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Zhang LQ, Wang C, Baumjohann W, Wang RS, Wang JY, Burch JL, Khotyaintsev YV. First observation of fluid-like eddy-dominant bursty bulk flow turbulence in the Earth's tail plasma sheet. Sci Rep 2023; 13:19201. [PMID: 37932297 PMCID: PMC10628178 DOI: 10.1038/s41598-023-45867-w] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Accepted: 10/25/2023] [Indexed: 11/08/2023] Open
Abstract
Turbulence is a ubiquitous phenomenon in neutral and conductive fluids. According to classical theory, turbulence is a rotating flow containing vortices of different scales. Eddies play a fundamental role in the nonlinear cascade of kinetic energy at different scales in turbulent flow. In conductive fluids, the Alfvénic/kinetic Alfvénic wave (AW/KAW) is the new "cell" of magnetohydrodynamic (MHD) turbulence (frozen-in condition). Wave energy, which has equal kinetic and magnetic energy, is redistributed among multiple-scale Fourier modes and transferred from the large MHD scale to the small kinetic scale through the collision of counter-propagating Alfvénic wave packages propagating along the magnetic field line. Fluid-like eddy-dominant plasma flow turbulence has never been found in space since the launch of the first satellite in 1957. In this paper, we report the first observation of eddy-dominant turbulence within magnetic reconnection-generated fast flow in the Earth's tail plasma sheet by the Magnetospheric Multiscale Spacecraft (MMS). In eddy-dominant turbulent reconnection jet, ions dominate the flow field while electrons dominate current and magnetic fluctuations. Our findings shed new light on the nonlinear kinetic and magnetic energy cascade in MHD turbulence.
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Affiliation(s)
- L Q Zhang
- State Key Laboratory of Space Weather, National Space Science Center, Chinese Academy of Sciences, Beijing, 100080, China
| | - Chi Wang
- State Key Laboratory of Space Weather, National Space Science Center, Chinese Academy of Sciences, Beijing, 100080, China.
| | - W Baumjohann
- Space Research Institute, Austrian Academy of Sciences, 8042, Graz, Austria
| | - R S Wang
- CAS KCAS Key Laboratory of Geospace Environment, Department of Geophysics and Planetary Science, University of Science and Technology of China, Hefei, 230026, China
| | - J Y Wang
- Information Engineering College, Central University for Nationalities, Beijing, 100081, China
| | - James L Burch
- Southwest Research Institute San Antonio, San Antonio, TX, 78238, USA
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2
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Svenningsson I, Yordanova E, Cozzani G, Khotyaintsev YV, André M. Kinetic Generation of Whistler Waves in the Turbulent Magnetosheath. Geophys Res Lett 2022; 49:e2022GL099065. [PMID: 36247519 PMCID: PMC9541185 DOI: 10.1029/2022gl099065] [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] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Revised: 07/22/2022] [Accepted: 07/27/2022] [Indexed: 06/16/2023]
Abstract
The Earth's magnetosheath (MSH) is governed by numerous physical processes which shape the particle velocity distributions and contribute to the heating of the plasma. Among them are whistler waves which can interact with electrons. We investigate whistler waves detected in the quasi-parallel MSH by NASA's Magnetospheric Multiscale mission. We find that the whistler waves occur even in regions that are predicted stable to wave growth by electron temperature anisotropy. Whistlers are observed in ion-scale magnetic minima and are associated with electrons having butterfly-shaped pitch-angle distributions. We investigate in detail one example and, with the support of modeling by the linear numerical dispersion solver Waves in Homogeneous, Anisotropic, Multicomponent Plasmas, we demonstrate that the butterfly distribution is unstable to the observed whistler waves. We conclude that the observed waves are generated locally. The result emphasizes the importance of considering complete 3D particle distribution functions, and not only the temperature anisotropy, when studying plasma wave instabilities.
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Affiliation(s)
- I. Svenningsson
- Swedish Institute of Space PhysicsUppsalaSweden
- Department of Physics and AstronomyUppsala UniversityUppsalaSweden
| | | | - G. Cozzani
- Department of PhysicsUniversity of HelsinkiHelsinkiFinland
| | | | - M. André
- Swedish Institute of Space PhysicsUppsalaSweden
- Department of Physics and AstronomyUppsala UniversityUppsalaSweden
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3
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Alho M, Battarbee M, Pfau‐Kempf Y, Khotyaintsev YV, Nakamura R, Cozzani G, Ganse U, Turc L, Johlander A, Horaites K, Tarvus V, Zhou H, Grandin M, Dubart M, Papadakis K, Suni J, George H, Bussov M, Palmroth M. Electron Signatures of Reconnection in a Global eVlasiator Simulation. Geophys Res Lett 2022; 49:e2022GL098329. [PMID: 36249284 PMCID: PMC9541212 DOI: 10.1029/2022gl098329] [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: 02/15/2022] [Revised: 05/13/2022] [Accepted: 06/02/2022] [Indexed: 06/16/2023]
Abstract
Geospace plasma simulations have progressed toward more realistic descriptions of the solar wind-magnetosphere interaction from magnetohydrodynamic to hybrid ion-kinetic, such as the state-of-the-art Vlasiator model. Despite computational advances, electron scales have been out of reach in a global setting. eVlasiator, a novel Vlasiator submodule, shows for the first time how electromagnetic fields driven by global hybrid-ion kinetics influence electrons, resulting in kinetic signatures. We analyze simulated electron distributions associated with reconnection sites and compare them with Magnetospheric Multiscale (MMS) spacecraft observations. Comparison with MMS shows that key electron features, such as reconnection inflows, heated outflows, flat-top distributions, and bidirectional streaming, are in remarkable agreement. Thus, we show that many reconnection-related features can be reproduced despite strongly truncated electron physics and an ion-scale spatial resolution. Ion-scale dynamics and ion-driven magnetic fields are shown to be significantly responsible for the environment that produces electron dynamics observed by spacecraft in near-Earth plasmas.
