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Yoo J, Ng J, Ji H, Bose S, Goodman A, Alt A, Chen LJ, Shi P, Yamada M. Anomalous Resistivity and Electron Heating by Lower Hybrid Drift Waves during Magnetic Reconnection with a Guide Field. PHYSICAL REVIEW LETTERS 2024; 132:145101. [PMID: 38640378 DOI: 10.1103/physrevlett.132.145101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Revised: 12/29/2023] [Accepted: 02/07/2024] [Indexed: 04/21/2024]
Abstract
The lower hybrid drift wave (LHDW) has been a candidate for anomalous resistivity and electron heating inside the electron diffusion region of magnetic reconnection. In a laboratory reconnection layer with a finite guide field, quasielectrostatic LHDW (ES-LHDW) propagating along the direction nearly perpendicular to the local magnetic field is excited in the electron diffusion region. ES-LHDW generates large density fluctuations (δn_{e}, about 25% of the mean density) that are correlated with fluctuations in the out-of-plane electric field (δE_{Y}, about twice larger than the mean reconnection electric field). With a small phase difference (∼30°) between two fluctuating quantities, the anomalous resistivity associated with the observed ES-LHDW is twice larger than the classical resistivity and accounts for 20% of the mean reconnection electric field. After we verify the linear relationship between δn_{e} and δE_{Y}, anomalous electron heating by LHDW is estimated by a quasilinear analysis. The estimated electron heating is about 2.6±0.3 MW/m^{3}, which exceeds the classical Ohmic heating of about 2.0±0.2 MW/m^{3}. This LHDW-driven heating is consistent with the observed trend of higher electron temperatures when the wave amplitude is larger. Presented results provide the first direct estimate of anomalous resistivity and electron heating power by LHDW, which demonstrates the importance of wave-particle interactions in magnetic reconnection.
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Affiliation(s)
- Jongsoo Yoo
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08542, USA
| | - Jonathan Ng
- Department of Astronomy, University of Maryland, College Park, Maryland 20742, USA
| | - Hantao Ji
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08542, USA
- Department of Astrophysical Sciences, Princeton University, New Jersey 08544, USA
| | - Sayak Bose
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08542, USA
| | - Aaron Goodman
- Department of Mechanical and Aerospace Engineering, Princeton University, New Jersey 08544, USA
| | - Andrew Alt
- Department of Astrophysical Sciences, Princeton University, New Jersey 08544, USA
| | - Li-Jen Chen
- NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
| | - Peiyun Shi
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08542, USA
| | - Masaaki Yamada
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08542, USA
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2
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Motoba T, Sitnov MI, Stephens GK, Gershman DJ. A New Perspective on Magnetotail Electron and Ion Divergent Flows: MMS Observations. JOURNAL OF GEOPHYSICAL RESEARCH. SPACE PHYSICS 2022; 127:e2022JA030514. [PMID: 36591322 PMCID: PMC9788156 DOI: 10.1029/2022ja030514] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Revised: 08/17/2022] [Accepted: 09/13/2022] [Indexed: 06/17/2023]
Abstract
Fast divergent flows of electrons and ions in the magnetotail plasma sheet are conventionally interpreted as a key reconnection signature caused by the magnetic topology change at the X-line. Therefore, reversals of the x-component (V x⊥) of the plasma flow perpendicular to the magnetic field must correlate with the sign changes in the north-south component of the magnetic field (B z ). Here we present observations of the flow reversals that take place with no correlated B z reversals. We report six such events, which were measured with the high-resolution plasma and fields instruments of the Magnetospheric Multiscale mission. We found that electron flow reversals in the absence of B z reversals (a) have amplitudes of ∼1,000-2,000 km s-1 and durations of a few seconds; (b) are embedded into larger-scale ion flow reversals with enhanced ion agyrotropy; and (c) compared with conventional reconnection outflows around the electron diffusion regions (EDRs), have less (if ever) pronounced electron agyrotropy, dawnward electron flow amplitude, and electric field strength toward the neutral sheet, although their energy conversion parameters, including the Joule heating rate, are quite substantial. These results suggest that such flow reversals develop in the ion-demagnetization regions away from electron-scale current sheets, in particular the EDRs, and yet they play an important role in the energy conversion. These divergent flows are interpreted as precursors of the flow-driven reconnection onsets provided by the ion tearing or the ballooning/interchange instability.
