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Shi P, Srivastav P, Barbhuiya MH, Cassak PA, Scime EE, Swisdak M. Laboratory Observations of Electron Heating and Non-Maxwellian Distributions at the Kinetic Scale during Electron-Only Magnetic Reconnection. PHYSICAL REVIEW LETTERS 2022; 128:025002. [PMID: 35089758 DOI: 10.1103/physrevlett.128.025002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Accepted: 12/08/2021] [Indexed: 06/14/2023]
Abstract
Non-Maxwellian electron velocity distribution functions composed of a warm bulk population and a cold beam are directly measured during electron-only reconnection with a strong out-of-plane (guide) magnetic field in a laboratory plasma. Electron heating is localized to the separatrix, and the electron temperature increases continuously along the separatrix. The measured gain in enthalpy flux is 70% of the incoming Poynting flux. The electron beams are oppositely directed on either side of the X point, and their velocities are comparable to, and scale with, the electron Alfvén speed. Particle-in-cell simulations are consistent with the measurements. The experimental results are consistent with, and go beyond, recent observations in the magnetosheath.
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Affiliation(s)
- Peiyun Shi
- Department of Physics and Astronomy and the Center for KINETIC Plasma Physics, West Virginia University, Morgantown, West Virginia 26506, USA
| | - Prabhakar Srivastav
- Department of Physics and Astronomy and the Center for KINETIC Plasma Physics, West Virginia University, Morgantown, West Virginia 26506, USA
| | - M Hasan Barbhuiya
- Department of Physics and Astronomy and the Center for KINETIC Plasma Physics, West Virginia University, Morgantown, West Virginia 26506, USA
| | - Paul A Cassak
- Department of Physics and Astronomy and the Center for KINETIC Plasma Physics, West Virginia University, Morgantown, West Virginia 26506, USA
| | - Earl E Scime
- Department of Physics and Astronomy and the Center for KINETIC Plasma Physics, West Virginia University, Morgantown, West Virginia 26506, USA
| | - M Swisdak
- Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, Maryland 20742, USA
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2
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Shi P, Srivastav P, Beatty C, Nirwan RS, Scime EE. Incoherent Thomson scattering system for PHAse space MApping (PHASMA) experiment. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2021; 92:033102. [PMID: 33820086 DOI: 10.1063/5.0040606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Accepted: 02/18/2021] [Indexed: 06/12/2023]
Abstract
A new incoherent Thomson scattering system measures the evolution of electron velocity distribution functions perpendicular and parallel to the ambient magnetic field during kinking of a single flux rope and merging of two flux ropes through magnetic reconnection. The Thomson scattering system provides sub-millimeter spatial resolution, sufficient to diagnose the several millimeters sized magnetic reconnection electron diffusion region in the PHAse Space MAppgin experiment. Due to the relatively modest plasma density ∼1019 m-3 and electron temperature ∼1 eV, stray light suppression is critical for these measurements. Two volume Bragg gratings are used in series as a notch filter with a spectral bandwidth <0.1 nm in the collection branch. A CCD with a Gen III intensifier with peak quantum efficiency >47% is used as the detector in a 1.3 m spectrometer. Preliminary results of gun plasma electron temperature will be reported and compared with measurements obtained from a triple Langmuir probe.
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Affiliation(s)
- Peiyun Shi
- Department of Physics and Astronomy, West Virginia University and Center for KINETIC Plasma Physics, Morgantown, West Virginia 26506, USA
| | - Prabhakar Srivastav
- Department of Physics and Astronomy, West Virginia University and Center for KINETIC Plasma Physics, Morgantown, West Virginia 26506, USA
| | - Cuyler Beatty
- Department of Physics and Astronomy, West Virginia University and Center for KINETIC Plasma Physics, Morgantown, West Virginia 26506, USA
| | - Ripudaman Singh Nirwan
- Department of Physics and Astronomy, West Virginia University and Center for KINETIC Plasma Physics, Morgantown, West Virginia 26506, USA
| | - Earl E Scime
- Department of Physics and Astronomy, West Virginia University and Center for KINETIC Plasma Physics, Morgantown, West Virginia 26506, USA
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3
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Chian ACL, Silva SSA, Rempel EL, Rubio LRB, Gošić M, Kusano K, Park SH. Lagrangian chaotic saddles and objective vortices in solar plasmas. Phys Rev E 2021; 102:060201. [PMID: 33466044 DOI: 10.1103/physreve.102.060201] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Accepted: 10/18/2020] [Indexed: 11/06/2022]
Abstract
We report observational evidence of Lagrangian chaotic saddles in plasmas, given by the intersections of finite-time unstable and stable manifolds, using an ≈22h sequence of spacecraft images of the horizontal velocity field of solar photosphere. A set of 29 persistent objective vortices with lifetimes varying from 28.5 to 298.3 min are detected by computing the Lagrangian averaged vorticity deviation. The unstable manifold of the Lagrangian chaotic saddles computed for ≈11h exhibits twisted folding motions indicative of recurring vortices in a magnetic mixed-polarity region. We show that the persistent objective vortices are formed in the gap regions of Lagrangian chaotic saddles at supergranular junctions.
