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Hasegawa H, Denton RE, Dokgo K, Hwang K, Nakamura TKM, Burch JL. Ion-Scale Magnetic Flux Rope Generated From Electron-Scale Magnetopause Current Sheet: Magnetospheric Multiscale Observations. JOURNAL OF GEOPHYSICAL RESEARCH. SPACE PHYSICS 2023; 128:e2022JA031092. [PMID: 38440152 PMCID: PMC10909477 DOI: 10.1029/2022ja031092] [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: 10/17/2022] [Revised: 03/05/2023] [Accepted: 03/08/2023] [Indexed: 03/06/2024]
Abstract
We present in-depth analysis of three southward-moving meso-scale (ion-to magnetohydrodynamic-scale) flux transfer events (FTEs) and subsequent crossing of a reconnecting magnetopause current sheet (MPCS), which were observed on 8 December 2015 by the Magnetospheric Multiscale spacecraft in the subsolar region under southward and duskward magnetosheath magnetic field conditions. We aim to understand the generation mechanism of ion-scale magnetic flux ropes (ISFRs) and to reveal causal relationship among magnetic field structures, electromagnetic energy conversion, and kinetic processes in magnetic reconnection layers. Results from magnetic field reconstruction methods are consistent with a flux rope with a length of about one ion inertial length growing from an electron-scale current sheet (ECS) in the MPCS, supporting the idea that ISFRs can be generated through secondary reconnection in an ECS. Grad-Shafranov reconstruction applied to the three FTEs shows that the FTEs had axial orientations similar to that of the ISFR. This suggests that these FTEs also formed through the same secondary reconnection process, rather than multiple X-line reconnection at spatially separated locations. Four-spacecraft observations of electron pitch-angle distributions and energy conversion rate j · E ' = j · E + v e × B suggest that the ISFR had three-dimensional magnetic topology and secondary reconnection was patchy or bursty. Previously reported positive and negative values of j · E ' , with magnitudes much larger than expected for typical MP reconnection, were seen in both magnetosheath and magnetospheric separatrix regions of the ISFR. Many of them coexisted with bi-directional electron beams and intense electric field fluctuations around the electron gyrofrequency, consistent with their origin in separatrix activities.
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Affiliation(s)
- H. Hasegawa
- Institute of Space and Astronautical ScienceJapan Aerospace Exploration AgencySagamiharaJapan
- Southwest Research InstituteSan AntonioTXUSA
| | - R. E. Denton
- Department of Physics and AstronomyDartmouth CollegeHanoverNHUSA
| | - K. Dokgo
- Southwest Research InstituteSan AntonioTXUSA
| | - K.‐J. Hwang
- Southwest Research InstituteSan AntonioTXUSA
| | | | - J. L. Burch
- Southwest Research InstituteSan AntonioTXUSA
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Ala‐Lahti M, Pulkkinen TI, Pfau‐Kempf Y, Grandin M, Palmroth M. Energy Flux Through the Magnetopause During Flux Transfer Events in Hybrid-Vlasov 2D Simulations. GEOPHYSICAL RESEARCH LETTERS 2022; 49:e2022GL100079. [PMID: 36591573 PMCID: PMC9788168 DOI: 10.1029/2022gl100079] [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: 06/16/2022] [Revised: 09/02/2022] [Accepted: 09/23/2022] [Indexed: 06/17/2023]
Abstract
Solar wind-magnetosphere coupling drives magnetospheric dynamic phenomena by enabling energy exchange between magnetospheric and solar wind plasmas. In this study, we examine two-dimensional noon-midnight meridional plane simulation runs of the global hybrid-Vlasov code Vlasiator with southward interplanetary magnetic field driving. We compute the energy flux, which consists of the Poynting flux and hydrodynamic energy flux components, through the Earth's magnetopause during flux transfer events (FTEs). The results demonstrate the spatiotemporal variations of the energy flux along the magnetopause during an FTE, associating the FTE leading (trailing) edge with an energy injection into (escape from) the magnetosphere on the dayside. Furthermore, FTEs traveling along the magnetopause transport energy to the nightside magnetosphere. We identify the tail lobes as a primary entry region for solar wind energy into the magnetosphere, consistent with results from global magnetohydrodynamic simulations and observations.