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Affiliation(s)
- T. Motoba
- The Johns Hopkins University Applied Physics LaboratoryLaurelMDUSA
| | - M. I. Sitnov
- The Johns Hopkins University Applied Physics LaboratoryLaurelMDUSA
| | - G. K. Stephens
- The Johns Hopkins University Applied Physics LaboratoryLaurelMDUSA
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3
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Oh S, Cho J, Lee J, Han J, Kim S, Nam Y. A Scalable Haze-Free Antireflective Hierarchical Surface with Self-Cleaning Capability. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2022; 9:e2202781. [PMID: 35901503 PMCID: PMC9507353 DOI: 10.1002/advs.202202781] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Revised: 07/01/2022] [Indexed: 06/15/2023]
Abstract
The lotus effect indicates that a superhydrophobic, self-cleaning surface can be obtained by roughening the topography of a hydrophobic surface. However, attaining high transmittance and clarity through a roughened surface remains challenging because of its strong scattering characteristics. Here, a haze-free, antireflective superhydrophobic surface that consists of hierarchically designed nanoparticles is demonstrated. Close-packed, deep-subwavelength-scale colloidal silica nanoparticles and their upper, chain-like fumed silica nanoparticles individually fulfill haze-free broadband antireflection and self-cleaning functions. These double-layered hierarchical surfaces are obtained via a scalable spraying process that permits precise control over the coating morphology to attain the desired optical and wetting properties. They provide a "specular" visible transmittance of >97% when double-side coated and a record-high self-cleaning capability with a near-zero sliding angle. Self-cleaning experiments on photovoltaic devices verify that the developed surfaces can significantly enhance power conversion efficiencies and aid in retaining pristine device performance in a dusty environment.
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Affiliation(s)
- Seungtae Oh
- Carbon Neutral Technology R&D DepartmentKorea Institute of Industrial Technology (KITECH)Cheonan31056Republic of Korea
| | - Jin‐Woo Cho
- Department of Applied PhysicsKyung Hee UniversityYongin17104Republic of Korea
| | - Jihun Lee
- Department of Mechanical EngineeringPohang University of Science and Technology (POSTECH)Pohang37673Republic of Korea
| | - Jeonghoon Han
- Department of Mechanical EngineeringKorea Advanced Institute of Science and Technology (KAIST)Daejeon34141Republic of Korea
| | - Sun‐Kyung Kim
- Department of Applied PhysicsKyung Hee UniversityYongin17104Republic of Korea
| | - Youngsuk Nam
- Department of Mechanical EngineeringKorea Advanced Institute of Science and Technology (KAIST)Daejeon34141Republic of Korea
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4
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Zhang H, Zong Q, Connor H, Delamere P, Facskó G, Han D, Hasegawa H, Kallio E, Kis Á, Le G, Lembège B, Lin Y, Liu T, Oksavik K, Omidi N, Otto A, Ren J, Shi Q, Sibeck D, Yao S. Dayside Transient Phenomena and Their Impact on the Magnetosphere and Ionosphere. SPACE SCIENCE REVIEWS 2022; 218:40. [PMID: 35784192 PMCID: PMC9239986 DOI: 10.1007/s11214-021-00865-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/01/2021] [Accepted: 11/11/2021] [Indexed: 06/15/2023]
Abstract
Dayside transients, such as hot flow anomalies, foreshock bubbles, magnetosheath jets, flux transfer events, and surface waves, are frequently observed upstream from the bow shock, in the magnetosheath, and at the magnetopause. They play a significant role in the solar wind-magnetosphere-ionosphere coupling. Foreshock transient phenomena, associated with variations in the solar wind dynamic pressure, deform the magnetopause, and in turn generates field-aligned currents (FACs) connected to the auroral ionosphere. Solar wind dynamic pressure variations and transient phenomena at the dayside magnetopause drive magnetospheric ultra low frequency (ULF) waves, which can play an important role in the dynamics of Earth's radiation belts. These transient phenomena and their geoeffects have been investigated using coordinated in-situ spacecraft observations, spacecraft-borne imagers, ground-based observations, and numerical simulations. Cluster, THEMIS, Geotail, and MMS multi-mission observations allow us to track the motion and time evolution of transient phenomena at different spatial and temporal scales in detail, whereas ground-based experiments can observe the ionospheric projections of transient magnetopause phenomena such as waves on the magnetopause driven by hot flow anomalies or flux transfer events produced by bursty reconnection across their full longitudinal and latitudinal extent. Magnetohydrodynamics (MHD), hybrid, and particle-in-cell (PIC) simulations are powerful tools to simulate the dayside transient phenomena. This paper provides a comprehensive review of the present understanding of dayside transient phenomena at Earth and other planets, their geoeffects, and outstanding questions.
