations. This process is consistent with many proposed mechanisms of flux rope generation such as magnetic reconnection. A spacecraft observation of an example flux rope is also presented; by invoking the non-equilibrium process, its structure and properties can be explicated down to all six components of the temperature tensor.
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Affiliation(s)
- Young Dae Yoon
- Asia Pacific Center for Theoretical Physics, Pohang, Gyeongbuk 37673 South Korea
- Department of Physics, Pohang University of Science and Technology, Pohang, Gyeongbuk 37673 South Korea
| | | | | | - Gunsu S Yun
- Department of Physics, Pohang University of Science and Technology, Pohang, Gyeongbuk 37673 South Korea
- Department of Advanced Nuclear Engineering, Pohang University of Science and Technology, Pohang, Gyeongbuk 37673 South Korea
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2
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Zhou Y, Pree S, Bellan PM. Imaging suprathermal x-rays from a laboratory plasma jet using PIN-diode-based and scintillator-based 1D pinhole/coded aperture cameras. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2023; 94:013504. [PMID: 36725608 DOI: 10.1063/5.0122760] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Accepted: 12/22/2022] [Indexed: 06/18/2023]
Abstract
A PIN-diode-based 1D x-ray camera and a scintillator-based 1D x-ray camera, both with a microsecond to submicrosecond time resolution, have been developed to perform time-resolved imaging of transient, low-intensity, suprathermal x-rays associated with magnetohydrodynamic instabilities disrupting a plasma jet. These cameras have a high detection efficiency over a broad x-ray band, a wide field of view, and the capability to produce >50 time-resolved frames with a ≤1 μs time resolution. The x-ray images are formed by a pinhole or by a coded aperture placed outside a vacuum chamber in which the plasma jet is launched. The 1D imaging shows that the location of the x-ray source is either a few centimeters away from an inner disk electrode or near a spatially translatable metal frame that is 30-40 cm away from the electrode. Compared to a pinhole, a coded aperture increases the signal collection efficiency but also introduces unwanted artifacts.
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Affiliation(s)
- Yi Zhou
- Department of Applied Physics and Materials Science, California Institute of Technology, Pasadena, California 91125, USA
| | - Seth Pree
- Department of Applied Physics and Materials Science, California Institute of Technology, Pasadena, California 91125, USA
| | - Paul M Bellan
- Department of Applied Physics and Materials Science, California Institute of Technology, Pasadena, California 91125, USA
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3
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Li E, Zou XL, Xu LQ, Chu YQ, Feng X, Lian H, Liu HQ, Liu AD, Han MK, Dong JQ, Wang HH, Liu JW, Zang Q, Wang SX, Zhou TF, Huang YH, Hu LQ, Zhou C, Qu HX, Chen Y, Lin SY, Zhang B, Qian JP, Hu JS, Xu GS, Chen JL, Lu K, Liu FK, Song YT, Li JG, Gong XZ. Experimental Evidence of Intrinsic Current Generation by Turbulence in Stationary Tokamak Plasmas. PHYSICAL REVIEW LETTERS 2022; 128:085003. [PMID: 35275672 DOI: 10.1103/physrevlett.128.085003] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 09/16/2021] [Accepted: 02/01/2022] [Indexed: 06/14/2023]
Abstract
High-β_{θe} (a ratio of the electron thermal pressure to the poloidal magnetic pressure) steady-state long-pulse plasmas with steep central electron temperature gradient are achieved in the Experimental Advanced Superconducting Tokamak. An intrinsic current is observed to be modulated by turbulence driven by the electron temperature gradient. This turbulent current is generated in the countercurrent direction and can reach a maximum ratio of 25% of the bootstrap current. Gyrokinetic simulations and experimental observations indicate that the turbulence is the electron temperature gradient mode (ETG). The dominant mechanism for the turbulent current generation is due to the divergence of ETG-driven residual flux of current. Good agreement has been found between experiments and theory for the critical value of the electron temperature gradient triggering ETG and for the level of the turbulent current. The maximum values of turbulent current and electron temperature gradient lead to the destabilization of an m/n=1/1 kink mode, which by counteraction reduces the turbulence level (m and n are the poloidal and toroidal mode number, respectively). These observations suggest that the self-regulation system including turbulence, turbulent current, and kink mode is a contributing mechanism for sustaining the steady-state long-pulse high-β_{θe} regime.