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Affiliation(s)
- M. Alho
- Department of PhysicsUniversity of HelsinkiHelsinkiFinland
| | - M. Battarbee
- Department of PhysicsUniversity of HelsinkiHelsinkiFinland
| | - Y. Pfau‐Kempf
- Department of PhysicsUniversity of HelsinkiHelsinkiFinland
| | | | - R. Nakamura
- Space Research InstituteAustrian Academy of SciencesGrazAustria
| | - G. Cozzani
- Department of PhysicsUniversity of HelsinkiHelsinkiFinland
| | - U. Ganse
- Department of PhysicsUniversity of HelsinkiHelsinkiFinland
| | - L. Turc
- Department of PhysicsUniversity of HelsinkiHelsinkiFinland
| | - A. Johlander
- Department of PhysicsUniversity of HelsinkiHelsinkiFinland
- Swedish Institute of Space PhysicsUppsalaSweden
| | - K. Horaites
- Department of PhysicsUniversity of HelsinkiHelsinkiFinland
| | - V. Tarvus
- Department of PhysicsUniversity of HelsinkiHelsinkiFinland
| | - H. Zhou
- Department of PhysicsUniversity of HelsinkiHelsinkiFinland
| | - M. Grandin
- Department of PhysicsUniversity of HelsinkiHelsinkiFinland
| | - M. Dubart
- Department of PhysicsUniversity of HelsinkiHelsinkiFinland
| | - K. Papadakis
- Department of PhysicsUniversity of HelsinkiHelsinkiFinland
| | - J. Suni
- Department of PhysicsUniversity of HelsinkiHelsinkiFinland
| | - H. George
- Department of PhysicsUniversity of HelsinkiHelsinkiFinland
| | - M. Bussov
- Department of PhysicsUniversity of HelsinkiHelsinkiFinland
| | - M. Palmroth
- Department of PhysicsUniversity of HelsinkiHelsinkiFinland
- Finnish Meteorological InstituteHelsinkiFinland
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4
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Cozzani G, Khotyaintsev YV, Graham DB, Egedal J, André M, Vaivads A, Alexandrova A, Le Contel O, Nakamura R, Fuselier SA, Russell CT, Burch JL. Structure of a Perturbed Magnetic Reconnection Electron Diffusion Region in the Earth's Magnetotail. Phys Rev Lett 2021; 127:215101. [PMID: 34860109 DOI: 10.1103/physrevlett.127.215101] [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: 03/28/2021] [Revised: 09/22/2021] [Accepted: 10/07/2021] [Indexed: 06/13/2023]
Abstract
We report in situ observations of an electron diffusion region (EDR) and adjacent separatrix region in the Earth's magnetotail. We observe significant magnetic field oscillations near the lower hybrid frequency which propagate perpendicularly to the reconnection plane. We also find that the strong electron-scale gradients close to the EDR exhibit significant oscillations at a similar frequency. Such oscillations are not expected for a crossing of a steady 2D EDR, and can be explained by a complex motion of the reconnection plane induced by current sheet kinking propagating in the out-of-reconnection-plane direction. Thus, all three spatial dimensions have to be taken into account to explain the observed perturbed EDR crossing. These results shed light on the interplay between magnetic reconnection and current sheet drift instabilities in electron-scale current sheets and highlight the need for adopting a 3D description of the EDR, going beyond the two-dimensional and steady-state conception of reconnection.
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Affiliation(s)
- G Cozzani
- Swedish Institute of Space Physics, Uppsala 75121, Sweden
| | | | - D B Graham
- Swedish Institute of Space Physics, Uppsala 75121, Sweden
| | - J Egedal
- Department of Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - M André
- Swedish Institute of Space Physics, Uppsala 75121, Sweden
| | - A Vaivads
- Space and Plasma Physics, School of Electrical Engineering and Computer Science, KTH Royal Institute of Technology, Stockholm 11428, Sweden
| | - A Alexandrova
- Laboratoire de Physique des Plasmas, CNRS, Sorbonne Université, Université Paris-Saclay, Observatoire de Paris, École Polytechnique Institut Polytechnique de Paris, Palaiseau 91128, France
| | - O Le Contel
- Laboratoire de Physique des Plasmas, CNRS, Sorbonne Université, Université Paris-Saclay, Observatoire de Paris, École Polytechnique Institut Polytechnique de Paris, Palaiseau 91128, France
| | - R Nakamura
- Space Research Institute, Austrian Academy of Sciences, Graz 8042, Austria
| | - S A Fuselier
- Southwest Research Institute, San Antonio, Texas 78238, USA
- University of Texas at San Antonio, San Antonio, Texas 78249, USA
| | - C T Russell
- University of California, Los Angeles, California 90095, USA
| | - J L Burch
- Southwest Research Institute, San Antonio, Texas 78238, USA
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5
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Chen LJ, Wang S, Le Contel O, Rager A, Hesse M, Drake J, Dorelli J, Ng J, Bessho N, Graham D, Wilson LB, Moore T, Giles B, Paterson W, Lavraud B, Genestreti K, Nakamura R, Khotyaintsev YV, Ergun RE, Torbert RB, Burch J, Pollock C, Russell CT, Lindqvist PA, Avanov L. Lower-Hybrid Drift Waves Driving Electron Nongyrotropic Heating and Vortical Flows in a Magnetic Reconnection Layer. Phys Rev Lett 2020; 125:025103. [PMID: 32701350 DOI: 10.1103/physrevlett.125.025103] [Citation(s) in RCA: 1] [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: 10/10/2019] [Accepted: 06/11/2020] [Indexed: 06/11/2023]
Abstract
We report measurements of lower-hybrid drift waves driving electron heating and vortical flows in an electron-scale reconnection layer under a guide field. Electrons accelerated by the electrostatic potential of the waves exhibit perpendicular and nongyrotropic heating. The vortical flows generate magnetic field perturbations comparable to the guide field magnitude. The measurements reveal a new regime of electron-wave interaction and how this interaction modifies the electron dynamics in the reconnection layer.