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Affiliation(s)
- Hui Zhang
- Physics Department & Geophysical Institute, University of Alaska Fairbanks, 2156 Koyukuk Drive, Fairbanks, AK 99775 USA
- Shandong University, Weihai, China
| | - Qiugang Zong
- Institute of Space Physics and Applied Technology, Peking University, Beijing, 100871 China
- Polar Research Institute of China, Shanghai, 200136 China
| | - Hyunju Connor
- Physics Department & Geophysical Institute, University of Alaska Fairbanks, 2156 Koyukuk Drive, Fairbanks, AK 99775 USA
- NASA Goddard Space Flight Center, Greenbelt, MD 20771 USA
| | - Peter Delamere
- Physics Department & Geophysical Institute, University of Alaska Fairbanks, 2156 Koyukuk Drive, Fairbanks, AK 99775 USA
| | - Gábor Facskó
- Department of Informatics, Milton Friedman University, 1039 Budapest, Hungary
- Wigner Research Centre for Physics, Konkoly-Thege Miklós út 29-33, 1121 Budapest, Hungary
| | | | - Hiroshi Hasegawa
- Institute of Space and Astronautical Science, JAXA, Sagamihara, Japan
| | | | - Árpád Kis
- Institute of Earth Physics and Space Science (ELKH EPSS), Sopron, Hungary
| | - Guan Le
- NASA Goddard Space Flight Center, Greenbelt, MD 20771 USA
| | - Bertrand Lembège
- LATMOS (Laboratoire Atmosphères, Milieux, Observations Spatiales), IPSL/CNRS/UVSQ, 11 Bd d’Alembert, Guyancourt, 78280 France
| | - Yu Lin
- Auburn University, Auburn, USA
| | - Terry Liu
- Physics Department & Geophysical Institute, University of Alaska Fairbanks, 2156 Koyukuk Drive, Fairbanks, AK 99775 USA
- Department of Earth, Planetary, and Space Sciences, University of California, Los Angeles, Los Angeles, USA
| | - Kjellmar Oksavik
- Birkeland Centre for Space Science, Department of Physics and Technology, University of Bergen, Bergen, Norway
- Arctic Geophysics, The University Centre in Svalbard, Longyearbyen, Norway
| | | | - Antonius Otto
- Physics Department & Geophysical Institute, University of Alaska Fairbanks, 2156 Koyukuk Drive, Fairbanks, AK 99775 USA
| | - Jie Ren
- Institute of Space Physics and Applied Technology, Peking University, Beijing, 100871 China
| | | | - David Sibeck
- NASA Goddard Space Flight Center, Greenbelt, MD 20771 USA
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5
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Casner A. Recent progress in quantifying hydrodynamics instabilities and turbulence in inertial confinement fusion and high-energy-density experiments. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2021; 379:20200021. [PMID: 33280557 DOI: 10.1098/rsta.2020.0021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 09/18/2020] [Indexed: 06/12/2023]
Abstract
Since the seminal paper of Nuckolls triggering the quest of inertial confinement fusion (ICF) with lasers, hydrodynamic instabilities have been recognized as one of the principal hurdles towards ignition. This remains true nowadays for both main approaches (indirect drive and direct drive), despite the advent of MJ scale lasers with tremendous technological capabilities. From a fundamental science perspective, these gigantic laser facilities enable also the possibility to create dense plasma flows evolving towards turbulence, being magnetized or not. We review the state of the art of nonlinear hydrodynamics and turbulent experiments, simulations and theory in ICF and high-energy-density plasmas and draw perspectives towards in-depth understanding and control of these fascinating phenomena. This article is part of a discussion meeting issue 'Prospects for high gain inertial fusion energy (part 2)'.
