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Zhang C, Nilsson H, Ebihara Y, Yamauchi M, Persson M, Rong Z, Zhong J, Dong C, Chen Y, Zhou X, Sun Y, Harada Y, Halekas J, Xu S, Futaana Y, Shi Z, Yuan C, Yun X, Fu S, Gao J, Holmström M, Wei Y, Barabash S. Detection of magnetospheric ion drift patterns at Mars. Nat Commun 2023; 14:6866. [PMID: 37891189 PMCID: PMC10611764 DOI: 10.1038/s41467-023-42630-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Accepted: 10/13/2023] [Indexed: 10/29/2023] Open
Abstract
Mars lacks a global magnetic field, and instead possesses small-scale crustal magnetic fields, making its magnetic environment fundamentally different from intrinsic magnetospheres like those of Earth or Saturn. Here we report the discovery of magnetospheric ion drift patterns, typical of intrinsic magnetospheres, at Mars using measurements from Mars Atmosphere and Volatile EvolutioN mission. Specifically, we observe wedge-like dispersion structures of hydrogen ions exhibiting butterfly-shaped distributions (pitch angle peaks at 22.5°-45° and 135°-157.5°) within the Martian crustal fields, a feature previously observed only in planetary-scale intrinsic magnetospheres. These dispersed structures are the results of drift motions that fundamentally resemble those observed in intrinsic magnetospheres. Our findings indicate that the Martian magnetosphere embodies an intermediate case where both the unmagnetized and magnetized ion behaviors could be observed because of the wide range of strengths and spatial scales of the crustal magnetic fields around Mars.
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Affiliation(s)
- Chi Zhang
- Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, China
- College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing, China
- Center for Space Physics and Department of Astronomy, Boston University, Boston, MA, USA
| | - Hans Nilsson
- Swedish Institute of Space Physics, Kiruna, Sweden
| | - Yusuke Ebihara
- Research Institute for Sustainable Humanosphere, Kyoto University, Uji, Japan
| | | | - Moa Persson
- Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Japan
| | - Zhaojin Rong
- Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, China.
- College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing, China.
| | - Jun Zhong
- Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, China
- College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Chuanfei Dong
- Center for Space Physics and Department of Astronomy, Boston University, Boston, MA, USA
| | - Yuxi Chen
- Center for Space Physics and Department of Astronomy, Boston University, Boston, MA, USA
| | - Xuzhi Zhou
- School of Earth and Space Sciences, Peking University, Beijing, China
| | - Yixin Sun
- School of Earth and Space Sciences, Peking University, Beijing, China
| | - Yuki Harada
- Department of Geophysics, Graduate School of Science, Kyoto University, Kyoto, Japan
| | - Jasper Halekas
- Department of Physics and Astronomy, University of Iowa, Iowa City, IA, USA
| | - Shaosui Xu
- Space Sciences Laboratory, University of California, Berkeley, Berkeley, CA, USA
| | | | - Zhen Shi
- Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, China
- College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Chongjing Yuan
- Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, China
- College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Xiaotong Yun
- Department of Space Physics, School of Electronic Information, Wuhan University, Wuhan, China
| | - Song Fu
- Department of Space Physics, School of Electronic Information, Wuhan University, Wuhan, China
| | - Jiawei Gao
- Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, China
- College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing, China
| | | | - Yong Wei
- Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, China.
- College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing, China.
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Richard L, Khotyaintsev YV, Graham DB, Vaivads A, Gershman DJ, Russell CT. Fast Ion Isotropization by Current Sheet Scattering in Magnetic Reconnection Jets. PHYSICAL REVIEW LETTERS 2023; 131:115201. [PMID: 37774258 DOI: 10.1103/physrevlett.131.115201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Revised: 06/22/2023] [Accepted: 08/07/2023] [Indexed: 10/01/2023]
Abstract
We present a statistical analysis of ion distributions in magnetic reconnection jets using data from the Magnetospheric Multiscale spacecraft. Compared with the quiet plasma in which the jet propagates, we often find anisotropic and non-Maxwellian ion distributions in the plasma jets. We observe magnetic field fluctuations associated with unstable ion distributions, but the wave amplitudes are not large enough to scatter ions during the observed travel time of the jet. We estimate that the phase-space diffusion due to chaotic and quasiadiabatic ion motion in the current sheet is sufficiently fast to be the primary process leading to isotropization.