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Affiliation(s)
- L-J Chen
- NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
| | - S Wang
- NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
- University of Maryland, College Park, Maryland 20747, USA
| | - O Le Contel
- CNRS/Ecole Polytechnique/Sorbonne Université/Univ. Paris Sud/Observatoire de Paris, Paris F91128, France
| | - A Rager
- NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
| | - M Hesse
- University of Bergen, Bergen 5020, Norway
| | - J Drake
- University of Maryland, College Park, Maryland 20747, USA
| | - J Dorelli
- NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
| | - J Ng
- NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
- University of Maryland, College Park, Maryland 20747, USA
| | - N Bessho
- NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
- University of Maryland, College Park, Maryland 20747, USA
| | - D Graham
- Swedish Institute of Space Physics, Uppsala SE-75121, Sweden
| | - Lynn B Wilson
- NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
| | - T Moore
- NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
| | - B Giles
- NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
| | - W Paterson
- NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
| | - B Lavraud
- Institut de Recherche en Astrophysique et Planétologie, Université de Toulouse (UPS), CNRS, CNES, Toulouse 31027 Cedex 4, France
| | - K Genestreti
- University of New Hampshire, Durham, New Hampshire 03824, USA
| | - R Nakamura
- Space Research Institute, Austrian Academy of Sciences, Graz A-8042, Austria
| | | | - R E Ergun
- University of Colorado, Boulder, Colorado 80305, USA
| | - R B Torbert
- University of New Hampshire, Durham, New Hampshire 03824, USA
| | - J Burch
- Southwest Research Institute, San Antonio, Texas 78238, USA
| | - C Pollock
- Denali Scientific, Healy, Alaska 99743, USA
| | - C T Russell
- University of California, Los Angeles, Los Angeles, California 90095, USA
| | - P-A Lindqvist
- KTH Royal Institute of Technology, Stockholm SE-11428, Sweden
| | - L Avanov
- NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
- University of Maryland, College Park, Maryland 20747, USA
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6
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Fu HS, Chen F, Chen ZZ, Xu Y, Wang Z, Liu YY, Liu CM, Khotyaintsev YV, Ergun RE, Giles BL, Burch JL. First Measurements of Electrons and Waves inside an Electrostatic Solitary Wave. Phys Rev Lett 2020; 124:095101. [PMID: 32202894 DOI: 10.1103/physrevlett.124.095101] [Citation(s) in RCA: 1] [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: 09/03/2019] [Revised: 11/08/2019] [Accepted: 02/14/2020] [Indexed: 06/10/2023]
Abstract
Electrostatic solitary wave (ESW)-a Debye-scale structure in space plasmas-was believed to accelerate electrons. However, such a belief is still unverified in spacecraft observations, because the ESW usually moves fast in spacecraft frame and its interior has never been directly explored. Here, we report the first measurements of an ESW's interior, by the Magnetospheric Multiscale mission located in a magnetotail reconnection jet. We find that this ESW has a parallel scale of 5λ_{De} (Debye length), a superslow speed (99 km/s) in spacecraft frame, a longtime duration (250 ms), and a potential drop eφ_{0}/kT_{e}∼5%. Inside the ESW, surprisingly, there is no electron acceleration, no clear change of electron distribution functions, but there exist strong electrostatic electron cyclotron waves. Our observations challenge the conventional belief that ESWs are efficient at particle acceleration.
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Affiliation(s)
- H S Fu
- School of Space and Environment, Beihang University, Beijing 100191, China
| | - F Chen
- School of Space and Environment, Beihang University, Beijing 100191, China
| | - Z Z Chen
- School of Space and Environment, Beihang University, Beijing 100191, China
| | - Y Xu
- School of Space and Environment, Beihang University, Beijing 100191, China
| | - Z Wang
- School of Space and Environment, Beihang University, Beijing 100191, China
| | - Y Y Liu
- School of Space and Environment, Beihang University, Beijing 100191, China
| | - C M Liu
- School of Space and Environment, Beihang University, Beijing 100191, China
| | | | - R E Ergun
- Department of Astrophysical and Planetary Sciences, University of Colorado Boulder, Boulder, Colorado 80303, USA
| | - B L Giles
- NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
| | - J L Burch
- Southwest Research Institute, San Antonio, Texas 78228, USA
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7
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Khotyaintsev YV, Graham DB, Steinvall K, Alm L, Vaivads A, Johlander A, Norgren C, Li W, Divin A, Fu HS, Hwang KJ, Burch JL, Ahmadi N, Le Contel O, Gershman DJ, Russell CT, Torbert RB. Electron Heating by Debye-Scale Turbulence in Guide-Field Reconnection. Phys Rev Lett 2020; 124:045101. [PMID: 32058767 DOI: 10.1103/physrevlett.124.045101] [Citation(s) in RCA: 2] [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: 08/05/2019] [Revised: 11/22/2019] [Indexed: 06/10/2023]
Abstract
We report electrostatic Debye-scale turbulence developing within the diffusion region of asymmetric magnetopause reconnection with a moderate guide field using observations by the Magnetospheric Multiscale mission. We show that Buneman waves and beam modes cause efficient and fast thermalization of the reconnection electron jet by irreversible phase mixing, during which the jet kinetic energy is transferred into thermal energy. Our results show that the reconnection diffusion region in the presence of a moderate guide field is highly turbulent, and that electrostatic turbulence plays an important role in electron heating.
