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Richard L, Khotyaintsev YV, Graham DB, Vaivads A, Gershman DJ, Russell CT. Fast Ion Isotropization by Current Sheet Scattering in Magnetic Reconnection Jets. PHYSICAL REVIEW LETTERS 2023; 131:115201. [PMID: 37774258 DOI: 10.1103/physrevlett.131.115201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Revised: 06/22/2023] [Accepted: 08/07/2023] [Indexed: 10/01/2023]
Abstract
We present a statistical analysis of ion distributions in magnetic reconnection jets using data from the Magnetospheric Multiscale spacecraft. Compared with the quiet plasma in which the jet propagates, we often find anisotropic and non-Maxwellian ion distributions in the plasma jets. We observe magnetic field fluctuations associated with unstable ion distributions, but the wave amplitudes are not large enough to scatter ions during the observed travel time of the jet. We estimate that the phase-space diffusion due to chaotic and quasiadiabatic ion motion in the current sheet is sufficiently fast to be the primary process leading to isotropization.
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Affiliation(s)
- Louis Richard
- Swedish Institute of Space Physics, Uppsala 751 21, Sweden and Department of Physics and Astronomy, Space and Plasma Physics, Uppsala University, Uppsala 751 20, Sweden
| | | | | | - Andris Vaivads
- Division of Space and Plasma Physics, KTH Royal Institute of Technology, Stockholm 100 44, Sweden, and Ventspils University of Applied Sciences, Ventspils 3601, Latvia
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Angelopoulos V, Artemyev A, Phan TD, Miyashita Y. Near-Earth Magnetotail Reconnection Powers Space Storms. NATURE PHYSICS 2020; 2020:10.1038/s41567-019-0749-4. [PMID: 32021641 PMCID: PMC6999787 DOI: 10.1038/s41567-019-0749-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Accepted: 11/12/2019] [Indexed: 06/10/2023]
Affiliation(s)
- Vassilis Angelopoulos
- Earth, Planetary and Space Sciences, and Institute of Geophysics and Space Physics, University of California, Los Angeles, CA 90095, USA
| | - Anton Artemyev
- Earth, Planetary and Space Sciences, and Institute of Geophysics and Space Physics, University of California, Los Angeles, CA 90095, USA
| | - Tai D. Phan
- Space Sciences Laboratory, University of California, Berkeley, CA 94720, USA
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The two-fluid dynamics and energetics of the asymmetric magnetic reconnection in laboratory and space plasmas. Nat Commun 2018; 9:5223. [PMID: 30523290 PMCID: PMC6283883 DOI: 10.1038/s41467-018-07680-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Accepted: 10/29/2018] [Indexed: 11/16/2022] Open
Abstract
Magnetic reconnection is a fundamental process in magnetized plasma where magnetic energy is converted to plasma energy. Despite huge differences in the physical size of the reconnection layer, remarkably similar characteristics are observed in both laboratory and magnetosphere plasmas. Here we present the comparative study of the dynamics and physical mechanisms governing the energy conversion in the laboratory and space plasma in the context of two-fluid physics, aided by numerical simulations. In strongly asymmetric reconnection layers with negligible guide field, the energy deposition to electrons is found to primarily occur in the electron diffusion region where electrons are demagnetized and diffuse. A large potential well is observed within the reconnection plane and ions are accelerated by the electric field toward the exhaust region. The present comparative study identifies the robust two-fluid mechanism operating in systems over six orders of magnitude in spatial scales and over a wide range of collisionality. Magnetic energy in the plasma is transferred into particle energy by magnetic reconnection. Here the authors show the two-fluid dynamics of asymmetric magnetic reconnection in two different spatial scales of plasma, namely laboratory and astrophysical plasma.
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Hietala H, Drake JF, Phan TD, Eastwood JP, McFadden JP. Ion temperature anisotropy across a magnetotail reconnection jet. GEOPHYSICAL RESEARCH LETTERS 2015; 42:7239-7247. [PMID: 27478283 PMCID: PMC4950132 DOI: 10.1002/2015gl065168] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Revised: 08/17/2015] [Accepted: 08/19/2015] [Indexed: 06/02/2023]
Abstract
A significant fraction of the energy released by magnetotail reconnection appears to go into ion heating, but this heating is generally anisotropic. We examine ARTEMIS dual-spacecraft observations of a long-duration magnetotail exhaust generated by antiparallel reconnection in conjunction with particle-in-cell simulations, showing spatial variations in the anisotropy across the outflow far (>100di ) downstream of the X line. A consistent pattern is found in both the spacecraft data and the simulations: While the total temperature across the exhaust is rather constant, near the boundaries Ti,|| dominates. The plasma is well above the firehose threshold within patchy spatial regions at |BX |∈[0.1,0.5]B0, suggesting that the drive for the instability is strong and the instability is too weak to relax the anisotropy. At the midplane ( |BX|≲0.1B0), Ti,⊥>Ti,|| and ions undergo Speiser-like motion despite the large distance from the X line.
