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Ji H, Yoo J, Fox W, Yamada M, Argall M, Egedal J, Liu YH, Wilder R, Eriksson S, Daughton W, Bergstedt K, Bose S, Burch J, Torbert R, Ng J, Chen LJ. Laboratory Study of Collisionless Magnetic Reconnection. Space Sci Rev 2023; 219:76. [PMID: 38023292 PMCID: PMC10651714 DOI: 10.1007/s11214-023-01024-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Accepted: 11/03/2023] [Indexed: 12/01/2023]
Abstract
A concise review is given on the past two decades' results from laboratory experiments on collisionless magnetic reconnection in direct relation with space measurements, especially by the Magnetospheric Multiscale (MMS) mission. Highlights include spatial structures of electromagnetic fields in ion and electron diffusion regions as a function of upstream symmetry and guide field strength, energy conversion and partitioning from magnetic field to ions and electrons including particle acceleration, electrostatic and electromagnetic kinetic plasma waves with various wavelengths, and plasmoid-mediated multiscale reconnection. Combined with the progress in theoretical, numerical, and observational studies, the physics foundation of fast reconnection in collisionless plasmas has been largely established, at least within the parameter ranges and spatial scales that were studied. Immediate and long-term future opportunities based on multiscale experiments and space missions supported by exascale computation are discussed, including dissipation by kinetic plasma waves, particle heating and acceleration, and multiscale physics across fluid and kinetic scales.
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Affiliation(s)
- H. Ji
- Department of Astrophysical Sciences, Princeton University, 4 Ivy Lane, Princeton, 08544 New Jersey USA
- Princeton Plasma Physics Laboratory, P.O. Box 451, Princeton, 08543 New Jersey USA
| | - J. Yoo
- Princeton Plasma Physics Laboratory, P.O. Box 451, Princeton, 08543 New Jersey USA
| | - W. Fox
- Princeton Plasma Physics Laboratory, P.O. Box 451, Princeton, 08543 New Jersey USA
| | - M. Yamada
- Princeton Plasma Physics Laboratory, P.O. Box 451, Princeton, 08543 New Jersey USA
| | - M. Argall
- Institute for the Study of Earth, Oceans, and Space, University of New Hampshire, 8 College Road, Durham, 03824 New Hampshire USA
| | - J. Egedal
- Department of Physics, University of Wisconsin - Madison, 1150 University Avenue, Madison, 53706 Wisconsin USA
| | - Y.-H. Liu
- Department of Physics and Astronomy, Dartmouth College, 17 Fayerweather Hill Road, Hanover, 03755 New Hampshire USA
| | - R. Wilder
- Department of Physics, University of Texas at Arlington, 701 S. Nedderman Drive, Arlington, 76019 Texas USA
| | - S. Eriksson
- Laboratory for Atmospheric and Space Physics, University of Colorado at Boulder, 1234 Innovation Drive, Boulder, 80303 Colorado USA
| | - W. Daughton
- Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, 87545 New Mexico USA
| | - K. Bergstedt
- Department of Astrophysical Sciences, Princeton University, 4 Ivy Lane, Princeton, 08544 New Jersey USA
| | - S. Bose
- Princeton Plasma Physics Laboratory, P.O. Box 451, Princeton, 08543 New Jersey USA
| | - J. Burch
- Southwest Research Institute, 6220 Culebra Road, San Antonio, 78238 Texas USA
| | - R. Torbert
- Institute for the Study of Earth, Oceans, and Space, University of New Hampshire, 8 College Road, Durham, 03824 New Hampshire USA
| | - J. Ng
- Princeton Plasma Physics Laboratory, P.O. Box 451, Princeton, 08543 New Jersey USA
- Department of Astronomy, University of Maryland, 4296 Stadium Drive, College Park, 20742 Maryland USA
- Goddard Space Flight Center, Mail Code 130, Greenbelt, 20771 Maryland USA
| | - L.-J. Chen
- Goddard Space Flight Center, Mail Code 130, Greenbelt, 20771 Maryland USA
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2
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Egedal J, Ng J, Le A, Daughton W, Wetherton B, Dorelli J, Gershman D, Rager A. Pressure Tensor Elements Breaking the Frozen-In Law During Reconnection in Earth's Magnetotail. Phys Rev Lett 2019; 123:225101. [PMID: 31868399 DOI: 10.1103/physrevlett.123.225101] [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: 12/20/2018] [Revised: 08/22/2019] [Indexed: 06/10/2023]
Abstract
Aided by fully kinetic simulations, spacecraft observations of magnetic reconnection in Earth's magnetotail are analyzed. The structure of the electron diffusion region is in quantitative agreement with the numerical model. Of special interest, the spacecraft data reveal how reconnection is mediated by off-diagonal stress in the electron pressure tensor breaking the frozen-in law of the electron fluid.