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Affiliation(s)
- Louis Richard
- Swedish Institute of Space Physics, Uppsala 751 21, Sweden and Department of Physics and Astronomy, Space and Plasma Physics, Uppsala University, Uppsala 751 20, Sweden
| | | | | | - Andris Vaivads
- Division of Space and Plasma Physics, KTH Royal Institute of Technology, Stockholm 100 44, Sweden, and Ventspils University of Applied Sciences, Ventspils 3601, Latvia
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Angelopoulos V, Zhang XJ, Artemyev AV, Mourenas D, Tsai E, Wilkins C, Runov A, Liu J, Turner DL, Li W, Khurana K, Wirz RE, Sergeev VA, Meng X, Wu J, Hartinger MD, Raita T, Shen Y, An X, Shi X, Bashir MF, Shen X, Gan L, Qin M, Capannolo L, Ma Q, Russell CL, Masongsong EV, Caron R, He I, Iglesias L, Jha S, King J, Kumar S, Le K, Mao J, McDermott A, Nguyen K, Norris A, Palla A, Roosnovo A, Tam J, Xie E, Yap RC, Ye S, Young C, Adair LA, Shaffer C, Chung M, Cruce P, Lawson M, Leneman D, Allen M, Anderson M, Arreola-Zamora M, Artinger J, Asher J, Branchevsky D, Cliffe M, Colton K, Costello C, Depe D, Domae BW, Eldin S, Fitzgibbon L, Flemming A, Frederick DM, Gilbert A, Hesford B, Krieger R, Lian K, McKinney E, Miller JP, Pedersen C, Qu Z, Rozario R, Rubly M, Seaton R, Subramanian A, Sundin SR, Tan A, Thomlinson D, Turner W, Wing G, Wong C, Zarifian A. Energetic Electron Precipitation Driven by Electromagnetic Ion Cyclotron Waves from ELFIN's Low Altitude Perspective. SPACE SCIENCE REVIEWS 2023; 219:37. [PMID: 37448777 PMCID: PMC10335998 DOI: 10.1007/s11214-023-00984-w] [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: 11/01/2022] [Accepted: 06/28/2023] [Indexed: 07/15/2023]
Abstract
We review comprehensive observations of electromagnetic ion cyclotron (EMIC) wave-driven energetic electron precipitation using data collected by the energetic electron detector on the Electron Losses and Fields InvestigatioN (ELFIN) mission, two polar-orbiting low-altitude spinning CubeSats, measuring 50-5000 keV electrons with good pitch-angle and energy resolution. EMIC wave-driven precipitation exhibits a distinct signature in energy-spectrograms of the precipitating-to-trapped flux ratio: peaks at >0.5 MeV which are abrupt (bursty) (lasting ∼17 s, or Δ L ∼ 0.56 ) with significant substructure (occasionally down to sub-second timescale). We attribute the bursty nature of the precipitation to the spatial extent and structuredness of the wave field at the equator. Multiple ELFIN passes over the same MLT sector allow us to study the spatial and temporal evolution of the EMIC wave - electron interaction region. Case studies employing conjugate ground-based or equatorial observations of the EMIC waves reveal that the energy of moderate and strong precipitation at ELFIN approximately agrees with theoretical expectations for cyclotron resonant interactions in a cold plasma. Using multiple years of ELFIN data uniformly distributed in local time, we assemble a statistical database of ∼50 events of strong EMIC wave-driven precipitation. Most reside at L ∼ 5 - 7 at dusk, while a smaller subset exists at L ∼ 8 - 12 at post-midnight. The energies of the peak-precipitation ratio and of the half-peak precipitation ratio (our proxy for the minimum resonance energy) exhibit an L -shell dependence in good agreement with theoretical estimates based on prior statistical observations of EMIC wave power spectra. The precipitation ratio's spectral shape for the most intense events has an exponential falloff away from the peak (i.e., on either side of ∼ 1.45 MeV). It too agrees well with quasi-linear diffusion theory based on prior statistics of wave spectra. It should be noted though that this diffusive treatment likely includes effects from nonlinear resonant interactions (especially at high energies) and nonresonant effects from sharp wave packet edges (at low energies). Sub-MeV electron precipitation observed concurrently with strong EMIC wave-driven >1 MeV precipitation has a spectral shape that is consistent with efficient pitch-angle scattering down to ∼ 200-300 keV by much less intense higher frequency EMIC waves at dusk (where such waves are most frequent). At ∼100 keV, whistler-mode chorus may be implicated in concurrent precipitation. These results confirm the critical role of EMIC waves in driving relativistic electron losses. Nonlinear effects may abound and require further investigation.