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Affiliation(s)
| | - D B Graham
- Swedish Institute of Space Physics, Uppsala 75121, Sweden
| | - K Steinvall
- Swedish Institute of Space Physics, Uppsala 75121, Sweden
| | - L Alm
- Swedish Institute of Space Physics, Uppsala 75121, Sweden
| | - A Vaivads
- Department of Space and Plasma Physics, School of Electrical Engineering and Computer Science, KTH Royal Institute of Technology, Stockholm 11428, Sweden
| | - A Johlander
- Department of Physics, University of Helsinki, Helsinki 00014, Finland
| | - C Norgren
- University of Bergen, Bergen 5007, Norway
| | - W Li
- State Key Laboratory of Space Weather, National Space Science Center, Chinese Academy of Sciences, Beijing 100190, China
| | - A Divin
- Earth Physics Department, St. Petersburg State University, St. Petersburg 198504, Russia
| | - H S Fu
- School of Space and Environment, Beihang University, Beijing 100083, China
| | - K-J Hwang
- Southwest Research Institute, San Antonio, Texas 78228, USA
| | - J L Burch
- Southwest Research Institute, San Antonio, Texas 78228, USA
| | - N Ahmadi
- Laboratory of Atmospheric and Space Physics, University of Colorado, Boulder, Colorado 80303, USA
| | - O Le Contel
- Laboratoire de Physique des Plasmas, CNRS, Ecole Polytechnique, Sorbonne Université, Université Paris-Sud, and Observatoire de Paris, Paris, F-75252 Paris Cedex 05, France
| | - D J Gershman
- NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
| | - C T Russell
- University of California, Los Angeles, California 90095, USA
| | - R B Torbert
- University of New Hampshire, Durham, New Hampshire 03824, USA
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8
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Chen LJ, Wang S, Wilson LB, Schwartz S, Bessho N, Moore T, Gershman D, Giles B, Malaspina D, Wilder FD, Ergun RE, Hesse M, Lai H, Russell C, Strangeway R, Torbert RB, F-Vinas A, Burch J, Lee S, Pollock C, Dorelli J, Paterson W, Ahmadi N, Goodrich K, Lavraud B, Le Contel O, Khotyaintsev YV, Lindqvist PA, Boardsen S, Wei H, Le A, Avanov L. Electron Bulk Acceleration and Thermalization at Earth's Quasiperpendicular Bow Shock. Phys Rev Lett 2018; 120:225101. [PMID: 29906189 DOI: 10.1103/physrevlett.120.225101] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Revised: 03/30/2018] [Indexed: 06/08/2023]
Abstract
Electron heating at Earth's quasiperpendicular bow shock has been surmised to be due to the combined effects of a quasistatic electric potential and scattering through wave-particle interaction. Here we report the observation of electron distribution functions indicating a new electron heating process occurring at the leading edge of the shock front. Incident solar wind electrons are accelerated parallel to the magnetic field toward downstream, reaching an electron-ion relative drift speed exceeding the electron thermal speed. The bulk acceleration is associated with an electric field pulse embedded in a whistler-mode wave. The high electron-ion relative drift is relaxed primarily through a nonlinear current-driven instability. The relaxed distributions contain a beam traveling toward the shock as a remnant of the accelerated electrons. Similar distribution functions prevail throughout the shock transition layer, suggesting that the observed acceleration and thermalization is essential to the cross-shock electron heating.
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Affiliation(s)
- L-J Chen
- NASA, Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
- Department of Astronomy, University of Maryland, College Park, Maryland 20747, USA
| | - S Wang
- NASA, Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
- Department of Astronomy, University of Maryland, College Park, Maryland 20747, USA
| | - L B Wilson
- NASA, Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
| | - S Schwartz
- Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, Colorado 80305, USA
| | - N Bessho
- NASA, Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
- Department of Astronomy, University of Maryland, College Park, Maryland 20747, USA
| | - T Moore
- NASA, Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
| | - D Gershman
- NASA, Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
| | - B Giles
- NASA, Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
| | - D Malaspina
- Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, Colorado 80305, USA
| | - F D Wilder
- Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, Colorado 80305, USA
| | - R E Ergun
- Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, Colorado 80305, USA
| | - M Hesse
- University of Bergen, Bergen 5020, Norway
| | - H Lai
- University of California, Los Angeles, Los Angeles, California 90095, USA
| | - C Russell
- University of California, Los Angeles, Los Angeles, California 90095, USA
| | - R Strangeway
- University of California, Los Angeles, Los Angeles, California 90095, USA
| | - R B Torbert
- Southwest Research Institute, San Antonio, Texas 78238, USA
| | - A F-Vinas
- NASA, Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
| | - J Burch
- Southwest Research Institute, San Antonio, Texas 78238, USA
| | - S Lee
- NASA, Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
| | - C Pollock
- Denali Scientific, Healy, Alaska 99743, USA
| | - J Dorelli
- NASA, Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
| | - W Paterson
- NASA, Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
| | - N Ahmadi
- Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, Colorado 80305, USA
| | - K Goodrich
- Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, Colorado 80305, USA
| | - B Lavraud
- Institut de Recherche en Astrophysique et Planétologie, Université de Toulouse (UPS), CNRS, CNES, Toulouse, 31028 Cedex 4, France
| | - O Le Contel
- Laboratoire de Physique des Plasmas (UMR7648), CNRS/Ecole Polytechnique/Sorbonne Université/Univ. Paris Sud/Observatoire de Paris, Paris, F91128 Palaiseau Cedex, France