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Affiliation(s)
- J Egedal
- Department of Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - J Ng
- Center for Heliophysics, Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA
| | - A Le
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - W Daughton
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - B Wetherton
- Department of Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - J Dorelli
- Heliophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
| | - D Gershman
- Heliophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
| | - A Rager
- Heliophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
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3
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Jara-Almonte J, Ji H, Yoo J, Yamada M, Fox W, Daughton W. Kinetic Simulations of Magnetic Reconnection in Partially Ionized Plasmas. Phys Rev Lett 2019; 122:015101. [PMID: 31012658 DOI: 10.1103/physrevlett.122.015101] [Citation(s) in RCA: 1] [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: 08/31/2018] [Indexed: 06/09/2023]
Abstract
Fast magnetic reconnection occurs in nearly all natural and laboratory plasmas and rapidly releases stored magnetic energy. Although commonly studied in fully ionized plasmas, if and when fast reconnection can occur in partially ionized plasmas, such as the interstellar medium or solar chromosphere, is not well understood. This Letter presents the first fully kinetic particle-in-cell simulations of partially ionized reconnection and demonstrates that fast reconnection can occur in partially ionized systems. In the simulations, the transition to fast reconnection occurs when the current sheet width thins below the ion-inertial length in contrast to previous analytic predictions. The peak reconnection rate is ≥0.08 when normalized to the bulk Alfvén speed (including both ion and neutral mass), consistent with previous experimental results. However, when the bulk Alfvén speed falls below the neutral sound speed, the rate becomes system size dependent. The normalized inflow velocity is ionization fraction dependent, which is shown to be a result of neutral momentum transport. A model for the inflow is developed which agrees well with the simulation results.
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Affiliation(s)
- J Jara-Almonte
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA
| | - H Ji
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA
| | - J Yoo
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA
| | - M Yamada
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA
| | - W Fox
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA
| | - W Daughton
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
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4
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Egedal J, Le A, Daughton W, Wetherton B, Cassak PA, Burch JL, Lavraud B, Dorelli J, Gershman DJ, Avanov LA. Spacecraft Observations of Oblique Electron Beams Breaking the Frozen-In Law During Asymmetric Reconnection. Phys Rev Lett 2018; 120:055101. [PMID: 29481157 DOI: 10.1103/physrevlett.120.055101] [Citation(s) in RCA: 1] [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: 12/05/2017] [Indexed: 06/08/2023]
Abstract
Fully kinetic simulations of asymmetric magnetic reconnection reveal the presence of magnetic-field-aligned beams of electrons flowing toward the topological magnetic x line. Within the ∼6d_{e} electron-diffusion region, the beams become oblique to the local magnetic field, providing a unique signature of the electron-diffusion region where the electron frozen-in law is broken. The numerical predictions are confirmed by in situ Magnetospheric Multiscale spacecraft observations during asymmetric reconnection at Earth's dayside magnetopause.
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Affiliation(s)
- J Egedal
- Department of Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - A Le
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - W Daughton
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - B Wetherton
- Department of Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - P A Cassak
- Department of Physics and Astronomy, West Virginia University, Morgantown, West Virginia 26506, USA
| | - J L Burch
- Southwest Research Institute, San Antonio, Texas 78238, USA
| | - B Lavraud
- Institut de Recherche en Astrophysique et Planétologie, Université de Toulouse, UMR 5277, Toulouse, France
| | - J Dorelli
- Heliophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
| | - D J Gershman
- Heliophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
| | - L A Avanov
- Heliophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
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Nakamura TKM, Hasegawa H, Daughton W, Eriksson S, Li WY, Nakamura R. Turbulent mass transfer caused by vortex induced reconnection in collisionless magnetospheric plasmas. Nat Commun 2017; 8:1582. [PMID: 29150662 PMCID: PMC5693928 DOI: 10.1038/s41467-017-01579-0] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Accepted: 10/01/2017] [Indexed: 11/09/2022] Open
Abstract
Magnetic reconnection is believed to be the main driver to transport solar wind into the Earth's magnetosphere when the magnetopause features a large magnetic shear. However, even when the magnetic shear is too small for spontaneous reconnection, the Kelvin-Helmholtz instability driven by a super-Alfvénic velocity shear is expected to facilitate the transport. Although previous kinetic simulations have demonstrated that the non-linear vortex flows from the Kelvin-Helmholtz instability gives rise to vortex-induced reconnection and resulting plasma transport, the system sizes of these simulations were too small to allow the reconnection to evolve much beyond the electron scale as recently observed by the Magnetospheric Multiscale (MMS) spacecraft. Here, based on a large-scale kinetic simulation and its comparison with MMS observations, we show for the first time that ion-scale jets from vortex-induced reconnection rapidly decay through self-generated turbulence, leading to a mass transfer rate nearly one order higher than previous expectations for the Kelvin-Helmholtz instability.