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Affiliation(s)
- V. Angelopoulos
- Earth, Planetary, and Space Sciences Department, and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, Los Angeles, CA 90095 USA
| | - X.-J. Zhang
- Earth, Planetary, and Space Sciences Department, and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, Los Angeles, CA 90095 USA
- Present Address: University of Texas at Dallas, Richardson, TX 75080 USA
| | - A. V. Artemyev
- Earth, Planetary, and Space Sciences Department, and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, Los Angeles, CA 90095 USA
| | | | - E. Tsai
- Earth, Planetary, and Space Sciences Department, and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, Los Angeles, CA 90095 USA
| | - C. Wilkins
- Earth, Planetary, and Space Sciences Department, and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, Los Angeles, CA 90095 USA
| | - A. Runov
- Earth, Planetary, and Space Sciences Department, and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, Los Angeles, CA 90095 USA
| | - J. Liu
- Earth, Planetary, and Space Sciences Department, and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, Los Angeles, CA 90095 USA
- Atmospheric and Oceanic Sciences Departments, University of California, Los Angeles, CA USA
| | - D. L. Turner
- Earth, Planetary, and Space Sciences Department, and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, Los Angeles, CA 90095 USA
- Present Address: Johns Hopkins University Applied Physics Laboratory, Laurel, Maryland USA
| | - W. Li
- Atmospheric and Oceanic Sciences Departments, University of California, Los Angeles, CA USA
| | - K. Khurana
- Earth, Planetary, and Space Sciences Department, and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, Los Angeles, CA 90095 USA
| | - R. E. Wirz
- Mechanical and Aerospace Engineering Department, Henry Samueli School of Engineering, University of California, Los Angeles, CA 90095 USA
- Present Address: School of Mechanical, Industrial, and Manufacturing Engineering, Oregon State University, Corvallis, OR 97331 USA
| | - V. A. Sergeev
- University of St. Petersburg, St. Petersburg, Russia
| | - X. Meng
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
| | - J. Wu
- Earth, Planetary, and Space Sciences Department, and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, Los Angeles, CA 90095 USA
| | - M. D. Hartinger
- Earth, Planetary, and Space Sciences Department, and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, Los Angeles, CA 90095 USA
- Space Science Institute, Boulder, CO 80301 USA
| | - T. Raita
- Sodankylä Geophysical Observatory, University of Oulu, Sodankylä, Finland
| | - Y. Shen
- Earth, Planetary, and Space Sciences Department, and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, Los Angeles, CA 90095 USA
| | - X. An
- Earth, Planetary, and Space Sciences Department, and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, Los Angeles, CA 90095 USA
| | - X. Shi
- Earth, Planetary, and Space Sciences Department, and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, Los Angeles, CA 90095 USA
| | - M. F. Bashir
- Earth, Planetary, and Space Sciences Department, and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, Los Angeles, CA 90095 USA
| | - X. Shen
- Department of Astronomy and Center for Space Physics, Boston University, Boston, MA USA
| | - L. Gan
- Department of Astronomy and Center for Space Physics, Boston University, Boston, MA USA
| | - M. Qin
- Department of Astronomy and Center for Space Physics, Boston University, Boston, MA USA
| | - L. Capannolo
- Department of Astronomy and Center for Space Physics, Boston University, Boston, MA USA
| | - Q. Ma
- Department of Astronomy and Center for Space Physics, Boston University, Boston, MA USA
| | - C. L. Russell
- Earth, Planetary, and Space Sciences Department, and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, Los Angeles, CA 90095 USA
| | - E. V. Masongsong
- Earth, Planetary, and Space Sciences Department, and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, Los Angeles, CA 90095 USA
| | - R. Caron
- Earth, Planetary, and Space Sciences Department, and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, Los Angeles, CA 90095 USA
| | - I. He
- Earth, Planetary, and Space Sciences Department, and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, Los Angeles, CA 90095 USA
- Materials Science and Engineering Department, Henry Samueli School of Engineering, University of California, Los Angeles, CA 90095 USA
| | - L. Iglesias
- Earth, Planetary, and Space Sciences Department, and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, Los Angeles, CA 90095 USA
- Present Address: Deloitte Consulting, New York, NY 10112 USA
| | - S. Jha
- Earth, Planetary, and Space Sciences Department, and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, Los Angeles, CA 90095 USA
- Computer Science Department, Henry Samueli School of Engineering, University of California, Los Angeles, CA 90095 USA
- Present Address: Microsoft, Redmond, WA 98052 USA
| | - J. King
- Earth, Planetary, and Space Sciences Department, and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, Los Angeles, CA 90095 USA
- Computer Science Department, Henry Samueli School of Engineering, University of California, Los Angeles, CA 90095 USA
| | - S. Kumar
- Earth, Planetary, and Space Sciences Department, and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, Los Angeles, CA 90095 USA
- Physics and Astronomy Department, University of California, Los Angeles, CA 90095 USA
- Present Address: Department of Astronomy and Astrophysics, The University of Chicago, Chicago, IL 60637 USA
| | - K. Le
- Earth, Planetary, and Space Sciences Department, and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, Los Angeles, CA 90095 USA