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Affiliation(s)
- Abraham C-L Chian
- Institute for Space-Earth Environmental Research (ISEE), Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan.,School of Mathematical Sciences, University of Adelaide, Adelaide, SA 5005, Australia.,National Institute for Space Research (INPE), P.O. Box 515, São José dos Campos, São Paulo 12227-010, Brazil
| | - Suzana S A Silva
- Institute of Aeronautical Technology (ITA), São José dos Campos, São Paulo 12228-900, Brazil
| | - Erico L Rempel
- National Institute for Space Research (INPE), P.O. Box 515, São José dos Campos, São Paulo 12227-010, Brazil.,Institute of Aeronautical Technology (ITA), São José dos Campos, São Paulo 12228-900, Brazil
| | - Luis R Bellot Rubio
- Instituto de Astrofísica de Andalucía (CSIC), Apartado de Correos 3004, E-18080 Granada, Spain
| | - Milan Gošić
- Lockheed Martin Solar and Astrophysics Laboratory, Palo Alto, California 94304, USA.,Bay Area Environmental Research Institute, Moffett Field, California 94035, USA
| | - Kanya Kusano
- Institute for Space-Earth Environmental Research (ISEE), Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan
| | - Sung-Hong Park
- Institute for Space-Earth Environmental Research (ISEE), Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan
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4
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Gekelman W, DeHaas T, Prior C, Yeates A. Using topology to locate the position where fully three-dimensional reconnection occurs. SN APPLIED SCIENCES 2020. [DOI: 10.1007/s42452-020-03896-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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Gekelman W, Tang SW, DeHaas T, Vincena S, Pribyl P, Sydora R. Spiky electric and magnetic field structures in flux rope experiments. Proc Natl Acad Sci U S A 2019; 116:18239-18244. [PMID: 29925603 PMCID: PMC6744923 DOI: 10.1073/pnas.1721343115] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Magnetic flux ropes are structures that are common in the corona of the sun and presumably all stars. They can be thought of as the building blocks of solar structures. They have been observed in Earth's magnetotail and near Mars and Venus. When multiple flux ropes are present magnetic field line reconnection, which converts magnetic energy to other forms, can occur when they collide. The structure of multiple magnetic ropes, the interactions between multiple ropes, and their topological properties such as helicity and writhing have been studied theoretically and in laboratory experiments. Here, we report on spiky potential and magnetic fields associated with the ropes. We show that the potential structures are chaotic for a range of their temporal half-widths and the probability density function (PDF) of their widths resembles the statistical distribution of crumpled paper. The spatial structure of the magnetic spikes is revealed using a correlation counting method. Computer simulation suggests that the potential structures are the nonlinear end result of an instability involving relative drift between ions and electrons.
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Affiliation(s)
- W Gekelman
- Department of Physics and Astronomy, University of California, Los Angeles, CA 90095;
| | - S W Tang
- Department of Physics and Astronomy, University of California, Los Angeles, CA 90095
| | - T DeHaas
- Department of Physics and Astronomy, University of California, Los Angeles, CA 90095
| | - S Vincena
- Department of Physics and Astronomy, University of California, Los Angeles, CA 90095
| | - P Pribyl
- Department of Physics and Astronomy, University of California, Los Angeles, CA 90095
| | - R Sydora
- Department of Physics, University of Alberta, Edmonton, AB, Canada T6G 2R3
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Prior C, Yeates AR. Quantifying reconnective activity in braided vector fields. Phys Rev E 2018; 98:013204. [PMID: 30110812 DOI: 10.1103/physreve.98.013204] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Indexed: 06/08/2023]
Abstract
We introduce a technique for evaluating the changing connectivity of a vector field whose integral curves (field lines) form tangled tubular bundles. Applications of such fields include magnetic flux ropes, relativistic plasma jets, stirred two-dimensional fluids, superfluid vortices, and polymer networks. The technique is based on maps of the field line winding-the average entanglement of a given field line with all other field lines. Previously this had been developed for divergence-free vector fields. By extending some previous theoretical results, we show how it can be applied to any vector field that forms a tubular bundle. We demonstrate the efficacy of this technique on data from laboratory plasma experiments with two interacting magnetic flux ropes. Performed in the UCLA Large Plasma Device, the plasma's magnetic field structure is too complex to identify a single dominant current sheet as an expected site of magnetic reconnection. Previously, this complex structure had restricted the ability to analyze the evolving magnetic connectivity, but this is no such restriction to our method. We demonstrate that the plasma establishes a periodically oscillating cycle of magnetic field structure variation which, while triggered by an ideal instability, is dominated by magnetic reconnection. This reconnection leads to periodically varying coherence of a merged central flux rope, a conclusion supported by analysis of the writhing structure of the magnetic field.
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Affiliation(s)
- Christopher Prior
- Department of Mathematical Sciences, Durham University, Lower Mountjoy, Stockton Road, Durham DH1 3LE, United Kingdom
| | - Anthony R Yeates
- Department of Mathematical Sciences, Durham University, Lower Mountjoy, Stockton Road, Durham DH1 3LE, United Kingdom
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