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Affiliation(s)
- T K M Nakamura
- Space Research Institute, Austrian Academy of Sciences, 8010, Graz, Austria.
| | - H Hasegawa
- Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, Sagamihara, 252-5210, Japan
| | - W Daughton
- Los Alamos National Laboratory, Los Alamos, NM, 87545, USA
| | - S Eriksson
- Laboratory for Atmospheric and Space Physics, University of Colorado Boulder, Boulder, CO, 80303, USA
| | - W Y Li
- Swedish Institute of Space Physics, SE751-21, Uppsala, Sweden.,State Key Laboratory of Space Weather, National Space Science Center, Chinese Academy of Sciences, Beijing, 100190, China
| | - R Nakamura
- Space Research Institute, Austrian Academy of Sciences, 8010, Graz, Austria
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Yang Y, Matthaeus WH, Parashar TN, Wu P, Wan M, Shi Y, Chen S, Roytershteyn V, Daughton W. Energy transfer channels and turbulence cascade in Vlasov-Maxwell turbulence. Phys Rev E 2017; 95:061201. [PMID: 28709288 DOI: 10.1103/physreve.95.061201] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Indexed: 06/07/2023]
Abstract
Analysis of the Vlasov-Maxwell equations from the perspective of turbulence cascade clarifies the role of electromagnetic work, and reveals the importance of the pressure-strain relation in generating internal energy. Particle-in-cell simulation demonstrates the relative importance of the several energy exchange terms, indicating that the traceless pressure-strain interaction "Pi-D" is of particular importance for both electrons and protons. The Pi-D interaction and the second tensor invariants of the strain are highly localized in similar spatial regions, indicating that energy transfer occurs preferentially in coherent structures. The collisionless turbulence cascade may be fruitfully explored by study of these energy transfer channels, in addition to examining transfer across spatial scales.
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Affiliation(s)
- Yan Yang
- State Key Laboratory for Turbulence and Complex Systems, Center for Applied Physics and Technology, College of Engineering, Peking University, Beijing 100871, China
- Bartol Research Institute and Department of Physics and Astronomy, University of Delaware, Newark, Delaware 19716, USA
| | - W H Matthaeus
- Bartol Research Institute and Department of Physics and Astronomy, University of Delaware, Newark, Delaware 19716, USA
| | - T N Parashar
- Bartol Research Institute and Department of Physics and Astronomy, University of Delaware, Newark, Delaware 19716, USA
| | - P Wu
- Bartol Research Institute and Department of Physics and Astronomy, University of Delaware, Newark, Delaware 19716, USA
- School of Mathematics and Physics, Queen's University Belfast, BT7 1NN, United Kingdom
| | - M Wan
- Department of Mechanics and Aerospace Engineering, South University of Science and Technology of China, Shenzhen, Guangdong 518055, China
| | - Y Shi
- State Key Laboratory for Turbulence and Complex Systems, Center for Applied Physics and Technology, College of Engineering, Peking University, Beijing 100871, China
| | - S Chen
- State Key Laboratory for Turbulence and Complex Systems, Center for Applied Physics and Technology, College of Engineering, Peking University, Beijing 100871, China
- Department of Mechanics and Aerospace Engineering, South University of Science and Technology of China, Shenzhen, Guangdong 518055, China
| | | | - W Daughton
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
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Liu YH, Hesse M, Guo F, Daughton W, Li H, Cassak PA, Shay MA. Why does Steady-State Magnetic Reconnection have a Maximum Local Rate of Order 0.1? Phys Rev Lett 2017; 118:085101. [PMID: 28282209 DOI: 10.1103/physrevlett.118.085101] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Indexed: 06/06/2023]
Abstract
Simulations suggest collisionless steady-state magnetic reconnection of Harris-type current sheets proceeds with a rate of order 0.1, independent of dissipation mechanism. We argue this long-standing puzzle is a result of constraints at the magnetohydrodynamic (MHD) scale. We predict the reconnection rate as a function of the opening angle made by the upstream magnetic fields, finding a maximum reconnection rate close to 0.2. The predictions compare favorably to particle-in-cell simulations of relativistic electron-positron and nonrelativistic electron-proton reconnection. The fact that simulated reconnection rates are close to the predicted maximum suggests reconnection proceeds near the most efficient state allowed at the MHD scale. The rate near the maximum is relatively insensitive to the opening angle, potentially explaining why reconnection has a similar fast rate in differing models.