- Materials Science and Engineering Department, Henry Samueli School of Engineering, University of California, Los Angeles, CA 90095 USA
| | - J. Mao
- Earth, Planetary, and Space Sciences Department, and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, Los Angeles, CA 90095 USA
- Computer Science Department, Henry Samueli School of Engineering, University of California, Los Angeles, CA 90095 USA
- Present Address: Raybeam, Inc., Mountain View, CA 94041 USA
| | - A. McDermott
- Earth, Planetary, and Space Sciences Department, and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, Los Angeles, CA 90095 USA
- Mechanical and Aerospace Engineering Department, Henry Samueli School of Engineering, University of California, Los Angeles, CA 90095 USA
| | - K. Nguyen
- Earth, Planetary, and Space Sciences Department, and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, Los Angeles, CA 90095 USA
- Mechanical and Aerospace Engineering Department, Henry Samueli School of Engineering, University of California, Los Angeles, CA 90095 USA
- Present Address: SpaceX, Hawthorne, CA 90250 USA
| | - A. Norris
- Earth, Planetary, and Space Sciences Department, and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, Los Angeles, CA 90095 USA
| | - A. Palla
- Earth, Planetary, and Space Sciences Department, and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, Los Angeles, CA 90095 USA
- Computer Science Department, Henry Samueli School of Engineering, University of California, Los Angeles, CA 90095 USA
- Present Address: Reliable Robotics Corporation, Mountain View, CA 94043 USA
| | - A. Roosnovo
- Earth, Planetary, and Space Sciences Department, and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, Los Angeles, CA 90095 USA
- Physics and Astronomy Department, University of California, Los Angeles, CA 90095 USA
- Present Address: Los Alamos National Laboratory, Los Alamos, NM 87545 USA
| | - J. Tam
- Earth, Planetary, and Space Sciences Department, and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, Los Angeles, CA 90095 USA
- Mechanical and Aerospace Engineering Department, Henry Samueli School of Engineering, University of California, Los Angeles, CA 90095 USA
| | - E. Xie
- Earth, Planetary, and Space Sciences Department, and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, Los Angeles, CA 90095 USA
- Present Address: Deloitte Consulting, New York, NY 10112 USA
- Computer Science Department, Henry Samueli School of Engineering, University of California, Los Angeles, CA 90095 USA
| | - R. C. Yap
- Earth, Planetary, and Space Sciences Department, and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, Los Angeles, CA 90095 USA
- Mathematics Department, University of California, Los Angeles, CA 90095 USA
- Present Address: Planet Labs, PBC, San Francisco, CA 94107 USA
| | - S. Ye
- Earth, Planetary, and Space Sciences Department, and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, Los Angeles, CA 90095 USA
- Mechanical and Aerospace Engineering Department, Henry Samueli School of Engineering, University of California, Los Angeles, CA 90095 USA
| | - C. Young
- Earth, Planetary, and Space Sciences Department, and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, Los Angeles, CA 90095 USA
- Computer Science Department, Henry Samueli School of Engineering, University of California, Los Angeles, CA 90095 USA
- Present Address: Microsoft, Redmond, WA 98052 USA
| | - L. A. Adair
- Earth, Planetary, and Space Sciences Department, and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, Los Angeles, CA 90095 USA
- Physics and Astronomy Department, University of California, Los Angeles, CA 90095 USA
- Present Address: KSAT, Inc., Denver, CO 80231 USA
| | - C. Shaffer
- Earth, Planetary, and Space Sciences Department, and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, Los Angeles, CA 90095 USA
- Mechanical and Aerospace Engineering Department, Henry Samueli School of Engineering, University of California, Los Angeles, CA 90095 USA
- Present Address: Tyvak Nano-Satellite Systems, Inc., Irvine, CA 92618 USA
| | - M. Chung
- Earth, Planetary, and Space Sciences Department, and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, Los Angeles, CA 90095 USA
- Present Address: Northrop Grumman Aerospace Systems, Redondo Beach, CA 90278 USA
| | - P. Cruce
- Earth, Planetary, and Space Sciences Department, and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, Los Angeles, CA 90095 USA
- Present Address: Apple, Cupertino, CA 95014 USA
| | - M. Lawson
- Earth, Planetary, and Space Sciences Department, and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, Los Angeles, CA 90095 USA
| | - D. Leneman
- Earth, Planetary, and Space Sciences Department, and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, Los Angeles, CA 90095 USA
| | - M. Allen
- Earth, Planetary, and Space Sciences Department, and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, Los Angeles, CA 90095 USA
- Mechanical and Aerospace Engineering Department, Henry Samueli School of Engineering, University of California, Los Angeles, CA 90095 USA
- Present Address: Zipline International, South San Francisco, CA 94080 USA
| | - M. Anderson
- Earth, Planetary, and Space Sciences Department, and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, Los Angeles, CA 90095 USA
- Mathematics Department, University of California, Los Angeles, CA 90095 USA
- Present Address: Lucid Motors, Newark, CA 94560 USA
| | - M. Arreola-Zamora
- Earth, Planetary, and Space Sciences Department, and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, Los Angeles, CA 90095 USA
- Present Address: Northrop Grumman Aerospace Systems, Redondo Beach, CA 90278 USA
| | - J. Artinger
- Earth, Planetary, and Space Sciences Department, and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, Los Angeles, CA 90095 USA
- Physics and Astronomy Department, University of California, Los Angeles, CA 90095 USA