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Affiliation(s)
- Erzhong Li
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, People's Republic of China
| | - X L Zou
- CEA, IRFM, F-13108 Saint-Paul-lez-Durance, France
| | - L Q Xu
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, People's Republic of China
| | - Y Q Chu
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, People's Republic of China
- University of Science and Technology of China, Hefei 230022, People's Republic of China
| | - X Feng
- University of Science and Technology of China, Hefei 230022, People's Republic of China
| | - H Lian
- University of California Los Angeles, Los Angeles, California 90095, USA
| | - H Q Liu
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, People's Republic of China
| | - A D Liu
- University of Science and Technology of China, Hefei 230022, People's Republic of China
| | - M K Han
- Southwestern Institute of Physics, P.O. Box 432, Chengdu 610041, People's Republic of China
| | - J Q Dong
- Southwestern Institute of Physics, P.O. Box 432, Chengdu 610041, People's Republic of China
| | - H H Wang
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, People's Republic of China
| | - J W Liu
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, People's Republic of China
- University of Science and Technology of China, Hefei 230022, People's Republic of China
| | - Q Zang
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, People's Republic of China
| | - S X Wang
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, People's Republic of China
| | - T F Zhou
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, People's Republic of China
| | - Y H Huang
- Advanced Energy Research Center, Shenzhen University, Shenzhen 518060, People's Republic of China
| | - L Q Hu
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, People's Republic of China
| | - C Zhou
- University of Science and Technology of China, Hefei 230022, People's Republic of China
| | - H X Qu
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, People's Republic of China
- University of Science and Technology of China, Hefei 230022, People's Republic of China
| | - Y Chen
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, People's Republic of China
- University of Science and Technology of China, Hefei 230022, People's Republic of China
| | - S Y Lin
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, People's Republic of China
| | - B Zhang
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, People's Republic of China
| | - J P Qian
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, People's Republic of China
| | - J S Hu
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, People's Republic of China
| | - G S Xu
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, People's Republic of China
| | - J L Chen
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, People's Republic of China
| | - K Lu
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, People's Republic of China
| | - F K Liu
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, People's Republic of China
| | - Y T Song
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, People's Republic of China
| | - J G Li
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, People's Republic of China
| | - X Z Gong
- Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031, People's Republic of China
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Lavine ES, You S. Helical Shear-Flow Stabilization of an Astrophysically Relevant Laboratory Plasma Jet. PHYSICAL REVIEW LETTERS 2019; 123:145002. [PMID: 31702193 DOI: 10.1103/physrevlett.123.145002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Revised: 04/03/2019] [Indexed: 06/10/2023]
Abstract
Astrophysical jets are collimated, high-speed outflows observed to be natural features of celestial objects that spin and accrete matter. From protoplanetary nebula and young stellar objects to active galactic nuclei, common features suggest that universal mechanisms may lead to the remarkable straightness observed in many jets. Here we report observations from a new astrophysically relevant laboratory plasma jet experiment demonstrating the formation of long-lived, collimated, high aspect-ratio jets. The magnetized jets have strong helical shear flows and remain stable to instabilities over many growth times. These observations corroborate theoretical predictions that strong helical shear flows can stabilize current-driven instabilities in magnetically confined plasmas, solar prominences, and magnetically driven astrophysical jets in nature.
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Affiliation(s)
- Eric Sander Lavine
- University of Washington, William E. Boeing department of Aeronautics and Astronautics, Seattle, Washington 98105, USA
| | - Setthivoine You
- University of Washington, William E. Boeing department of Aeronautics and Astronautics, Seattle, Washington 98105, USA
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Abstract
Instabilities play a prominent role in determining the inherent structure and properties of magnetized plasma jets spanning both laboratory and astrophysical settings. The manner in which prominent unstable modes dynamically evolve remains key to understanding plasma behavior and control. In astrophysical phenomena, self-similar jets are observed to propagate over vast distances while avoiding breakup caused by unstable mode growth. However, the production of stable dense plasma jets in the laboratory has been limited by the onset of unstable modes that restrict jet lifetime, collimation, and scalability. In this work, we visualize the formation of stable laboratory-generated, dense, super-magnetosonic plasma jets in real time, and we identify an underlying mechanism that contributes to this behavior. The current-driven plasma jets generated in our experiments form a flowing Z-pinch, which is generally unstable to the m = 1 kink instability. Our results indicate that a stable dense plasma jet can be maintained for timescales over which a steady pinch current can be sustained, even at levels which would otherwise lead to rapid unstable mode growth and resultant pinch disassembly.