| | | | - P-A Lindqvist
- KTH Royal Institute of Technology, Stockholm SE-11428, Sweden
| | - S Boardsen
- NASA, Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
- Department of Astronomy, University of Maryland, College Park, Maryland 20747, USA
| | - H Wei
- University of California, Los Angeles, Los Angeles, California 90095, USA
| | - A Le
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - L Avanov
- NASA, Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
- Department of Astronomy, University of Maryland, College Park, Maryland 20747, USA
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9
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Zhou M, Berchem J, Walker RJ, El-Alaoui M, Deng X, Cazzola E, Lapenta G, Goldstein ML, Paterson WR, Pang Y, Ergun RE, Lavraud B, Liang H, Russell CT, Strangeway RJ, Zhao C, Giles BL, Pollock CJ, Lindqvist PA, Marklund G, Wilder FD, Khotyaintsev YV, Torbert RB, Burch JL. Coalescence of Macroscopic Flux Ropes at the Subsolar Magnetopause: Magnetospheric Multiscale Observations. Phys Rev Lett 2017; 119:055101. [PMID: 28949734 DOI: 10.1103/physrevlett.119.055101] [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: 01/24/2017] [Indexed: 06/07/2023]
Abstract
We report unambiguous in situ observation of the coalescence of macroscopic flux ropes by the magnetospheric multiscale (MMS) mission. Two coalescing flux ropes with sizes of ∼1 R_{E} were identified at the subsolar magnetopause by the occurrence of an asymmetric quadrupolar signature in the normal component of the magnetic field measured by the MMS spacecraft. An electron diffusion region (EDR) with a width of four local electron inertial lengths was embedded within the merging current sheet. The EDR was characterized by an intense parallel electric field, significant energy dissipation, and suprathermal electrons. Although the electrons were organized by a large guide field, the small observed electron pressure nongyrotropy may be sufficient to support a significant fraction of the parallel electric field within the EDR. Since the flux ropes are observed in the exhaust region, we suggest that secondary EDRs are formed further downstream of the primary reconnection line between the magnetosheath and magnetospheric fields.
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Affiliation(s)
- M Zhou
- Department of Physics and Astronomy, UCLA, Los Angeles 90095, California, USA
| | - J Berchem
- Department of Physics and Astronomy, UCLA, Los Angeles 90095, California, USA
| | - R J Walker
- Department of Earth, Planetary, and Space Sciences, UCLA, Los Angeles 90095, California, USA
| | - M El-Alaoui
- Department of Physics and Astronomy, UCLA, Los Angeles 90095, California, USA
| | - X Deng
- Nanchang University, Nanchang 330031, People's Republic of China
| | - E Cazzola
- Centre for Plasma Astrophysics, Department of Mathematics, Katholieke Universiteit, Leuven 3001, Belgium
| | - G Lapenta
- Centre for Plasma Astrophysics, Department of Mathematics, Katholieke Universiteit, Leuven 3001, Belgium
| | - M L Goldstein
- NASA, Goddard Space Flight Center, Greenbelt 20771, Maryland, USA
- Space Science Institute, Boulder 80301, Colorado, USA
| | - W R Paterson
- NASA, Goddard Space Flight Center, Greenbelt 20771, Maryland, USA
| | - Y Pang
- Nanchang University, Nanchang 330031, People's Republic of China
| | - R E Ergun
- University of Colorado LASP, Boulder 80303, Colorado, USA
| | - B Lavraud
- Institut de Recherche en Astrophysique et Planétologie, Université de Toulouse, CNRS, UPS, CNES, Toulouse 31028, France
| | - H Liang
- Department of Physics and Astronomy, UCLA, Los Angeles 90095, California, USA
| | - C T Russell
- Department of Earth, Planetary, and Space Sciences, UCLA, Los Angeles 90095, California, USA
| | - R J Strangeway
- Department of Earth, Planetary, and Space Sciences, UCLA, Los Angeles 90095, California, USA
| | - C Zhao
- Department of Earth, Planetary, and Space Sciences, UCLA, Los Angeles 90095, California, USA
| | - B L Giles
- NASA, Goddard Space Flight Center, Greenbelt 20771, Maryland, USA
| | - C J Pollock
- NASA, Goddard Space Flight Center, Greenbelt 20771, Maryland, USA
| | - P-A Lindqvist
- Royal Institute of Technology, Stockholm SE-11428, Sweden
| | - G Marklund
- Royal Institute of Technology, Stockholm SE-11428, Sweden
| | - F D Wilder
- University of Colorado LASP, Boulder 80303, Colorado, USA
| | | | - R B Torbert
- University of New Hampshire, Durham, New Hampshire 03824, USA
| | - J L Burch
- Southwest Research Institute, San Antonio Texas 78238, USA
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10
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Graham DB, Khotyaintsev YV, Vaivads A, Norgren C, André M, Webster JM, Burch JL, Lindqvist PA, Ergun RE, Torbert RB, Paterson WR, Gershman DJ, Giles BL, Magnes W, Russell CT. Instability of Agyrotropic Electron Beams near the Electron Diffusion Region. Phys Rev Lett 2017; 119:025101. [PMID: 28753352 DOI: 10.1103/physrevlett.119.025101] [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: 12/03/2016] [Indexed: 06/07/2023]
Abstract
During a magnetopause crossing the Magnetospheric Multiscale spacecraft encountered an electron diffusion region (EDR) of asymmetric reconnection. The EDR is characterized by agyrotropic beam and crescent electron distributions perpendicular to the magnetic field. Intense upper-hybrid (UH) waves are found at the boundary between the EDR and magnetosheath inflow region. The UH waves are generated by the agyrotropic electron beams. The UH waves are sufficiently large to contribute to electron diffusion and scattering, and are a potential source of radio emission near the EDR. These results provide observational evidence of wave-particle interactions at an EDR, and suggest that waves play an important role in determining the electron dynamics.