- Present Address: College of Engineering and Computer Science, California State University, Fullerton, Fullerton, CA 92831 USA
| | - J. Asher
- Earth, Planetary, and Space Sciences Department, and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, Los Angeles, CA 90095 USA
- Mechanical and Aerospace Engineering Department, Henry Samueli School of Engineering, University of California, Los Angeles, CA 90095 USA
- Present Address: The Aerospace Corporation, El Segundo, CA 90245 USA
| | - D. Branchevsky
- Earth, Planetary, and Space Sciences Department, and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, Los Angeles, CA 90095 USA
- Present Address: The Aerospace Corporation, El Segundo, CA 90245 USA
- Electrical and Computer Engineering Department, Henry Samueli School of Engineering, University of California, Los Angeles, CA 90095 USA
| | - M. Cliffe
- Earth, Planetary, and Space Sciences Department, and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, Los Angeles, CA 90095 USA
- Present Address: SpaceX, Hawthorne, CA 90250 USA
- Electrical and Computer Engineering Department, Henry Samueli School of Engineering, University of California, Los Angeles, CA 90095 USA
| | - K. Colton
- Earth, Planetary, and Space Sciences Department, and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, Los Angeles, CA 90095 USA
- Mathematics Department, University of California, Los Angeles, CA 90095 USA
- Present Address: Planet Labs, PBC, San Francisco, CA 94107 USA
| | - C. Costello
- Earth, Planetary, and Space Sciences Department, and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, Los Angeles, CA 90095 USA
- Computer Science Department, Henry Samueli School of Engineering, University of California, Los Angeles, CA 90095 USA
- Present Address: Heliogen, Pasadena, CA 91103 USA
| | - D. Depe
- Earth, Planetary, and Space Sciences Department, and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, Los Angeles, CA 90095 USA
- Electrical and Computer Engineering Department, Henry Samueli School of Engineering, University of California, Los Angeles, CA 90095 USA
- Present Address: Argo AI, LLC, Pittsburgh, PA 15222 USA
| | - B. W. Domae
- Earth, Planetary, and Space Sciences Department, and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, Los Angeles, CA 90095 USA
- Electrical and Computer Engineering Department, Henry Samueli School of Engineering, University of California, Los Angeles, CA 90095 USA
| | - S. Eldin
- Earth, Planetary, and Space Sciences Department, and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, Los Angeles, CA 90095 USA
- Present Address: Microsoft, Redmond, WA 98052 USA
- Electrical and Computer Engineering Department, Henry Samueli School of Engineering, University of California, Los Angeles, CA 90095 USA
| | - L. Fitzgibbon
- Earth, Planetary, and Space Sciences Department, and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, Los Angeles, CA 90095 USA
- Physics and Astronomy Department, University of California, Los Angeles, CA 90095 USA
- Present Address: Terran Orbital, Irvine, CA 92618 USA
| | - A. Flemming
- Earth, Planetary, and Space Sciences Department, and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, Los Angeles, CA 90095 USA
- Mechanical and Aerospace Engineering Department, Henry Samueli School of Engineering, University of California, Los Angeles, CA 90095 USA
- Present Address: Northrop Grumman Aerospace Systems, Redondo Beach, CA 90278 USA
| | - D. M. Frederick
- Earth, Planetary, and Space Sciences Department, and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, Los Angeles, CA 90095 USA
- Mechanical and Aerospace Engineering Department, Henry Samueli School of Engineering, University of California, Los Angeles, CA 90095 USA
- Present Address: Millenium Space Systems, El Segundo, CA 90245 USA
| | - A. Gilbert
- Earth, Planetary, and Space Sciences Department, and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, Los Angeles, CA 90095 USA
- Electrical and Computer Engineering Department, Henry Samueli School of Engineering, University of California, Los Angeles, CA 90095 USA
- Present Address: Department of Electrical Engineering, Stanford University, Stanford, CA 94305 USA
| | - B. Hesford
- Earth, Planetary, and Space Sciences Department, and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, Los Angeles, CA 90095 USA
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
- Electrical and Computer Engineering Department, Henry Samueli School of Engineering, University of California, Los Angeles, CA 90095 USA
| | - R. Krieger
- Earth, Planetary, and Space Sciences Department, and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, Los Angeles, CA 90095 USA
- Materials Science and Engineering Department, Henry Samueli School of Engineering, University of California, Los Angeles, CA 90095 USA
- Present Address: Mercedes-Benz Research and Development North America, Long Beach, CA 90810 USA
| | - K. Lian
- Earth, Planetary, and Space Sciences Department, and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, Los Angeles, CA 90095 USA
- Mechanical and Aerospace Engineering Department, Henry Samueli School of Engineering, University of California, Los Angeles, CA 90095 USA
- Present Address: The Aerospace Corporation, El Segundo, CA 90245 USA
| | - E. McKinney
- Earth, Planetary, and Space Sciences Department, and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, Los Angeles, CA 90095 USA
- Present Address: Geosyntec Consultants, Inc., Costa Mesa, CA 92626 USA
| | - J. P. Miller
- Earth, Planetary, and Space Sciences Department, and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, Los Angeles, CA 90095 USA
- Computer Science Department, Henry Samueli School of Engineering, University of California, Los Angeles, CA 90095 USA
- Present Address: Juniper Networks Sunnyvale, California, 94089 USA
| | - C. Pedersen