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Affiliation(s)
- Matti Ala‐Lahti
- Department of Climate and Space Sciences and EngineeringUniversity of MichiganAnn ArborMIUSA
- Department of PhysicsUniversity of HelsinkiHelsinkiFinland
| | - Tuija I. Pulkkinen
- Department of Climate and Space Sciences and EngineeringUniversity of MichiganAnn ArborMIUSA
| | | | - Maxime Grandin
- Department of PhysicsUniversity of HelsinkiHelsinkiFinland
| | - Minna Palmroth
- Department of PhysicsUniversity of HelsinkiHelsinkiFinland
- Space and Earth Observation CentreFinnish Meteorological InstituteHelsinkiFinland
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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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Li X, Wang R, Lu Q, Russell CT, Lu S, Cohen IJ, Ergun RE, Wang S. Three-dimensional network of filamentary currents and super-thermal electrons during magnetotail magnetic reconnection. Nat Commun 2022; 13:3241. [PMID: 35688827 PMCID: PMC9187682 DOI: 10.1038/s41467-022-31025-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2021] [Accepted: 05/24/2022] [Indexed: 11/24/2022] Open
Abstract
Magnetic reconnection is a fundamental plasma process by which magnetic field lines on two sides of the current sheet flow inward to yield an X-line topology. It is responsible for producing energetic electrons in explosive phenomena in space, astrophysical, and laboratorial plasmas. The X-line region is supposed to be the important place for generating energetic electrons. However, how these energetic electrons are generated in such a limited region is still poorly understood. Here, using Magnetospheric multiscale mission data acquired in Earth’s magnetotail, we present direct evidence of super-thermal electrons up to 300 keV inside an X-line region, and the electrons display a power-law spectrum with an index of about 8.0. Concurrently, three-dimensional network of dynamic filamentary currents in electron scale is observed and leads to electromagnetic turbulence therein. The observations indicate that the electrons are effectively accelerated while the X-line region evolves into turbulence with a complex filamentary current network. Magnetotail reconnection plays an important role in explosive energy conversion. Here, the authors show direct evidence of super-thermal electrons up to 300 keV within X-line region in Earth’s magnetotail, indicating effective electron acceleration due to turbulence.
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Affiliation(s)
- Xinmin Li
- CAS Key Laboratory of Geospace Environment, Department of Geophysics and Planetary Science, University of Science and Technology of China, Hefei, 230026, China.,CAS Center for Excellence in Comparative Planetology, Hefei, China.,Anhui Mengcheng Geophysics National Observation and Research Station, University of Science and Technology of China, Mengcheng, 233500, Anhui, China
| | - Rongsheng Wang
- CAS Key Laboratory of Geospace Environment, Department of Geophysics and Planetary Science, University of Science and Technology of China, Hefei, 230026, China. .,CAS Center for Excellence in Comparative Planetology, Hefei, China. .,Anhui Mengcheng Geophysics National Observation and Research Station, University of Science and Technology of China, Mengcheng, 233500, Anhui, China.
| | - Quanming Lu
- CAS Key Laboratory of Geospace Environment, Department of Geophysics and Planetary Science, University of Science and Technology of China, Hefei, 230026, China. .,CAS Center for Excellence in Comparative Planetology, Hefei, China. .,Anhui Mengcheng Geophysics National Observation and Research Station, University of Science and Technology of China, Mengcheng, 233500, Anhui, China.