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Affiliation(s)
- A Casner
- Université de Bordeaux-CNRS-CEA, Centre Lasers Intenses et Applications (CELIA), UMR 5107, 33405 Talence, France
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6
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Nakamura TKM, Plaschke F, Hasegawa H, Liu Y, Hwang K, Blasl KA, Nakamura R. Decay of Kelvin-Helmholtz Vortices at the Earth's Magnetopause Under Pure Southward IMF Conditions. GEOPHYSICAL RESEARCH LETTERS 2020; 47:e2020GL087574. [PMID: 32999512 PMCID: PMC7507125 DOI: 10.1029/2020gl087574] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Revised: 05/20/2020] [Accepted: 06/05/2020] [Indexed: 06/11/2023]
Abstract
At the Earth's low-latitude magnetopause, clear signatures of the Kelvin-Helmholtz (KH) waves have been frequently observed during periods of the northward interplanetary magnetic field (IMF), whereas these signatures have been much less frequently observed during the southward IMF. Here, we performed the first 3-D fully kinetic simulation of the magnetopause KH instability under the southward IMF condition. The simulation demonstrates that fast magnetic reconnection is induced at multiple locations along the vortex edge in an early nonlinear growth phase of the instability. The reconnection outflow jets significantly disrupt the flow of the nonlinear KH vortex, while the disrupted turbulent flow strongly bends and twists the reconnected field lines. The resulting coupling of the complex field and flow patterns within the magnetopause boundary layer leads to a quick decay of the vortex structure, which may explain the difference in the observation probability of KH waves between northward and southward IMF conditions.
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Affiliation(s)
| | - F. Plaschke
- Space Research InstituteAustrian Academy of SciencesGrazAustria
| | - H. Hasegawa
- Institute of Space and Astronautical ScienceJapan Aerospace Exploration AgencySagamiharaJapan
| | - Y.‐H. Liu
- Department of Physics and AstronomyDartmouth CollegeHanoverNHUSA
| | - K.‐J. Hwang
- Southwest Research InstituteSan AntonioTXUSA
| | - K. A. Blasl
- Space Research InstituteAustrian Academy of SciencesGrazAustria
- Institute of PhysicsUniversity of GrazGrazAustria
| | - R. Nakamura
- Space Research InstituteAustrian Academy of SciencesGrazAustria
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7
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Hwang K, Dokgo K, Choi E, Burch JL, Sibeck DG, Giles BL, Hasegawa H, Fu HS, Liu Y, Wang Z, Nakamura TKM, Ma X, Fear RC, Khotyaintsev Y, Graham DB, Shi QQ, Escoubet CP, Gershman DJ, Paterson WR, Pollock CJ, Ergun RE, Torbert RB, Dorelli JC, Avanov L, Russell CT, Strangeway RJ. Magnetic Reconnection Inside a Flux Rope Induced by Kelvin-Helmholtz Vortices. JOURNAL OF GEOPHYSICAL RESEARCH. SPACE PHYSICS 2020; 125:e2019JA027665. [PMID: 32714734 PMCID: PMC7375157 DOI: 10.1029/2019ja027665] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Revised: 01/29/2020] [Accepted: 03/03/2020] [Indexed: 06/11/2023]
Abstract
On 5 May 2017, MMS observed a crater-type flux rope on the dawnside tailward magnetopause with fluctuations. The boundary-normal analysis shows that the fluctuations can be attributed to nonlinear Kelvin-Helmholtz (KH) waves. Reconnection signatures such as flow reversals and Joule dissipation were identified at the leading and trailing edges of the flux rope. In particular, strong northward electron jets observed at the trailing edge indicated midlatitude reconnection associated with the 3-D structure of the KH vortex. The scale size of the flux rope, together with reconnection signatures, strongly supports the interpretation that the flux rope was generated locally by KH vortex-induced reconnection. The center of the flux rope also displayed signatures of guide-field reconnection (out-of-plane electron jets, parallel electron heating, and Joule dissipation). These signatures indicate that an interface between two interlinked flux tubes was undergoing interaction, causing a local magnetic depression, resulting in an M-shaped crater flux rope, as supported by reconstruction.