- Earth, Planetary, and Space Sciences Department, and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, Los Angeles, CA 90095 USA
- Mechanical and Aerospace Engineering Department, Henry Samueli School of Engineering, University of California, Los Angeles, CA 90095 USA
| | - Z. Qu
- Earth, Planetary, and Space Sciences Department, and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, Los Angeles, CA 90095 USA
- Mechanical and Aerospace Engineering Department, Henry Samueli School of Engineering, University of California, Los Angeles, CA 90095 USA
- Present Address: Niantic Inc., San Francisco, CA 94111 USA
| | - R. Rozario
- Earth, Planetary, and Space Sciences Department, and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, Los Angeles, CA 90095 USA
- Mechanical and Aerospace Engineering Department, Henry Samueli School of Engineering, University of California, Los Angeles, CA 90095 USA
- Present Address: SpaceX, Hawthorne, CA 90250 USA
| | - M. Rubly
- Earth, Planetary, and Space Sciences Department, and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, Los Angeles, CA 90095 USA
- Mechanical and Aerospace Engineering Department, Henry Samueli School of Engineering, University of California, Los Angeles, CA 90095 USA
- Present Address: Teledyne Scientific and Imaging, Thousand Oaks, CA 91360 USA
| | - R. Seaton
- Earth, Planetary, and Space Sciences Department, and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, Los Angeles, CA 90095 USA
- Mechanical and Aerospace Engineering Department, Henry Samueli School of Engineering, University of California, Los Angeles, CA 90095 USA
| | - A. Subramanian
- Earth, Planetary, and Space Sciences Department, and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, Los Angeles, CA 90095 USA
- Present Address: Northrop Grumman Aerospace Systems, Redondo Beach, CA 90278 USA
- Electrical and Computer Engineering Department, Henry Samueli School of Engineering, University of California, Los Angeles, CA 90095 USA
| | - S. R. Sundin
- Earth, Planetary, and Space Sciences Department, and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, Los Angeles, CA 90095 USA
- Mechanical and Aerospace Engineering Department, Henry Samueli School of Engineering, University of California, Los Angeles, CA 90095 USA
- Present Address: Naval Surface Warfare Center Corona Division, Norco, CA 92860 USA
| | - A. Tan
- Earth, Planetary, and Space Sciences Department, and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, Los Angeles, CA 90095 USA
- Electrical and Computer Engineering Department, Henry Samueli School of Engineering, University of California, Los Angeles, CA 90095 USA
- Present Address: Epirus Inc., Torrance, CA 90501 USA
| | - D. Thomlinson
- Earth, Planetary, and Space Sciences Department, and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, Los Angeles, CA 90095 USA
- Mechanical and Aerospace Engineering Department, Henry Samueli School of Engineering, University of California, Los Angeles, CA 90095 USA
- Present Address: The Aerospace Corporation, El Segundo, CA 90245 USA
| | - W. Turner
- Earth, Planetary, and Space Sciences Department, and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, Los Angeles, CA 90095 USA
- Physics and Astronomy Department, University of California, Los Angeles, CA 90095 USA
- Present Address: Department of Astronomy, Ohio State University, Columbus, OH 43210 USA
| | - G. Wing
- Earth, Planetary, and Space Sciences Department, and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, Los Angeles, CA 90095 USA
- Computer Science Department, Henry Samueli School of Engineering, University of California, Los Angeles, CA 90095 USA
- Present Address: Amazon, Seattle, WA 98109 USA
| | - C. Wong
- Earth, Planetary, and Space Sciences Department, and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, Los Angeles, CA 90095 USA
- Physics and Astronomy Department, University of California, Los Angeles, CA 90095 USA
- Present Address: Department of Radiology, University of California, San Francisco, San Francisco, CA 94143 USA
| | - A. Zarifian
- Earth, Planetary, and Space Sciences Department, and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, Los Angeles, CA 90095 USA
- Mechanical and Aerospace Engineering Department, Henry Samueli School of Engineering, University of California, Los Angeles, CA 90095 USA
- Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 USA
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4
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Rogers AJ, Farrugia CJ, Torbert RB, Rogers TJ. Applying Magnetic Curvature to MMS Data to Identify Thin Current Sheets Relative to Tail Reconnection. JOURNAL OF GEOPHYSICAL RESEARCH. SPACE PHYSICS 2023; 128:e2022JA030577. [PMID: 37035416 PMCID: PMC10078146 DOI: 10.1029/2022ja030577] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Revised: 12/10/2022] [Accepted: 12/30/2022] [Indexed: 06/19/2023]
Abstract
Thin current sheets (TCSs) have been postulated to be a necessary precondition for reconnection onset. Magnetic reconnection X-lines in the magnetotail have been observed to be more common duskward of midnight. We take advantage of the MMS tetrahedral formation during the 2017-2020 MMS tail seasons to calculate the thickness of the cross-tail neutral sheet relative to ion gyroradius. While a similar technique was applied to Cluster data, current sheet thickness over a broader range of radial distances has not been robustly explored before this study. We compare our analysis to recent theories regarding mechanisms of tail current sheet thinning and to recent simulations. We find MMS spent more than twice as long in ion-scale TCSs in the pre-midnight sector than post-midnight, despite nearly even plasma sheet dwell time. The dawn-dusk asymmetry in the distribution of Ion Diffusion Regions, as previously reported in relation to regions of TCSs, is also analyzed.