| | - Christopher T Russell
- Earth Planetary and Space Sciences, University of California, Los Angeles, CA, 90095, USA
| | - San Lu
- CAS Key Laboratory of Geospace Environment, Department of Geophysics and Planetary Science, University of Science and Technology of China, Hefei, 230026, China.,CAS Center for Excellence in Comparative Planetology, Hefei, China.,Anhui Mengcheng Geophysics National Observation and Research Station, University of Science and Technology of China, Mengcheng, 233500, Anhui, China
| | - Ian J Cohen
- The Johns Hopkins University Applied Physics Laboratory, Laurel, MD, USA
| | - R E Ergun
- Department for Astrophysical and Planetary Sciences, University of Colorado, Boulder, CO, USA
| | - Shui Wang
- CAS Key Laboratory of Geospace Environment, Department of Geophysics and Planetary Science, University of Science and Technology of China, Hefei, 230026, China.,CAS Center for Excellence in Comparative Planetology, Hefei, China.,Anhui Mengcheng Geophysics National Observation and Research Station, University of Science and Technology of China, Mengcheng, 233500, Anhui, China
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Trattner KJ, Petrinec SM, Fuselier SA. The Location of Magnetic Reconnection at Earth's Magnetopause. SPACE SCIENCE REVIEWS 2021; 217:41. [PMID: 34720216 PMCID: PMC8550343 DOI: 10.1007/s11214-021-00817-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Accepted: 03/08/2021] [Indexed: 06/13/2023]
Abstract
One of the major questions about magnetic reconnection is how specific solar wind and interplanetary magnetic field conditions influence where reconnection occurs at the Earth's magnetopause. There are two reconnection scenarios discussed in the literature: a) anti-parallel reconnection and b) component reconnection. Early spacecraft observations were limited to the detection of accelerated ion beams in the magnetopause boundary layer to determine the general direction of the reconnection X-line location with respect to the spacecraft. An improved view of the reconnection location at the magnetopause evolved from ionospheric emissions observed by polar-orbiting imagers. These observations and the observations of accelerated ion beams revealed that both scenarios occur at the magnetopause. Improved methodology using the time-of-flight effect of precipitating ions in the cusp regions and the cutoff velocity of the precipitating and mirroring ion populations was used to pinpoint magnetopause reconnection locations for a wide range of solar wind conditions. The results from these methodologies have been used to construct an empirical reconnection X-line model known as the Maximum Magnetic Shear model. Since this model's inception, several tests have confirmed its validity and have resulted in modifications to the model for certain solar wind conditions. This review article summarizes the observational evidence for the location of magnetic reconnection at the Earth's magnetopause, emphasizing the properties and efficacy of the Maximum Magnetic Shear Model.
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Affiliation(s)
| | | | - S. A. Fuselier
- Southwest Research Institute, San Antonio, TX USA
- University of Texas at San Antonio, San Antonio, TX USA
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Direct evidence of secondary reconnection inside filamentary currents of magnetic flux ropes during magnetic reconnection. Nat Commun 2020; 11:3964. [PMID: 32769991 PMCID: PMC7415135 DOI: 10.1038/s41467-020-17803-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Accepted: 07/09/2020] [Indexed: 11/16/2022] Open
Abstract
Magnetic reconnection is a fundamental plasma process, by which magnetic energy is explosively released in the current sheet to energize charged particles and to create bi-directional Alfvénic plasma jets. Numerical simulations predicted that evolution of the reconnecting current sheet is dominated by formation and interaction of magnetic flux ropes, which finally leads to turbulence. Accordingly, most volume of the reconnecting current sheet is occupied by the ropes, and energy dissipation occurs via multiple relevant mechanisms, e.g., the parallel electric field, the rope coalescence and the rope contraction. As an essential element of the reconnecting current sheet, however, how these ropes evolve has been elusive. Here, we present direct evidence of secondary reconnection in the filamentary currents within the ropes. The observations indicate that secondary reconnection can make a significant contribution to energy conversion in the kinetic scale during turbulent reconnection. Magnetic reconnection is a fundamental plasma process of magnetic energy conversion to kinetic energy. Here, the authors show direct evidence of secondary reconnection in the filamentary currents within the flux ropes indicating a significant contribution to energy conversion in the kinetic scale during turbulent reconnection.
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Akhavan‐Tafti M, Palmroth M, Slavin JA, Battarbee M, Ganse U, Grandin M, Le G, Gershman DJ, Eastwood JP, Stawarz JE. Comparative Analysis of the Vlasiator Simulations and MMS Observations of Multiple X-Line Reconnection and Flux Transfer Events. JOURNAL OF GEOPHYSICAL RESEARCH. SPACE PHYSICS 2020; 125:e2019JA027410. [PMID: 32999805 PMCID: PMC7507759 DOI: 10.1029/2019ja027410] [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: 09/13/2019] [Revised: 03/15/2020] [Accepted: 04/13/2020] [Indexed: 06/11/2023]
Abstract
The Vlasiator hybrid-Vlasov code was developed to investigate global magnetospheric dynamics at ion-kinetic scales. Here we focus on the role of magnetic reconnection in the formation and evolution of magnetic islands at the low-latitude magnetopause, under southward interplanetary magnetic field conditions. The simulation results indicate that (1) the magnetic reconnection ion kinetics, including the Earthward pointing Larmor electric field on the magnetospheric side of an X-point and anisotropic ion distributions, are well-captured by Vlasiator, thus enabling the study of reconnection-driven magnetic island evolution processes, (2) magnetic islands evolve due to continuous reconnection at adjacent X-points, "coalescence" which refers to the merging of neighboring islands to create a larger island, "erosion" during which an island loses magnetic flux due to reconnection, and "division" which involves the splitting of an island into smaller islands, and (3) continuous reconnection at adjacent X-points is the dominant source of magnetic flux and plasma to the outer layers of magnetic islands resulting in cross-sectional growth rates up to + 0.3 RE 2/min. The simulation results are compared to the Magnetospheric Multiscale (MMS) measurements of a chain of ion-scale flux transfer events (FTEs) sandwiched between two dominant X-lines. The MMS measurements similarly reveal (1) anisotropic ion populations and (2) normalized reconnection rate ~0.18, in agreement with theory and the Vlasiator predictions. Based on the simulation results and the MMS measurements, it is estimated that the observed ion-scale FTEs may grow Earth-sized within ~10 min, which is comparable to the average transport time for FTEs formed in the subsolar region to the high-latitude magnetopause. Future simulations shall revisit reconnection-driven island evolution processes with improved spatial resolutions.