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Affiliation(s)
- K.‐J. Hwang
- Southwest Research InstituteSan AntonioTXUSA
| | - K. Dokgo
- Southwest Research InstituteSan AntonioTXUSA
| | - E. Choi
- Southwest Research InstituteSan AntonioTXUSA
| | - J. L. Burch
- Southwest Research InstituteSan AntonioTXUSA
| | | | - B. L. Giles
- NASA Goddard Space Flight CenterGreenbeltMDUSA
| | - H. Hasegawa
- Institute of Space and Astronautical ScienceJapan Aerospace Exploration AgencySagamiharaJapan
| | - H. S. Fu
- School of Science and EnvironmentBeihang UniversityBeijingChina
| | - Y. Liu
- School of Science and EnvironmentBeihang UniversityBeijingChina
| | - Z. Wang
- School of Science and EnvironmentBeihang UniversityBeijingChina
| | | | - X. Ma
- Physical Sciences DepartmentEmbry‐Riddle Aeronautical UniversityDaytona BeachFLUSA
| | - R. C. Fear
- School of Physics and AstronomyUniversity of SouthamptonSouthamptonUK
| | | | | | - Q. Q. Shi
- School of Earth and Space SciencesPeking UniversityPekingChina
| | - C. P. Escoubet
- European Space Research and Technology CentreNoordwijkthe Netherlands
| | | | | | | | - R. E. Ergun
- Laboratory for Atmospheric and Space PhysicsUniversity of Colorado at BoulderBoulderCOUSA
| | - R. B. Torbert
- Space Science CenterUniversity of New HampshireDurhamNHUSA
| | | | - L. Avanov
- NASA Goddard Space Flight CenterGreenbeltMDUSA
- The Goddard Planetary Heliophysics InstituteUniversity of Maryland, Baltimore CountyBaltimoreMDUSA
| | - C. T. Russell
- Institute of Geophysics and Planetary PhysicsUniversity of California, Los AngelesLos AngelesCAUSA
| | - R. J. Strangeway
- Institute of Geophysics and Planetary PhysicsUniversity of California, Los AngelesLos AngelesCAUSA
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8
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Evolution of Turbulence in the Kelvin–Helmholtz Instability in the Terrestrial Magnetopause. ATMOSPHERE 2019. [DOI: 10.3390/atmos10090561] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The dynamics occurring at the terrestrial magnetopause are investigated by using Geotail and THEMIS spacecraft data of magnetopause crossings during ongoing Kelvin–Helmholtz instability. Properties of plasma turbulence and intermittency are presented, with the aim of understanding the evolution of the turbulence as a result of the development of Kelvin–Helmholtz instability. The data have been tested against standard diagnostics for intermittent turbulence, such as the autocorrelation function, the spectral analysis and the scale-dependent statistics of the magnetic field increments. A quasi-periodic modulation of different scaling exponents may exist along the direction of propagation of the Kelvin–Helmholtz waves along the Geocentric Solar Magnetosphere coordinate system (GSM), and it is visible as a quasi-periodic modulation of the scaling exponents we have studied. The wave period associated with such oscillation was estimated to be approximately 6.4 Earth Radii ( R E ). Furthermore, the amplitude of such modulation seems to decrease as the measurements are taken further away from the Earth along the magnetopause, in particular after X ( G S M ) ≲ − 15 R E . The observed modulation seems to persist for most of the parameters considered in this analysis. This suggests that a kind of signature related to the development of the Kelvin–Helmholtz instabilities could be present in the statistical properties of the magnetic turbulence.