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Affiliation(s)
- Yi-Hsin Liu
- NASA-Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
| | - M Hesse
- NASA-Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
| | - F Guo
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - W Daughton
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - H Li
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - P A Cassak
- West Virginia University, Morgantown, West Virginia 26506, USA
| | - M A Shay
- University of Delaware, Newark, Delaware 19716, USA
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8
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Egedal J, Le A, Daughton W, Wetherton B, Cassak PA, Chen LJ, Lavraud B, Torbert RB, Dorelli J, Gershman DJ, Avanov LA. Spacecraft Observations and Analytic Theory of Crescent-Shaped Electron Distributions in Asymmetric Magnetic Reconnection. Phys Rev Lett 2016; 117:185101. [PMID: 27835028 PMCID: PMC7437547 DOI: 10.1103/physrevlett.117.185101] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Indexed: 06/06/2023]
Abstract
Supported by a kinetic simulation, we derive an exclusion energy parameter E_{X} providing a lower kinetic energy bound for an electron to cross from one inflow region to the other during magnetic reconnection. As by a Maxwell demon, only high-energy electrons are permitted to cross the inner reconnection region, setting the electron distribution function observed along the low-density side separatrix during asymmetric reconnection. The analytic model accounts for the two distinct flavors of crescent-shaped electron distributions observed by spacecraft in a thin boundary layer along the low-density separatrix.
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Affiliation(s)
- J Egedal
- Department of Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - A Le
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - W Daughton
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - B Wetherton
- Department of Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - P A Cassak
- Department of Physics and Astronomy, West Virginia University, Morgantown, West Virginia 26506, USA
| | - L-J Chen
- Heliophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
| | - B Lavraud
- Institut de Recherche en Astrophysique et Planétologie, Université de Toulouse, Toulouse, France, and Centre National de la Recherche Scientifique, UMR 5277, Toulouse, France
| | - R B Torbert
- University of New Hampshire, Durham, New Hampshire 03824, USA
| | - J Dorelli
- Heliophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
| | - D J Gershman
- Heliophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
| | - L A Avanov
- Heliophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
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9
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Gekelman W, De Haas T, Daughton W, Van Compernolle B, Intrator T, Vincena S. Pulsating Magnetic Reconnection Driven by Three-Dimensional Flux-Rope Interactions. Phys Rev Lett 2016; 116:235101. [PMID: 27341240 DOI: 10.1103/physrevlett.116.235101] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Indexed: 06/06/2023]
Abstract
The dynamics of magnetic reconnection is investigated in a laboratory experiment consisting of two magnetic flux ropes, with currents slightly above the threshold for the kink instability. The evolution features periodic bursts of magnetic reconnection. To diagnose this complex evolution, volumetric three-dimensional data were acquired for both the magnetic and electric fields, allowing key field-line mapping quantities to be directly evaluated for the first time with experimental data. The ropes interact by rotating about each other and periodically bouncing at the kink frequency. During each reconnection event, the formation of a quasiseparatrix layer (QSL) is observed in the magnetic field between the flux ropes. Furthermore, a clear correlation is demonstrated between the quasiseparatrix layer and enhanced values of the quasipotential computed by integrating the parallel electric field along magnetic field lines. These results provide clear evidence that field lines passing through the quasiseparatrix layer are undergoing reconnection and give a direct measure of the nonlinear reconnection rate. The measurements suggest that the parallel electric field within the QSL is supported predominantly by electron pressure; however, resistivity may play a role.
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Affiliation(s)
- W Gekelman
- Department of Physics, University of California, Los Angeles, Los Angeles, California 90095, USA
| | - T De Haas
- Department of Physics, University of California, Los Angeles, Los Angeles, California 90095, USA
| | - W Daughton
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - B Van Compernolle
- Department of Physics, University of California, Los Angeles, Los Angeles, California 90095, USA
| | - T Intrator
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - S Vincena
- Department of Physics, University of California, Los Angeles, Los Angeles, California 90095, USA
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10
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Stanier A, Daughton W, Chacón L, Karimabadi H, Ng J, Huang YM, Hakim A, Bhattacharjee A. Role of Ion Kinetic Physics in the Interaction of Magnetic Flux Ropes. Phys Rev Lett 2015; 115:175004. [PMID: 26551121 DOI: 10.1103/physrevlett.115.175004] [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: 07/21/2015] [Indexed: 06/05/2023]
Abstract
To explain many natural magnetized plasma phenomena, it is crucial to understand how rates of collisionless magnetic reconnection scale in large magnetohydrodynamic (MHD) scale systems. Simulations of isolated current sheets conclude such rates are independent of system size and can be reproduced by the Hall-MHD model, but neglect sheet formation and coupling to MHD scales. Here, it is shown for the problem of flux-rope merging, which includes this formation and coupling, that the Hall-MHD model fails to reproduce the kinetic results. The minimum sufficient model must retain ion kinetic effects, which set the ion diffusion region geometry and give time-averaged rates that reduce significantly with system size, leading to different global evolution in large systems.