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Affiliation(s)
- A. J. Rogers
- Space Science CenterUniversity of New HampshireDurhamNHUSA
- Los Alamos National LaboratoryLos AlamosNMUSA
| | - C. J. Farrugia
- Space Science CenterUniversity of New HampshireDurhamNHUSA
| | - R. B. Torbert
- Space Science CenterUniversity of New HampshireDurhamNHUSA
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5
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Sun W, Turner DL, Zhang Q, Wang S, Egedal J, Leonard T, Slavin JA, Hu Q, Cohen IJ, Genestreti K, Poh G, Gershman DJ, Smith A, Le G, Nakamura R, Giles BL, Ergun RE, Burch JL. Properties and Acceleration Mechanisms of Electrons Up To 200 keV Associated With a Flux Rope Pair and Reconnection X-Lines Around It in Earth's Plasma Sheet. JOURNAL OF GEOPHYSICAL RESEARCH. SPACE PHYSICS 2022; 127:e2022JA030721. [PMID: 37032657 PMCID: PMC10078532 DOI: 10.1029/2022ja030721] [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: 06/06/2022] [Revised: 10/26/2022] [Accepted: 12/02/2022] [Indexed: 06/19/2023]
Abstract
The properties and acceleration mechanisms of electrons (<200 keV) associated with a pair of tailward traveling flux ropes and accompanied reconnection X-lines in Earth's plasma sheet are investigated with MMS measurements. Energetic electrons are enhanced on both boundaries and core of the flux ropes. The power-law spectra of energetic electrons near the X-lines and in flux ropes are harder than those on flux rope boundaries. Theoretical calculations show that the highest energy of adiabatic electrons is a few keV around the X-lines, tens of keV immediately downstream of the X-lines, hundreds of keV on the flux rope boundaries, and a few MeV in the flux rope cores. The X-lines cause strong energy dissipation, which may generate the energetic electron beams around them. The enhanced electron parallel temperature can be caused by the curvature-driven Fermi acceleration and the parallel electric potential. Betatron acceleration due to the magnetic field compression is strong on flux rope boundaries, which enhances energetic electrons in the perpendicular direction. Electrons can be trapped between the flux rope pair due to mirror force and parallel electric potential. Electrostatic structures in the flux rope cores correspond to potential drops up to half of the electron temperature. The energetic electrons and the electron distribution functions in the flux rope cores are suggested to be transported from other dawn-dusk directions, which is a 3-dimensional effect. The acceleration and deceleration of the Betatron and Fermi processes appear alternately indicating that the magnetic field and plasma are turbulent around the flux ropes.
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Affiliation(s)
- Weijie Sun
- Department of Climate and Space Sciences and EngineeringUniversity of MichiganAnn ArborMIUSA
| | - Drew L. Turner
- Space Exploration SectorJohns Hopkins Applied Physics LaboratoryLaurelMDUSA
| | - Qile Zhang
- Los Alamos National LaboratoryLos AlamosNMUSA
| | - Shan Wang
- Department of AstronomyUniversity of MarylandCollege ParkMDUSA
| | - Jan Egedal
- Department of PhysicsUniversity of Wisconsin‐MadisonMadisonWIUSA
| | - Trevor Leonard
- Laboratory for Atmospheric and Space PhysicsUniversity of Colorado BoulderBoulderCOUSA
| | - James A. Slavin
- Department of Climate and Space Sciences and EngineeringUniversity of MichiganAnn ArborMIUSA
| | - Qiang Hu
- Department of Space ScienceCenter for Space Plasma and Aeronomic ResearchThe University of Alabama in HuntsvilleHuntsvilleALUSA
| | - Ian J. Cohen
- Space Exploration SectorJohns Hopkins Applied Physics LaboratoryLaurelMDUSA
| | | | - Gangkai Poh
- NASA Goddard Space Flight CenterGreenbeltMDUSA
- Center for Research and Exploration in Space Sciences and Technology IICatholic University of AmericaWashingtonDCUSA
| | | | - Andrew Smith
- Mullard Space Science LaboratoryUniversity College LondonSurreyUK
- Department of Mathematics, Physics and Electrical EngineeringNorthumbria UniversityNewcastle Upon TyneUK
| | - Guan Le
- NASA Goddard Space Flight CenterGreenbeltMDUSA
| | - Rumi Nakamura
- Space Research InstituteAustrian Academy of SciencesGrazAustria
| | | | - Robert E. Ergun
- Department of Astrophysical and Planetary SciencesUniversity of Colorado BoulderBoulderCOUSA
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6
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Lukin AS, Artemyev AV, Vainchtein DL, Petrukovich AA. Regimes of ion dynamics in current sheets: The machine learning approach. Phys Rev E 2022; 106:065205. [PMID: 36671165 DOI: 10.1103/physreve.106.065205] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Accepted: 11/28/2022] [Indexed: 12/24/2022]
Abstract
Current sheets are spatially localized almost-one-dimensional (1D) structures with intense plasma currents. They play a key role in storing the magnetic field energy and they separate different plasma populations in planetary magnetospheres, the solar wind, and the solar corona. Current sheets are primary regions for the magnetic field line reconnection responsible for plasma heating and charged particle acceleration. One of the most interesting and widely observed types of 1D current sheets is the rotational discontinuity, which can be force-free or include plasma compression. Theoretical models of such 1D current sheets are based on the assumption of adiabatic motion of ions, i.e., ion adiabatic invariants are conserved. We focus on three current sheet configurations, widely observed in the Earth magnetopause and magnetotail and in the near-Earth solar wind. The magnetic field in such current sheets is supported by currents carried by transient ions, which exist only when there is a sufficient number of invariants. In this paper, we apply a machine learning approach, AI Poincaré, to determine parametrical domains where adiabatic invariants are conserved. For all three current sheet configurations, these domains are quite narrow and do not cover the entire parametrical range of observed current sheets. We discuss possible interpretation of obtained results indicating that 1D current sheets are dynamical rather than static plasma equilibria.