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Abstract
Shear flows are ubiquitously present in space and astrophysical plasmas. This paper highlights the central idea of the non-thermal acceleration of charged particles in shearing flows and reviews some of the recent developments. Topics include the acceleration of charged particles by microscopic instabilities in collisionless relativistic shear flows, Fermi-type particle acceleration in macroscopic, gradual and non-gradual shear flows, as well as shear particle acceleration by large-scale velocity turbulence. When put in the context of jetted astrophysical sources such as Active Galactic Nuclei, the results illustrate a variety of means beyond conventional diffusive shock acceleration by which power-law like particle distributions might be generated. This suggests that relativistic shear flows can account for efficient in-situ acceleration of energetic electrons and be of relevance for the production of extreme cosmic rays.
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10
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Sorathia KA, Merkin VG, Ukhorskiy AY, Allen RC, Nykyri K, Wing S. Solar Wind Ion Entry Into the Magnetosphere During Northward IMF. JOURNAL OF GEOPHYSICAL RESEARCH. SPACE PHYSICS 2019; 124:5461-5481. [PMID: 31598452 PMCID: PMC6774285 DOI: 10.1029/2019ja026728] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Revised: 05/20/2019] [Accepted: 05/29/2019] [Indexed: 05/22/2023]
Abstract
Extended periods of northward interplanetary magnetic field (IMF) lead to the formation of a cold, dense plasma sheet due to the entry of solar wind plasma into the magnetosphere. Identifying the paths that the solar wind takes to enter the magnetosphere, and their relative importance has remained elusive. Any theoretical model of entry must satisfy observational constraints, such as the overall entry rate and the dawn-dusk asymmetry observed in the cold, dense plasma sheet. We model, using a combination of global magnetohydrodynamic and test particle simulations, solar wind ion entry into the magnetosphere during northward IMF and compare entry facilitated by the Kelvin-Helmholtz instability to cusp reconnection. For Kelvin-Helmholtz entry we reproduce transport rates inferred from observation and kinetic modeling and find that intravortex reconnection creates buoyant flux tubes, which provides, through interchange instability, a mechanism of filling the central plasma sheet with cold magnetosheath plasma. For cusp entry we show that an intrinsic dawn-dusk asymmetry is created during entry that is the result of alignment of the westward ion drift with the dawnward electric field typically observed during northward IMF. We show that both entry mechanisms provide comparable mass but affect entering plasma differently. The flank-entering plasma is cold and dawn-dusk symmetric, whereas the cusp-entering plasma is accelerated and preferentially deflected toward dawn. The combined effect of these entry mechanisms results in a plasma sheet population that exhibits dawn-dusk asymmetry in the manner that is seen in nature: a two-component (hot and cold) dusk flank and hotter, broadly peaked dawn population.