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Affiliation(s)
- A Stanier
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - W Daughton
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - L Chacón
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - H Karimabadi
- SciberQuest, Inc., Del Mar, California 92014, USA
| | - J Ng
- Center for Heliophysics, Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA
| | - Y-M Huang
- Center for Heliophysics, Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA
| | - A Hakim
- Center for Heliophysics, Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA
| | - A Bhattacharjee
- Center for Heliophysics, Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA
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11
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Liu YH, Daughton W, Karimabadi H, Li H, Roytershteyn V. Bifurcated structure of the electron diffusion region in three-dimensional magnetic reconnection. Phys Rev Lett 2013; 110:265004. [PMID: 23848886 DOI: 10.1103/physrevlett.110.265004] [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: 01/02/2013] [Indexed: 06/02/2023]
Abstract
Three-dimensional kinetic simulations of magnetic reconnection reveal that the electron diffusion region is composed of two or more current sheets in regimes with weak magnetic shear angles ϕ≲80°. This new morphology is explained by oblique tearing modes which produce flux ropes while simultaneously driving enhanced current at multiple resonance surfaces. This physics persists into the nonlinear regime leading to multiple electron layers embedded within a larger Alfvénic inflow and outflow. Surprisingly, the thickness of these layers and the reconnection rate both remain comparable to two-dimensional models. The parallel electric fields are supported predominantly by the electron pressure tensor and electron inertia, while turbulent dissipation remains small.
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Affiliation(s)
- Yi-Hsin Liu
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
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12
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Leonardis E, Chapman SC, Daughton W, Roytershteyn V, Karimabadi H. Identification of intermittent multifractal turbulence in fully kinetic simulations of magnetic reconnection. Phys Rev Lett 2013; 110:205002. [PMID: 25167422 DOI: 10.1103/physrevlett.110.205002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/19/2012] [Indexed: 06/03/2023]
Abstract
Recent fully nonlinear, kinetic three-dimensional simulations of magnetic reconnection [W. Daughton et al., Nat. Phys. 7, 539 (2011)] evolve structures and exhibit dynamics on multiple scales, in a manner reminiscent of turbulence. These simulations of reconnection are among the first to be performed at sufficient spatiotemporal resolution to allow formal quantitative analysis of statistical scaling, which we present here. We find that the magnetic field fluctuations generated by reconnection are anisotropic, have nontrivial spatial correlation, and exhibit the hallmarks of finite range fluid turbulence: they have non-Gaussian distributions, exhibit extended self-similarity in their scaling, and are spatially multifractal. Furthermore, we find that the rate at which the fields do work on the particles, J · E, is also multifractal, so that magnetic energy is converted to plasma kinetic energy in a manner that is spatially intermittent. This suggests that dissipation in this sense in collisionless reconnection on kinetic scales has an analogue in fluidlike turbulent phenomenology, in that it proceeds via multifractal structures generated by an intermittent cascade.
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Affiliation(s)
- E Leonardis
- Department of Physics, Centre for Fusion, Space and Astrophysics, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - S C Chapman
- Department of Physics, Centre for Fusion, Space and Astrophysics, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - W Daughton
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - V Roytershteyn
- University of California, San Diego, La Jolla, California 92093, USA
| | - H Karimabadi
- University of California, San Diego, La Jolla, California 92093, USA
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13
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Le A, Egedal J, Ohia O, Daughton W, Karimabadi H, Lukin VS. Regimes of the electron diffusion region in magnetic reconnection. Phys Rev Lett 2013; 110:135004. [PMID: 23581331 DOI: 10.1103/physrevlett.110.135004] [Citation(s) in RCA: 3] [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] [Received: 11/20/2012] [Indexed: 06/02/2023]
Abstract
The electron diffusion region during magnetic reconnection lies in different regimes depending on the pressure anisotropy, which is regulated by the properties of thermal electron orbits. In kinetic simulations at the weakest guide fields, pitch angle mixing in velocity space causes the outflow electron pressure to become nearly isotropic. Above a threshold guide field that depends on a range of parameters, including the normalized electron pressure and the ion-to-electron mass ratio, electron pressure anisotropy develops in the exhaust and supports extended current layers. This new regime with electron current sheets extending to the system size is also reproduced by fluid simulations with an anisotropic closure for the electron pressure. It offers an explanation for recent spacecraft observations.