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Affiliation(s)
- D B Graham
- Swedish Institute of Space Physics, Uppsala SE-75121, Sweden
| | | | - A Vaivads
- Swedish Institute of Space Physics, Uppsala SE-75121, Sweden
| | - C Norgren
- Swedish Institute of Space Physics, Uppsala SE-75121, Sweden
- Department of Physics and Astronomy, Uppsala University, Uppsala SE-75121, Sweden
| | - M André
- Swedish Institute of Space Physics, Uppsala SE-75121, Sweden
| | - J M Webster
- Department of Physics and Astronomy, Rice University, Houston, Texas 77005, USA
| | - J L Burch
- Southwest Research Institute, San Antonio, Texas 78238, USA
| | - P-A Lindqvist
- Space and Plasma Physics, School of Electrical Engineering, KTH Royal Institute of Technology, Stockholm SE-11428, Sweden
| | - R E Ergun
- Laboratory of Atmospheric and Space Physics, University of Colorado, Boulder, Colorado 80303, USA
| | - R B Torbert
- Space Science Center, University of New Hampshire, Durham, New Hampshire 03824, USA
| | - W R Paterson
- NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
| | - D J Gershman
- NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
- Department of Astronomy, University of Maryland, College Park, Maryland 20742, USA
| | - B L Giles
- NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
| | - W Magnes
- Space Research Institute, Austrian Academy of Sciences, Graz 8042, Austria
| | - C T Russell
- Department of Earth and Space Sciences, University of California, Los Angeles, California 90095, USA
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11
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Johlander A, Schwartz SJ, Vaivads A, Khotyaintsev YV, Gingell I, Peng IB, Markidis S, Lindqvist PA, Ergun RE, Marklund GT, Plaschke F, Magnes W, Strangeway RJ, Russell CT, Wei H, Torbert RB, Paterson WR, Gershman DJ, Dorelli JC, Avanov LA, Lavraud B, Saito Y, Giles BL, Pollock CJ, Burch JL. Rippled Quasiperpendicular Shock Observed by the Magnetospheric Multiscale Spacecraft. Phys Rev Lett 2016; 117:165101. [PMID: 27792387 DOI: 10.1103/physrevlett.117.165101] [Citation(s) in RCA: 4] [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: 06/10/2016] [Indexed: 06/06/2023]
Abstract
Collisionless shock nonstationarity arising from microscale physics influences shock structure and particle acceleration mechanisms. Nonstationarity has been difficult to quantify due to the small spatial and temporal scales. We use the closely spaced (subgyroscale), high-time-resolution measurements from one rapid crossing of Earth's quasiperpendicular bow shock by the Magnetospheric Multiscale (MMS) spacecraft to compare competing nonstationarity processes. Using MMS's high-cadence kinetic plasma measurements, we show that the shock exhibits nonstationarity in the form of ripples.
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Affiliation(s)
- A Johlander
- Swedish Institute of Space Physics, Uppsala 75121, Sweden
- Department of Physics and Astronomy, Uppsala University, Uppsala 75120, Sweden
| | - S J Schwartz
- Blackett Laboratory, Imperial College London, London SW7 2AZ, United Kingdom
- Laboratory of Atmospheric and Space Physics, University of Colorado, Boulder, Colorado 80303, USA
| | - A Vaivads
- Swedish Institute of Space Physics, Uppsala 75121, Sweden
| | | | - I Gingell
- Blackett Laboratory, Imperial College London, London SW7 2AZ, United Kingdom
| | - I B Peng
- KTH Royal Institute of Technology, Stockholm 11428, Sweden
| | - S Markidis
- KTH Royal Institute of Technology, Stockholm 11428, Sweden
| | - P-A Lindqvist
- KTH Royal Institute of Technology, Stockholm 11428, Sweden
| | - R E Ergun
- Laboratory of Atmospheric and Space Physics, University of Colorado, Boulder, Colorado 80303, USA
| | - G T Marklund
- KTH Royal Institute of Technology, Stockholm 11428, Sweden
| | - F Plaschke
- Space Research Institute, Austrian Academy of Sciences, Graz 8042, Austria
| | - W Magnes
- Space Research Institute, Austrian Academy of Sciences, Graz 8042, Austria
| | - R J Strangeway
- University of California, Los Angeles, California 90095, USA
| | - C T Russell
- University of California, Los Angeles, California 90095, USA
| | - H Wei
- University of California, Los Angeles, California 90095, USA
| | - R B Torbert
- University of New Hampshire, Durham, New Hampshire 03824, USA
| | - W R Paterson
- NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
| | - D J Gershman
- NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
- University of Maryland, College Park, Maryland 20742, USA
| | - J C Dorelli
- NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
| | - L A Avanov
- NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
| | - B Lavraud
- Institut de Recherche en Astrophysique et Planétologie, Université de Toulouse, Toulouse 31028, France
- Centre National de la Recherche Scientifique, UMR 5277, Toulouse 31400, France
| | - Y Saito
- Institute of Space and Astronautical Science, JAXA, Sagamihara 2525210, Japan
| | - B L Giles
- NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
| | - C J Pollock
- NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
| | - J L Burch
- Southwest Research Institute, San Antonio, Texas 78238, USA
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12
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Burch JL, Torbert RB, Phan TD, Chen LJ, Moore TE, Ergun RE, Eastwood JP, Gershman DJ, Cassak PA, Argall MR, Wang S, Hesse M, Pollock CJ, Giles BL, Nakamura R, Mauk BH, Fuselier SA, Russell CT, Strangeway RJ, Drake JF, Shay MA, Khotyaintsev YV, Lindqvist PA, Marklund G, Wilder FD, Young DT, Torkar K, Goldstein J, Dorelli JC, Avanov LA, Oka M, Baker DN, Jaynes AN, Goodrich KA, Cohen IJ, Turner DL, Fennell JF, Blake JB, Clemmons J, Goldman M, Newman D, Petrinec SM, Trattner KJ, Lavraud B, Reiff PH, Baumjohann W, Magnes W, Steller M, Lewis W, Saito Y, Coffey V, Chandler M. Electron-scale measurements of magnetic reconnection in space. Science 2016; 352:aaf2939. [PMID: 27174677 DOI: 10.1126/science.aaf2939] [Citation(s) in RCA: 438] [Impact Index Per Article: 54.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Accepted: 05/03/2016] [Indexed: 11/02/2022]
Abstract
Magnetic reconnection is a fundamental physical process in plasmas whereby stored magnetic energy is converted into heat and kinetic energy of charged particles. Reconnection occurs in many astrophysical plasma environments and in laboratory plasmas. Using measurements with very high time resolution, NASA's Magnetospheric Multiscale (MMS) mission has found direct evidence for electron demagnetization and acceleration at sites along the sunward boundary of Earth's magnetosphere where the interplanetary magnetic field reconnects with the terrestrial magnetic field. We have (i) observed the conversion of magnetic energy to particle energy; (ii) measured the electric field and current, which together cause the dissipation of magnetic energy; and (iii) identified the electron population that carries the current as a result of demagnetization and acceleration within the reconnection diffusion/dissipation region.