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Affiliation(s)
- H. Hietala
- The Blackett LaboratoryImperial CollegeLondonUK
| | - J. F. Drake
- Department of Physics, the Institute for Physical Science and Technology and the Joint Space InstituteUniversity of MarylandCollege ParkMarylandUSA
| | - T. D. Phan
- Space Science LaboratoryUniversity of CaliforniaBerkeleyCaliforniaUSA
| | | | - J. P. McFadden
- Space Science LaboratoryUniversity of CaliforniaBerkeleyCaliforniaUSA
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Hoshino M. Angular momentum transport and particle acceleration during magnetorotational instability in a kinetic accretion disk. PHYSICAL REVIEW LETTERS 2015; 114:061101. [PMID: 25723200 DOI: 10.1103/physrevlett.114.061101] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2014] [Indexed: 06/04/2023]
Abstract
Angular momentum transport and particle acceleration during the magnetorotational instability (MRI) in a collisionless accretion disk are investigated using three-dimensional particle-in-cell simulation. We show that the kinetic MRI can provide not only high-energy particle acceleration but also enhancement of angular momentum transport. We find that the plasma pressure anisotropy inside the channel flow with p(∥)>p(⊥) induced by active magnetic reconnection suppresses the onset of subsequent reconnection, which, in turn, leads to high-magnetic-field saturation and enhancement of the Maxwell stress tensor of angular momentum transport. Meanwhile, during the quiescent stage of reconnection, the plasma isotropization progresses in the channel flow and the anisotropic plasma with p(⊥)>p(∥) due to the dynamo action of MRI outside the channel flow contribute to rapid reconnection and strong particle acceleration. This efficient particle acceleration and enhanced angular momentum transport in a collisionless accretion disk may explain the origin of high-energy particles observed around massive black holes.
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Affiliation(s)
- Masahiro Hoshino
- Department of Earth and Planetary Science, University of Tokyo, Tokyo 113-0033, Japan
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Yoo J, Yamada M, Ji H, Myers CE. Observation of ion acceleration and heating during collisionless magnetic reconnection in a laboratory plasma. PHYSICAL REVIEW LETTERS 2013; 110:215007. [PMID: 23745892 DOI: 10.1103/physrevlett.110.215007] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2012] [Indexed: 06/02/2023]
Abstract
The ion dynamics in a collisionless magnetic reconnection layer are studied in a laboratory plasma. The measured in-plane plasma potential profile, which is established by electrons accelerated around the electron diffusion region, shows a saddle-shaped structure that is wider and deeper towards the outflow direction. This potential structure ballistically accelerates ions near the separatrices toward the outflow direction. Ions are heated as they travel into the high-pressure downstream region.
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Affiliation(s)
- Jongsoo Yoo
- Center for Magnetic Self-organization in Laboratory and Astrophysical Plasmas, Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA.
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Mukai T, Yamamoto T, Machida S. Dynamics and Kinetic Properties of Plasmoids and Flux Ropes: GEOTAIL Observations. NEW PERSPECTIVES ON THE EARTH'S MAGNETOTAIL 2013. [DOI: 10.1029/gm105p0117] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
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Aunai N, Belmont G, Smets R. Proton acceleration in antiparallel collisionless magnetic reconnection: Kinetic mechanisms behind the fluid dynamics. ACTA ACUST UNITED AC 2011. [DOI: 10.1029/2011ja016688] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- N. Aunai
- Laboratoire de Physique des Plasmas, Ecole Polytechnique; Palaiseau France
| | - G. Belmont
- Laboratoire de Physique des Plasmas, Ecole Polytechnique; Palaiseau France
| | - R. Smets
- Laboratoire de Physique des Plasmas, Ecole Polytechnique; Palaiseau France
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Wygant JR, Cattell CA, Lysak R, Song Y, Dombeck J, McFadden J, Mozer FS, Carlson CW, Parks G, Lucek EA, Balogh A, Andre M, Reme H, Hesse M, Mouikis C. Cluster observations of an intense normal component of the electric field at a thin reconnecting current sheet in the tail and its role in the shock-like acceleration of the ion fluid into the separatrix region. ACTA ACUST UNITED AC 2005. [DOI: 10.1029/2004ja010708] [Citation(s) in RCA: 227] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- J. R. Wygant
- School of Physics and Astronomy; University of Minnesota; Minneapolis Minnesota USA
| | - C. A. Cattell
- School of Physics and Astronomy; University of Minnesota; Minneapolis Minnesota USA
| | - R. Lysak
- School of Physics and Astronomy; University of Minnesota; Minneapolis Minnesota USA
| | - Y. Song
- School of Physics and Astronomy; University of Minnesota; Minneapolis Minnesota USA
| | - J. Dombeck
- School of Physics and Astronomy; University of Minnesota; Minneapolis Minnesota USA
| | - J. McFadden
- Space Sciences Laboratory; University of California; Berkeley California USA
| | - F. S. Mozer