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von der Linden J, Sears J, Intrator T, You S. Measurements of the Canonical Helicity of a Gyrating Kink. PHYSICAL REVIEW LETTERS 2018; 121:035001. [PMID: 30085816 DOI: 10.1103/physrevlett.121.035001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Indexed: 06/08/2023]
Abstract
Conversions between magnetic and kinetic energy occur over a range of plasma scales in astrophysical and solar dynamos and reconnection in the solar corona and the laboratory. Canonical flux tubes reconcile all plasma regimes with concepts of twists, writhes, and linkages. We present measurements of canonical flux tubes, their helicity, and their helicity transport in a gyrating plasma kink. The helicity gauge is removed with general techniques valid even if only a limited section of the plasma is measured. Temporal asymmetries in the helicities confirm irreducible 3D fields in the kink.
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Affiliation(s)
| | - Jason Sears
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - Thomas Intrator
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - Setthivoine You
- Graduate School of Frontier Sciences, University of Tokyo, Tokyo 113-0032, Japan
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7
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The Mochi LabJet Experiment for Measurements of Canonical Helicity Injection in a Laboratory Astrophysical Jet. ACTA ACUST UNITED AC 2018. [DOI: 10.3847/1538-4365/aaba6f] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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8
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Matsumoto T, Roche T, Allfrey I, Sekiguchi J, Asai T, Gota H, Cordero M, Garate E, Kinley J, Valentine T, Waggoner W, Binderbauer M, Tajima T. Characterization of compact-toroid injection during formation, translation, and field penetration. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2016; 87:11D406. [PMID: 27910693 DOI: 10.1063/1.4959571] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We have developed a compact toroid (CT) injector system for particle refueling of the advanced beam-driven C-2U field-reversed configuration (FRC) plasma. The CT injector is a magnetized coaxial plasma gun (MCPG), and the produced CT must cross the perpendicular magnetic field surrounding the FRC for the refueling of C-2U. To simulate this environment, an experimental test stand has been constructed. A transverse magnetic field of ∼1 kG is established, which is comparable to the C-2U axial magnetic field in the confinement section, and CTs are fired across it. On the test stand we have been characterizing and studying CT formation, ejection/translation from the MCPG, and penetration into transverse magnetic fields.
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Affiliation(s)
- T Matsumoto
- Nihon University, Chiyoda-ku, Tokyo 101-8308, Japan
| | - T Roche
- Tri Alpha Energy, Inc., P.O. Box 7010, Rancho Santa Margarita, California 92688, USA
| | - I Allfrey
- Tri Alpha Energy, Inc., P.O. Box 7010, Rancho Santa Margarita, California 92688, USA
| | - J Sekiguchi
- Nihon University, Chiyoda-ku, Tokyo 101-8308, Japan
| | - T Asai
- Nihon University, Chiyoda-ku, Tokyo 101-8308, Japan
| | - H Gota
- Tri Alpha Energy, Inc., P.O. Box 7010, Rancho Santa Margarita, California 92688, USA
| | - M Cordero
- Tri Alpha Energy, Inc., P.O. Box 7010, Rancho Santa Margarita, California 92688, USA
| | - E Garate
- Tri Alpha Energy, Inc., P.O. Box 7010, Rancho Santa Margarita, California 92688, USA
| | - J Kinley
- Tri Alpha Energy, Inc., P.O. Box 7010, Rancho Santa Margarita, California 92688, USA
| | - T Valentine
- Tri Alpha Energy, Inc., P.O. Box 7010, Rancho Santa Margarita, California 92688, USA
| | - W Waggoner
- Tri Alpha Energy, Inc., P.O. Box 7010, Rancho Santa Margarita, California 92688, USA
| | - M Binderbauer
- Tri Alpha Energy, Inc., P.O. Box 7010, Rancho Santa Margarita, California 92688, USA
| | - T Tajima
- Tri Alpha Energy, Inc., P.O. Box 7010, Rancho Santa Margarita, California 92688, USA
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9
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Chaplin VH, Bellan PM. Battery-powered pulsed high density inductively coupled plasma source for pre-ionization in laboratory astrophysics experiments. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2015; 86:073506. [PMID: 26233382 DOI: 10.1063/1.4926544] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2015] [Accepted: 06/29/2015] [Indexed: 06/04/2023]
Abstract
An electrically floating radiofrequency (RF) pre-ionization plasma source has been developed to enable neutral gas breakdown at lower pressures and to access new experimental regimes in the Caltech laboratory astrophysics experiments. The source uses a customized 13.56 MHz class D RF power amplifier that is powered by AA batteries, allowing it to safely float at 3-6 kV with the electrodes of the high voltage pulsed power experiments. The amplifier, which is capable of 3 kW output power in pulsed (<1 ms) operation, couples electrical energy to the plasma through an antenna external to the 1.1 cm radius discharge tube. By comparing the predictions of a global equilibrium discharge model with the measured scalings of plasma density with RF power input and axial magnetic field strength, we demonstrate that inductive coupling (rather than capacitive coupling or wave damping) is the dominant energy transfer mechanism. Peak ion densities exceeding 5 × 10(19) m(-3) in argon gas at 30 mTorr have been achieved with and without a background field. Installation of the pre-ionization source on a magnetohydrodynamically driven jet experiment reduced the breakdown time and jitter and allowed for the creation of hotter, faster argon plasma jets than was previously possible.