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Affiliation(s)
- J L Burch
- Southwest Research Institute, San Antonio, TX, USA.
| | - R B Torbert
- Southwest Research Institute, San Antonio, TX, USA. University of New Hampshire, Durham, NH, USA
| | - T D Phan
- University of California, Berkeley, CA, USA
| | - L-J Chen
- University of Maryland, College Park, MD, USA
| | - T E Moore
- NASA, Goddard Space Flight Center, Greenbelt, MD, USA
| | - R E Ergun
- University of Colorado LASP, Boulder, CO, USA
| | - J P Eastwood
- Blackett Laboratory, Imperial College London, London, UK
| | - D J Gershman
- NASA, Goddard Space Flight Center, Greenbelt, MD, USA
| | - P A Cassak
- West Virginia University, Morgantown, WV, USA
| | - M R Argall
- University of New Hampshire, Durham, NH, USA
| | - S Wang
- University of Maryland, College Park, MD, USA
| | - M Hesse
- NASA, Goddard Space Flight Center, Greenbelt, MD, USA
| | - C J Pollock
- NASA, Goddard Space Flight Center, Greenbelt, MD, USA
| | - B L Giles
- NASA, Goddard Space Flight Center, Greenbelt, MD, USA
| | - R Nakamura
- Space Research Institute, Austrian Academy of Sciences, Graz, Austria
| | - B H Mauk
- Johns Hopkins University Applied Physics Laboratory, Laurel, MD, USA
| | - S A Fuselier
- Southwest Research Institute, San Antonio, TX, USA
| | - C T Russell
- University of California, Los Angeles, CA, USA
| | | | - J F Drake
- University of Maryland, College Park, MD, USA
| | - M A Shay
- University of Delaware, Newark, DE, USA
| | | | | | - G Marklund
- Royal Institute of Technology, Stockholm, Sweden
| | - F D Wilder
- University of Colorado LASP, Boulder, CO, USA
| | - D T Young
- Southwest Research Institute, San Antonio, TX, USA
| | - K Torkar
- Space Research Institute, Austrian Academy of Sciences, Graz, Austria
| | - J Goldstein
- Southwest Research Institute, San Antonio, TX, USA
| | - J C Dorelli
- NASA, Goddard Space Flight Center, Greenbelt, MD, USA
| | - L A Avanov
- NASA, Goddard Space Flight Center, Greenbelt, MD, USA
| | - M Oka
- University of California, Berkeley, CA, USA
| | - D N Baker
- University of Colorado LASP, Boulder, CO, USA
| | - A N Jaynes
- University of Colorado LASP, Boulder, CO, USA
| | | | - I J Cohen
- Johns Hopkins University Applied Physics Laboratory, Laurel, MD, USA
| | - D L Turner
- Aerospace Corporation, El Segundo, CA, USA
| | | | - J B Blake
- Aerospace Corporation, El Segundo, CA, USA
| | - J Clemmons
- Aerospace Corporation, El Segundo, CA, USA
| | - M Goldman
- University of Colorado, Boulder, CO, USA
| | - D Newman
- University of Colorado, Boulder, CO, USA
| | - S M Petrinec
- Lockheed Martin Advanced Technology Center, Palo Alto, CA, USA
| | | | - B Lavraud
- Institut de Recherche en Astrophysique et Planétologie, Toulouse, France
| | - P H Reiff
- Department of Physics and Astronomy, Rice University, Houston, TX, USA
| | - W Baumjohann
- Space Research Institute, Austrian Academy of Sciences, Graz, Austria
| | - W Magnes
- Space Research Institute, Austrian Academy of Sciences, Graz, Austria
| | - M Steller
- Space Research Institute, Austrian Academy of Sciences, Graz, Austria
| | - W Lewis
- Southwest Research Institute, San Antonio, TX, USA
| | - Y Saito
- Institute for Space and Astronautical Sciences, Sagamihara, Japan
| | - V Coffey
- NASA, Marshall Space Flight Center, Huntsville, AL, USA
| | - M Chandler
- NASA, Marshall Space Flight Center, Huntsville, AL, USA
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13
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Chasapis A, Retinò A, Sahraoui F, Vaivads A, Khotyaintsev YV, Sundkvist D, Greco A, Sorriso-Valvo L, Canu P. THIN CURRENT SHEETS AND ASSOCIATED ELECTRON HEATING IN TURBULENT SPACE PLASMA. ACTA ACUST UNITED AC 2015. [DOI: 10.1088/2041-8205/804/1/l1] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [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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14
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Affiliation(s)
- F Sahraoui
- Laboratoire de Physique des Plasmas, CNRS-Ecole Polytechnique, Palaiseau 91120, France
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15
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Khotyaintsev YV, Cully CM, Vaivads A, André M, Owen CJ. Plasma jet braking: energy dissipation and nonadiabatic electrons. Phys Rev Lett 2011; 106:165001. [PMID: 21599373 DOI: 10.1103/physrevlett.106.165001] [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: 12/08/2010] [Indexed: 05/30/2023]
Abstract
We report in situ observations by the Cluster spacecraft of wave-particle interactions in a magnetic flux pileup region created by a magnetic reconnection outflow jet in Earth's magnetotail. Two distinct regions of wave activity are identified: lower-hybrid drift waves at the front edge and whistler-mode waves inside the pileup region. The whistler-mode waves are locally generated by the electron temperature anisotropy, and provide evidence for ongoing betatron energization caused by magnetic flux pileup. The whistler-mode waves cause fast pitch-angle scattering of electrons and isotropization of the electron distribution, thus making the flow braking process nonadiabatic. The waves strongly affect the electron dynamics and thus play an important role in the energy conversion chain during plasma jet braking.