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Affiliation(s)
- A Le
- Department of Physics, Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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14
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Wan M, Matthaeus WH, Karimabadi H, Roytershteyn V, Shay M, Wu P, Daughton W, Loring B, Chapman SC. Intermittent dissipation at kinetic scales in collisionless plasma turbulence. Phys Rev Lett 2012; 109:195001. [PMID: 23215389 DOI: 10.1103/physrevlett.109.195001] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2012] [Indexed: 06/01/2023]
Abstract
High resolution kinetic simulations of collisionless plasma driven by shear show the development of turbulence characterized by dynamic coherent sheetlike current density structures spanning a range of scales down to electron scales. We present evidence that these structures are sites for heating and dissipation, and that stronger current structures signify higher dissipation rates. Evidently, kinetic scale plasma, like magnetohydrodynamics, becomes intermittent due to current sheet formation, leading to the expectation that heating and dissipation in astrophysical and space plasmas may be highly nonuniform and patchy.
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Affiliation(s)
- M Wan
- Bartol Research Institute and Department of Physics and Astronomy, University of Delaware, Newark, Delaware 19716, USA
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Ohia O, Egedal J, Lukin VS, Daughton W, Le A. Demonstration of anisotropic fluid closure capturing the kinetic structure of magnetic reconnection. Phys Rev Lett 2012; 109:115004. [PMID: 23005640 DOI: 10.1103/physrevlett.109.115004] [Citation(s) in RCA: 3] [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] [Received: 04/14/2012] [Indexed: 06/01/2023]
Abstract
Collisionless magnetic reconnection in high-temperature plasmas has been widely studied through fluid-based models. Here, we present results of fluid simulation implementing new equations of state for guide-field reconnection. The new fluid closure accurately accounts for the anisotropic electron pressure that builds in the reconnection region due to electric and magnetic trapping of electrons. In contrast to previous fluid models, our fluid simulation reproduces the detailed reconnection region as observed in fully kinetic simulations. We hereby demonstrate that the new fluid closure self-consistently captures all the physics relevant to the structure of the reconnection region, providing a gateway to a renewed and deeper theoretical understanding of reconnection in weakly collisional regimes.
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Affiliation(s)
- O Ohia
- Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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16
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Roytershteyn V, Daughton W, Karimabadi H, Mozer FS. Influence of the lower-hybrid drift instability on magnetic reconnection in asymmetric configurations. Phys Rev Lett 2012; 108:185001. [PMID: 22681084 DOI: 10.1103/physrevlett.108.185001] [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: 09/13/2011] [Indexed: 06/01/2023]
Abstract
Using fully kinetic 3D simulations of magnetic reconnection in asymmetric antiparallel configurations, we demonstrate that an electromagnetic lower-hybrid drift instability (LHDI) localized near the X line can substantially modify the reconnection mechanism in the regimes with large asymmetry, a moderate ratio of electron to ion temperature, and low plasma β. However, the mode saturates at a small amplitude in the regimes typical of Earth's magnetopause. In these cases, LHDI-driven turbulence is predominantly localized along the separatrices on the low-β side of the current sheet, in agreement with spacecraft observations.
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Affiliation(s)
- V Roytershteyn
- University of California, San Diego, La Jolla, California 92093, USA
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17
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Øieroset M, Phan TD, Eastwood JP, Fujimoto M, Daughton W, Shay MA, Angelopoulos V, Mozer FS, McFadden JP, Larson DE, Glassmeier KH. Direct evidence for a three-dimensional magnetic flux rope flanked by two active magnetic reconnection X lines at Earth's magnetopause. Phys Rev Lett 2011; 107:165007. [PMID: 22107399 DOI: 10.1103/physrevlett.107.165007] [Citation(s) in RCA: 2] [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: 06/20/2011] [Indexed: 05/31/2023]
Abstract
We report the direct detection by three THEMIS spacecraft of a magnetic flux rope flanked by two active X lines producing colliding plasma jets near the center of the flux rope. The observed density depletion and open magnetic field topology inside the flux rope reveal important three-dimensional effects. There was also evidence for nonthermal electron energization within the flux rope core where the fluxes of 1-4 keV superthermal electrons were higher than those in the converging reconnection jets. The observed ion and electron energizations differ from current theoretical predictions.