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Affiliation(s)
- M. Akhavan‐Tafti
- Climate and Space Sciences and EngineeringUniversity of MichiganAnn ArborMIUSA
- Laboratoire de Physique des Plasmas (LPP), École Polytechnique, CNRSSorbonne Université, Institut Polytechnique de ParisPalaiseauFrance
| | - M. Palmroth
- Department of PhysicsUniversity of HelsinkiHelsinkiFinland
| | - J. A. Slavin
- Climate and Space Sciences and EngineeringUniversity of MichiganAnn ArborMIUSA
| | - M. Battarbee
- Department of PhysicsUniversity of HelsinkiHelsinkiFinland
| | - U. Ganse
- Department of PhysicsUniversity of HelsinkiHelsinkiFinland
| | - M. Grandin
- Department of PhysicsUniversity of HelsinkiHelsinkiFinland
| | - G. Le
- NASA Goddard Space Flight CenterGreenbeltMDUSA
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Smith AW, Jackman CM, Frohmaier CM, Fear RC, Slavin JA, Coxon JC. Evaluating Single Spacecraft Observations of Planetary Magnetotails With Simple Monte Carlo Simulations: 2. Magnetic Flux Rope Signature Selection Effects. JOURNAL OF GEOPHYSICAL RESEARCH. SPACE PHYSICS 2018; 123:10124-10138. [PMID: 31008004 PMCID: PMC6472627 DOI: 10.1029/2018ja025959] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/01/2018] [Revised: 10/25/2018] [Accepted: 11/20/2018] [Indexed: 06/09/2023]
Abstract
A Monte Carlo method of investigating the effects of placing selection criteria on the magnetic signature of in situ encounters with flux ropes is presented. The technique is applied to two recent flux rope surveys of MESSENGER data within the Hermean magnetotail. It is found that the different criteria placed upon the signatures will preferentially identify slightly different subsets of the underlying population. Quantifying the selection biases first allows the distributions of flux rope parameters to be corrected, allowing a more accurate estimation of the intrinsic distributions. This is shown with regard to the distribution of flux rope radii observed. When accounting for the selection criteria, the mean radius of Hermean magnetotail quasi-force-free flux ropes is found to be 58 9 - 269 + 273 km. Second, it is possible to weight the known identifications in order to determine a rate of recurrence that accounts for the presence of the structures that will not be identified. In the case of the Hermean magnetotail, the average rate of quasi-force-free flux ropes is found to 0.12 min-1 when selection effects are accounted for (up from 0.05 min-1 previously inferred from observations).
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Affiliation(s)
- A. W. Smith
- Department of Physics and AstronomyUniversity of SouthamptonSouthamptonUK
| | - C. M. Jackman
- Department of Physics and AstronomyUniversity of SouthamptonSouthamptonUK
| | - C. M. Frohmaier
- Institute of Cosmology and GravitationUniversity of PortsmouthPortsmouthUK
| | - R. C. Fear
- Department of Physics and AstronomyUniversity of SouthamptonSouthamptonUK
| | - J. A. Slavin
- Climate and Space Sciences and EngineeringUniversity of MichiganAnn ArborMIUSA
| | - J. C. Coxon
- Department of Physics and AstronomyUniversity of SouthamptonSouthamptonUK
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