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16
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Khotyaintsev YV, Vaivads A, André M, Fujimoto M, Retinò A, Owen CJ. Observations of slow electron holes at a magnetic reconnection site. Phys Rev Lett 2010; 105:165002. [PMID: 21230981 DOI: 10.1103/physrevlett.105.165002] [Citation(s) in RCA: 3] [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: 07/09/2010] [Indexed: 05/30/2023]
Abstract
We report in situ observations of high-frequency electrostatic waves in the vicinity of a reconnection site in the Earth's magnetotail. Two different types of waves are observed inside an ion-scale magnetic flux rope embedded in a reconnecting current sheet. Electron holes (weak double layers) produced by the Buneman instability are observed in the density minimum in the center of the flux rope. Higher frequency broadband electrostatic waves with frequencies extending up to f(pe) are driven by the electron beam and are observed in the denser part of the rope. Our observations demonstrate multiscale coupling during the reconnection: Electron-scale physics is induced by the dynamics of an ion-scale flux rope embedded in a yet larger-scale magnetic reconnection process.
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17
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Kiyani KH, Chapman SC, Khotyaintsev YV, Dunlop MW, Sahraoui F. Global scale-invariant dissipation in collisionless plasma turbulence. Phys Rev Lett 2009; 103:075006. [PMID: 19792654 DOI: 10.1103/physrevlett.103.075006] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2009] [Indexed: 05/28/2023]
Abstract
A higher-order multiscale analysis of the dissipation range of collisionless plasma turbulence is presented using in situ high-frequency magnetic field measurements from the Cluster spacecraft in a stationary interval of fast ambient solar wind. The observations, spanning five decades in temporal scales, show a crossover from multifractal intermittent turbulence in the inertial range to non-Gaussian monoscaling in the dissipation range. This presents a strong observational constraint on theories of dissipation mechanisms in turbulent collisionless plasmas.
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Affiliation(s)
- K H Kiyani
- Centre for Fusion, Space and Astrophysics; University of Warwick, Coventry CV4 7AL, United Kingdom.
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18
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Sahraoui F, Goldstein ML, Robert P, Khotyaintsev YV. Evidence of a cascade and dissipation of solar-wind turbulence at the electron gyroscale. Phys Rev Lett 2009; 102:231102. [PMID: 19658919 DOI: 10.1103/physrevlett.102.231102] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2009] [Indexed: 05/28/2023]
Abstract
We report the first direct determination of the dissipation range of magnetofluid turbulence in the solar wind at the electron scales. Combining high resolution magnetic and electric field data of the Cluster spacecraft, we computed the spectrum of turbulence and found two distinct breakpoints in the magnetic spectrum at 0.4 and 35 Hz, which correspond, respectively, to the Doppler-shifted proton and electron gyroscales, f(rho p) and f(rho e). Below f(rho p), the spectrum follows a Kolmogorov scaling f (-1.62), typical of spectra observed at 1 AU. Above f (rho p), a second inertial range is formed with a scaling f;{-2.3} down to f (rho e). Above f (rho e), the spectrum has a steeper power law approximately f (-4.1) down to the noise level of the instrument. We interpret this as the dissipation range and show a remarkable agreement with theoretical predictions of a quasi-two-dimensional cascade into Kinetic Alfvén Waves (KAW).
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Affiliation(s)
- F Sahraoui
- NASA Goddard Space Flight Center, Code 673, Greenbelt, Maryland 20771, USA.
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19
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Khotyaintsev YV, Vaivads A, Retinò A, André M, Owen CJ, Nilsson H. Formation of inner structure of a reconnection separatrix region. Phys Rev Lett 2006; 97:205003. [PMID: 17155688 DOI: 10.1103/physrevlett.97.205003] [Citation(s) in RCA: 3] [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: 04/04/2006] [Indexed: 05/12/2023]
Abstract
We present multipoint spacecraft observations at the dayside magnetopause of a magnetic reconnection separatrix region. This region separates two plasmas with significantly different temperatures and densities, at a large distance from the X line. We identify which terms in the generalized Ohm's law balance the observed electric field throughout the separatrix region. The electric field inside a thin approximately c/omega pi Hall layer is balanced by the j x B/ne term while other terms dominate elsewhere. On the low density side of the region we observe a density cavity which forms due to the escape of magnetospheric electrons along the newly opened field lines. The perpendicular electric field inside the cavity constitutes a potential jump of several kV. The observed potential jump and field aligned currents can be responsible for strong aurora.
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Affiliation(s)
- Yu V Khotyaintsev
- Swedish Institute of Space Physics, Box 537, SE-751 21 Uppsala, Sweden
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