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Affiliation(s)
- M Øieroset
- Space Sciences Laboratory, University of California, Berkeley, Berkeley, California 94720, USA
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18
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Karimabadi H, Dorelli J, Roytershteyn V, Daughton W, Chacón L. Flux pileup in collisionless magnetic reconnection: bursty interaction of large flux ropes. Phys Rev Lett 2011; 107:025002. [PMID: 21797613 DOI: 10.1103/physrevlett.107.025002] [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] [Received: 03/10/2011] [Indexed: 05/31/2023]
Abstract
Using fully kinetic simulations of the island coalescence problem for a range of system sizes greatly exceeding kinetic scales, the phenomenon of flux pileup in the collisionless regime is demonstrated. While small islands on the scale of λ ≤ 5 ion inertial length (d(i)) coalesce rapidly and do not support significant flux pileup, coalescence of larger islands is characterized by large flux pileup and a weaker time averaged reconnection rate that scales as √(d(i)/λ) while the peak rate remains nearly independent of island size. For the largest islands (λ = 100d(i)), reconnection is bursty and nearly shuts off after the first bounce, reconnecting ~20% of the available flux.
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Affiliation(s)
- H Karimabadi
- University of California at San Diego, La Jolla, California 92093, USA
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Ng J, Egedal J, Le A, Daughton W, Chen LJ. Kinetic structure of the electron diffusion region in antiparallel magnetic reconnection. Phys Rev Lett 2011; 106:065002. [PMID: 21405472 DOI: 10.1103/physrevlett.106.065002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2010] [Indexed: 05/30/2023]
Abstract
Strong electron pressure anisotropy has been observed upstream of electron diffusion regions during reconnection in Earth's magnetotail and kinetic simulations. For collisionless antiparallel reconnection, we find that the anisotropy drives the electron current in the electron diffusion region, and that this current is insensitive to the reconnection electric field. Reconstruction of the electron distribution function within this region at enhanced resolutions reveals its highly structured nature and the mechanism by which the pressure anisotropy sets the structure of the region.
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Affiliation(s)
- J Ng
- Department of Physics, and Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
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Bowers KJ, Albright BJ, Yin L, Daughton W, Roytershteyn V, Bergen B, Kwan TJT. Advances in petascale kinetic plasma simulation with VPIC and Roadrunner. ACTA ACUST UNITED AC 2009. [DOI: 10.1088/1742-6596/180/1/012055] [Citation(s) in RCA: 120] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Daughton W, Roytershteyn V, Albright BJ, Karimabadi H, Yin L, Bowers KJ. Transition from collisional to kinetic regimes in large-scale reconnection layers. Phys Rev Lett 2009; 103:065004. [PMID: 19792577 DOI: 10.1103/physrevlett.103.065004] [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] [Received: 02/10/2009] [Indexed: 05/28/2023]
Abstract
Using fully kinetic simulations with a Fokker-Planck collision operator, it is demonstrated that Sweet-Parker reconnection layers are unstable to plasmoids (secondary islands) for Lundquist numbers beyond S greater, similar 1000. The instability is increasingly violent at higher Lundquist numbers, both in terms of the number of plasmoids produced and the super-Alfvénic growth rate. A dramatic enhancement in the reconnection rate is observed when the half-thickness of the current sheet between two plasmoids approaches the ion inertial length. During this transition to kinetic scales, the reconnection electric field rapidly exceeds the runaway limit, resulting in the formation of electron-scale current layers that are unstable to the continual formation of new plasmoids.
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Affiliation(s)
- W Daughton
- Los Alamos National Laboratory, Los Alamos, New Mexico 87544, USA
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22
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Le A, Egedal J, Daughton W, Fox W, Katz N. Equations of state for collisionless guide-field reconnection. Phys Rev Lett 2009; 102:085001. [PMID: 19257745 DOI: 10.1103/physrevlett.102.085001] [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: 11/26/2008] [Indexed: 05/27/2023]
Abstract
Direct in situ observation of magnetic reconnection in the Earth's magnetotail as well as kinetic numerical studies have recently shown that the electron pressure in a collisionless reconnection region is strongly anisotropic. This anisotropy is mainly caused by the trapping of electrons in parallel electric fields. We present new equations of state for the parallel and perpendicular pressures for magnetized electrons. This model-derived here and tested against a kinetic simulation-allows a fluid description in a collisionless regime where parallel electric fields and the dynamics of both passing and trapped electrons are essential.