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Affiliation(s)
- K. A. Sorathia
- The Johns Hopkins University Applied Physics LaboratoryLaurelMDUSA
| | - V. G. Merkin
- The Johns Hopkins University Applied Physics LaboratoryLaurelMDUSA
| | - A. Y. Ukhorskiy
- The Johns Hopkins University Applied Physics LaboratoryLaurelMDUSA
| | - R. C. Allen
- The Johns Hopkins University Applied Physics LaboratoryLaurelMDUSA
| | - K. Nykyri
- Center for Space and Atmospheric ResearchEmbry‐Riddle Aeronautical UniversityDaytona BeachFLUSA
| | - S. Wing
- The Johns Hopkins University Applied Physics LaboratoryLaurelMDUSA
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11
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Palmroth M, Ganse U, Pfau-Kempf Y, Battarbee M, Turc L, Brito T, Grandin M, Hoilijoki S, Sandroos A, von Alfthan S. Vlasov methods in space physics and astrophysics. ACTA ACUST UNITED AC 2018; 4:1. [PMID: 30680308 PMCID: PMC6319499 DOI: 10.1007/s41115-018-0003-2] [Citation(s) in RCA: 68] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Accepted: 07/06/2018] [Indexed: 11/26/2022]
Abstract
This paper reviews Vlasov-based numerical methods used to model plasma in space physics and astrophysics. Plasma consists of collectively behaving charged particles that form the major part of baryonic matter in the Universe. Many concepts ranging from our own planetary environment to the Solar system and beyond can be understood in terms of kinetic plasma physics, represented by the Vlasov equation. We introduce the physical basis for the Vlasov system, and then outline the associated numerical methods that are typically used. A particular application of the Vlasov system is Vlasiator, the world’s first global hybrid-Vlasov simulation for the Earth’s magnetic domain, the magnetosphere. We introduce the design strategies for Vlasiator and outline its numerical concepts ranging from solvers to coupling schemes. We review Vlasiator’s parallelisation methods and introduce the used high-performance computing (HPC) techniques. A short review of verification, validation and physical results is included. The purpose of the paper is to present the Vlasov system and introduce an example implementation, and to illustrate that even with massive computational challenges, an accurate description of physics can be rewarding in itself and significantly advance our understanding. Upcoming supercomputing resources are making similar efforts feasible in other fields as well, making our design options relevant for others facing similar challenges.
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Affiliation(s)
- Minna Palmroth
- Department of Physics, University of Helsinki, Helsinki, Finland
- Finnish Meteorological Institute, Helsinki, Finland
| | - Urs Ganse
- Department of Physics, University of Helsinki, Helsinki, Finland
| | - Yann Pfau-Kempf
- Department of Physics, University of Helsinki, Helsinki, Finland
| | - Markus Battarbee
- Department of Physics, University of Helsinki, Helsinki, Finland
| | - Lucile Turc
- Department of Physics, University of Helsinki, Helsinki, Finland
| | - Thiago Brito
- Department of Physics, University of Helsinki, Helsinki, Finland
| | - Maxime Grandin
- Department of Physics, University of Helsinki, Helsinki, Finland
| | - Sanni Hoilijoki
- Laboratory for Atmospheric and Space Plasma Physics, University of Colorado at Boulder, Boulder, CO USA
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12
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Liu YH, Hesse M, Guo F, Li H, Nakamura TKM. Strongly localized magnetic reconnection by the super-Alfvénic shear flow. PHYSICS OF PLASMAS 2018; 25:080701. [PMID: 30224858 PMCID: PMC6137741 DOI: 10.1063/1.5042539] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Accepted: 07/23/2018] [Indexed: 06/08/2023]
Abstract
We demonstrate that the dragging of the magnetic field by the super-Alfvénic shear flows out of the reconnection plane can strongly localize the reconnection x-line in collisionless pair plasmas, reversing the current direction at the x-line. Reconnection with this new morphology, which is impossible in resistive-magnetohydrodynamics, is enabled by the particle inertia. Surprisingly, the quasi-steady reconnection rate remains of order 0.1 even though the aspect ratio of the local x-line geometry is larger than unity, which completely excludes the role of tearing physics. We explain this by examining the transport of the reconnected magnetic flux and the opening angle ma de by the upstream magnetic field, concluding that the reconnection rate is still limited by the constraint imposed at the inflow region. Based on these findings, we propose that this often observed fast rate value of order 0.1 itself, in general, is an upper bound value determined by the upstream constraint, independent of the localization mechanism and dissipation therein.
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Affiliation(s)
- Yi-Hsin Liu
- Dartmouth College, Hanover, New Hampshire 03750, USA
| | - M Hesse
- University of Bergen, Bergen, Norway
- Southwest Research Institute, San Antonio, Texas 78238, USA
| | - F Guo
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - H Li
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - T K M Nakamura
- Space Research Institute, Austrian Academy of Sciences, Graz 8010, Austria
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