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Affiliation(s)
- Vernon H Chaplin
- California Institute of Technology, Pasadena, California 91125, USA
| | - Paul M Bellan
- California Institute of Technology, Pasadena, California 91125, USA
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10
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Guo HY, Binderbauer MW, Tajima T, Milroy RD, Steinhauer LC, Yang X, Garate EG, Gota H, Korepanov S, Necas A, Roche T, Smirnov A, Trask E. Achieving a long-lived high-beta plasma state by energetic beam injection. Nat Commun 2015; 6:6897. [DOI: 10.1038/ncomms7897] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2014] [Accepted: 03/11/2015] [Indexed: 11/09/2022] Open
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11
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Haw M, Bellan P. 1D fast coded aperture camera. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2015; 86:043506. [PMID: 25933861 DOI: 10.1063/1.4917345] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2015] [Accepted: 03/31/2015] [Indexed: 06/04/2023]
Abstract
A fast (100 MHz) 1D coded aperture visible light camera has been developed as a prototype for imaging plasma experiments in the EUV/X-ray bands. The system uses printed patterns on transparency sheets as the masked aperture and an 80 channel photodiode array (9 V reverse bias) as the detector. In the low signal limit, the system has demonstrated 40-fold increase in throughput and a signal-to-noise gain of ≈7 over that of a pinhole camera of equivalent parameters. In its present iteration, the camera can only image visible light; however, the only modifications needed to make the system EUV/X-ray sensitive are to acquire appropriate EUV/X-ray photodiodes and to machine a metal masked aperture.
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Affiliation(s)
- Magnus Haw
- Department of Applied Physics and Materials Science, Caltech, 1200 E. California Blvd. MC 128-95, Pasadena, California 91125, USA
| | - Paul Bellan
- Department of Applied Physics and Materials Science, Caltech, 1200 E. California Blvd. MC 128-95, Pasadena, California 91125, USA
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12
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Chai KB, Bellan PM. Extreme ultra-violet movie camera for imaging microsecond time scale magnetic reconnection. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2013; 84:123504. [PMID: 24387431 DOI: 10.1063/1.4841915] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
An ultra-fast extreme ultra-violet (EUV) movie camera has been developed for imaging magnetic reconnection in the Caltech spheromak/astrophysical jet experiment. The camera consists of a broadband Mo:Si multilayer mirror, a fast decaying YAG:Ce scintillator, a visible light block, and a high-speed visible light CCD camera. The camera can capture EUV images as fast as 3.3 × 10(6) frames per second with 0.5 cm spatial resolution. The spectral range is from 20 eV to 60 eV. EUV images reveal strong, transient, highly localized bursts of EUV radiation when magnetic reconnection occurs.
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Affiliation(s)
- Kil-Byoung Chai
- Applied Physics, Caltech, 1200 E. California Boulevard, Pasadena, California 91125, USA
| | - Paul M Bellan
- Applied Physics, Caltech, 1200 E. California Boulevard, Pasadena, California 91125, USA
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Eyink G, Vishniac E, Lalescu C, Aluie H, Kanov K, Bürger K, Burns R, Meneveau C, Szalay A. Flux-freezing breakdown in high-conductivity magnetohydrodynamic turbulence. Nature 2013; 497:466-9. [DOI: 10.1038/nature12128] [Citation(s) in RCA: 124] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2012] [Accepted: 03/26/2013] [Indexed: 11/10/2022]
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