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Affiliation(s)
- A Le
- Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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Yin L, Daughton W, Karimabadi H, Albright BJ, Bowers KJ, Margulies J. Three-dimensional dynamics of collisionless magnetic reconnection in large-scale pair plasmas. Phys Rev Lett 2008; 101:125001. [PMID: 18851379 DOI: 10.1103/physrevlett.101.125001] [Citation(s) in RCA: 2] [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] [Received: 02/01/2008] [Indexed: 05/26/2023]
Abstract
Using the largest three-dimensional particle-in-cell simulations to date, collisionless magnetic reconnection in large-scale electron-positron plasmas without a guide field is shown to involve complex interaction of tearing and kink modes. The reconnection onset is patchy and occurs at multiple sites which self-organize to form a single, large diffusion region. The diffusion region tends to elongate in the outflow direction and become unstable to secondary kinking and formation of "plasmoid-rope" structures with finite extent in the current direction. The secondary kink folds the reconnection current layer, while plasmoid ropes at times follow the folding of the current layer. The interplay between these secondary instabilities plays a key role in controlling the time-dependent reconnection rate in large-scale systems.
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Affiliation(s)
- L Yin
- Los Alamos National Laboratory, Los Alamos, NM 87544, USA
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Yin L, Albright BJ, Bowers KJ, Daughton W, Rose HA. Saturation of backward stimulated scattering of a laser beam in the kinetic regime. Phys Rev Lett 2007; 99:265004. [PMID: 18233584 DOI: 10.1103/physrevlett.99.265004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2007] [Indexed: 05/25/2023]
Abstract
Stimulated Raman (SRS) and Brillouin scattering (SBS) are examined in the kinetic regime using particle-in-cell simulations. Wave front bowing of electron-plasma waves (ion-acoustic waves) from trapped particle nonlinear frequency shift is observed in the SRS (SBS) regime for the first time. Self-focusing from trapped particle modulational instability (TPMI) is shown to occur in 2D and 3D SRS simulations. The key physics of SRS saturation is identified as a combination of wave front bowing, TPMI, and self-focusing: Bowing marks the beginning of SRS saturation and self-focusing terminates SRS. Ion-acoustic wave bowing also contributes to SBS saturation. Velocity diffusion by transverse modes and rapid loss of hot electrons in regions of small transverse extent formed from self-focusing dissipate wave energy and increase Landau damping, despite trapping that reduces Landau damping initially.
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Affiliation(s)
- L Yin
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
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Albright BJ, Daughton W, Yin L, Bowers KJ, Kline JL, Montgomery DS, Fernández JC. Particle-in-cell studies of laser-driven hot spots and a statistical model for mesoscopic properties of Raman backscatter. ACTA ACUST UNITED AC 2006. [DOI: 10.1051/jp4:2006133051] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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26
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Yin L, Daughton W, Albright BJ, Bezzerides B, DuBois DF, Kindel JM, Vu HX. Nonlinear development of stimulated Raman scattering from electrostatic modes excited by self-consistent non-Maxwellian velocity distributions. Phys Rev E Stat Nonlin Soft Matter Phys 2006; 73:025401. [PMID: 16605389 DOI: 10.1103/physreve.73.025401] [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: 11/24/2004] [Indexed: 05/08/2023]
Abstract
The parametric coupling involving backward stimulated scattering of a laser and electron beam acoustic modes (BAM) is described as observed in particle-in-cell (PIC) simulations. The BAM modes evolve from Langmuir waves (LW) as the electron velocity distribution is nonlinearly modified to be non-Maxwellian by backward stimulated Raman scattering (BSRS). With a marginal damping rate, BAM can be easily excited and allow an extended chirping in frequency to occur as later SRS pulses encounter modified distributions. Coincident with the emergence of this non-Maxwellian distribution is a rapid increase in BSRS reflectivities with laser intensities. Both the reflectivity scaling with laser intensity and the observed spectral features from PIC simulations are consistent with recent Trident experiments.
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Affiliation(s)
- L Yin
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
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Daughton W, Murillo MS, Thode L. Empirical bridge function for strongly coupled yukawa systems. Phys Rev E Stat Phys Plasmas Fluids Relat Interdiscip Topics 2000; 61:2129-2132. [PMID: 11046512 DOI: 10.1103/physreve.61.2129] [Citation(s) in RCA: 6] [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] [Received: 08/13/1999] [Indexed: 05/23/2023]
Abstract
A simple bridge function for strongly coupled Yukawa systems is developed based upon a form previously extracted for a one-component plasma [H. Iyetomi, S. Ogata, and S. Ichimaru, Phys. Rev. A 46, 1051 (1992)]. Using the proposed bridge function in the modified hypernetted chain theory, excellent agreement is obtained with molecular dynamics simulations and the compressibility sum rule is satisfied to within a few percent. This result offers a simple and very accurate method to quickly compute correlation functions for Yukawa systems.
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Affiliation(s)
- W Daughton
- Plasma Physics Group, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
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