- Space Sciences Laboratory; University of California; Berkeley California USA
| | - C. W. Carlson
- Space Sciences Laboratory; University of California; Berkeley California USA
| | - G. Parks
- Space Sciences Laboratory; University of California; Berkeley California USA
| | - E. A. Lucek
- Blackett Laboratory; Imperial College; London UK
| | - A. Balogh
- Blackett Laboratory; Imperial College; London UK
| | - M. Andre
- Swedish Institute of Space Physics; Uppsala Division; Uppsala Sweden
| | - H. Reme
- Centre d'Etude Spatiale des Rayonnements; Toulouse France
| | - M. Hesse
- NASA Goddard Space Flight Center; Greenbelt Maryland USA
| | - C. Mouikis
- University of New Hampshire; Durham New Hampshire USA
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Seki K, Hirahara M, Hoshino M, Terasawa T, Elphic RC, Saito Y, Mukai T, Hayakawa H, Kojima H, Matsumoto H. Cold ions in the hot plasma sheet of Earth's magnetotail. Nature 2003; 422:589-92. [PMID: 12686993 DOI: 10.1038/nature01502] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2002] [Accepted: 02/18/2003] [Indexed: 11/08/2022]
Abstract
Most visible matter in the Universe exists as plasma. How this plasma is heated, and especially how the initial non-equilibrium plasma distributions relax to thermal equilibrium (as predicted by Maxwell-Boltzman statistics), is a fundamental question in studies of astrophysical and laboratory plasmas. Astrophysical plasmas are often so tenuous that binary collisions can be ignored, and it is not clear how thermal equilibrium develops for these 'collisionless' plasmas. One example of a collisionless plasma is the Earth's plasma sheet, where thermalized hot plasma with ion temperatures of about 5 x 10(7) K has been observed. Here we report direct observations of a plasma distribution function during a solar eclipse, revealing cold ions in the Earth's plasma sheet in coexistence with thermalized hot ions. This cold component cannot be detected by plasma sensors on satellites that are positively charged in sunlight, but our observations in the Earth's shadow show that the density of the cold ions is comparable to that of hot ions. This high density is difficult to explain within existing theories, as it requires a mechanism that permits half of the source plasma to remain cold upon entry into the hot turbulent plasma sheet.
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Affiliation(s)
- Kanako Seki
- Solar-Terrestrial Environment Laboratory, Nagoya University, Honohara 3-13, Toyokawa, Aichi 442-8507, Japan.
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Nagai T, Shinohara I, Fujimoto M, Hoshino M, Saito Y, Machida S, Mukai T. Geotail observations of the Hall current system: Evidence of magnetic reconnection in the magnetotail. ACTA ACUST UNITED AC 2001. [DOI: 10.1029/2001ja900038] [Citation(s) in RCA: 268] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Hoshino M, Mukai T, Terasawa T, Shinohara I. Suprathermal electron acceleration in magnetic reconnection. ACTA ACUST UNITED AC 2001. [DOI: 10.1029/2001ja900052] [Citation(s) in RCA: 278] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Oieroset M, Phan TD, Fujimoto M, Lin RP, Lepping RP. In situ detection of collisionless reconnection in the Earth's magnetotail. Nature 2001; 412:414-7. [PMID: 11473310 DOI: 10.1038/35086520] [Citation(s) in RCA: 411] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Magnetic reconnection is the process by which magnetic field lines of opposite polarity reconfigure to a lower-energy state, with the release of magnetic energy to the surroundings. Reconnection at the Earth's dayside magnetopause and in the magnetotail allows the solar wind into the magnetosphere. It begins in a small 'diffusion region', where a kink in the newly reconnected lines produces jets of plasma away from the region. Although plasma jets from reconnection have previously been reported, the physical processes that underlie jet formation have remained poorly understood because of the scarcity of in situ observations of the minuscule diffusion region. Theoretically, both resistive and collisionless processes can initiate reconnection, but which process dominates in the magnetosphere is still debated. Here we report the serendipitous encounter of the Wind spacecraft with an active reconnection diffusion region, in which are detected key processes predicted by models of collisionless reconnection. The data therefore demonstrate that collisionless reconnection occurs in the magnetotail.
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Affiliation(s)
- M Oieroset
- Space Sciences Laboratory, University of California, Berkeley, California 94720, USA.
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Pritchett PL. Geospace Environment Modeling magnetic reconnection challenge: Simulations with a full particle electromagnetic code. ACTA ACUST UNITED AC 2001. [DOI: 10.1029/1999ja001006] [Citation(s) in RCA: 300] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Shinohara I, Nagai T, Fujimoto M, Terasawa T, Mukai T, Tsuruda K, Yamamoto T. Low-frequency electromagnetic turbulence observed near the substorm onset site. ACTA ACUST UNITED AC 1998. [DOI: 10.1029/98ja01104] [Citation(s) in RCA: 101] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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