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Affiliation(s)
- A S Lukin
- Space Research Institute RAS, Moscow 117997, Russia.,Faculty of Physics, National Research University Higher School of Economics, Moscow 101000, Russia
| | - A V Artemyev
- Space Research Institute RAS, Moscow 117997, Russia.,Institute of Geophysics and Planetary Physics, University of California, Los Angeles, California 90095, USA
| | - D L Vainchtein
- Space Research Institute RAS, Moscow 117997, Russia.,Nyheim Plasma Institute, Drexel University, Camden, New Jersey 08103, USA
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7
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Ulysses Flyby in the Heliosphere: Comparison of the Solar Wind Model with Observational Data. UNIVERSE 2022. [DOI: 10.3390/universe8060324] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
A model capable of reproducing a set of solar wind parameters along the virtual spacecraft orbit out of an ecliptic plane has been developed. In the framework of a quasi-stationary axisymmetric self-consistent MHD model the spatial distributions of magnetic field and plasma characteristics at distances from 20 to 1200 Solar radii at almost all solar latitudes could be obtained and analyzed. This model takes into account the Sun’s magnetic field evolution during the solar cycle, when the dominant dipole magnetic field is replaced by the quadrupole one. Self-consistent solutions for solar wind characteristics were obtained, depending on the phase of the solar cycle. To verify the model, its results are compared with the observed characteristics of solar wind along the Ulysses trajectory during its flyby around the Sun from 1990 to 2009. It is shown that the results of numerical simulation are generally consistent with the observational data obtained by the Ulysses spacecraft. A comparison of the model and experimental data confirms that the model can adequately describe the solar wind parameters and can be used for heliospheric studies at different phases of the solar activity cycle, as well as in a wide range of latitudinal angles and distances to the Sun.
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8
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Muraviev A, Bashinov A, Efimenko E, Gonoskov A, Meyerov I, Sergeev A. Particle dynamics governed by radiation losses in extreme-field current sheets. Phys Rev E 2021; 104:065201. [PMID: 35030924 DOI: 10.1103/physreve.104.065201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Accepted: 11/05/2021] [Indexed: 11/07/2022]
Abstract
Particles moving in current sheets under extreme conditions, such as those in the vicinity of pulsars or those predicted on upcoming multipetawatt laser facilities, may be subject to significant radiation losses. We present an analysis of particle motion in model fields of a relativistic neutral electron-positron current sheet in the case when radiative effects must be accounted for. In the Landau-Lifshitz radiation reaction force model, when quantum effects are negligible, an analytical solution for particle trajectories is derived. Based on this solution, for the case when quantum effects are significant an averaged quantum solution in the semiclassical approach is obtained. The applicability region of the solutions is determined and analytical trajectories are found to be in good agreement with those of numerical simulations which account for radiative effects. Based on these results we demonstrate that radiation reaction itself can provide a mechanism of pinching even within a given field consideration.
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Affiliation(s)
- A Muraviev
- Institute of Applied Physics of the Russian Academy of Sciences, Nizhny Novgorod 603950, Russia
| | - A Bashinov
- Institute of Applied Physics of the Russian Academy of Sciences, Nizhny Novgorod 603950, Russia
| | - E Efimenko
- Institute of Applied Physics of the Russian Academy of Sciences, Nizhny Novgorod 603950, Russia
| | - A Gonoskov
- Department of Physics, University of Gothenburg, SE-41296 Gothenburg, Sweden.,Lobachevsky State University of Nizhni Novgorod, Nizhny Novgorod 603950, Russia
| | - I Meyerov
- Lobachevsky State University of Nizhni Novgorod, Nizhny Novgorod 603950, Russia
| | - A Sergeev
- Institute of Applied Physics of the Russian Academy of Sciences, Nizhny Novgorod 603950, Russia
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9
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Malara F, Perri S, Zimbardo G. Charged-particle chaotic dynamics in rotational discontinuities. Phys Rev E 2021; 104:025208. [PMID: 34525548 DOI: 10.1103/physreve.104.025208] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Accepted: 08/02/2021] [Indexed: 11/07/2022]
Abstract
The interplanetary plasma is characterized by a high level of complexity over a broad range of spatial scales. Spacecraft have detected a large variety of embedded structures that have been identified as discontinuities in the magnetic field vector. They can be either generated within the solar corona and advected by the plasma flow or locally generated as a result of the turbulent cascade of the solar wind turbulence. Since magnetic field fluctuations and structures influence the energetic particle propagation, here we set up a numerical model to study the interaction between charged particles and an ideal magnetohydrodynamics rotational discontinuity. This interaction is strongly influenced by the model parameters, such as the rotation angle of the discontinuity, the orientation of the mean-field direction with respect to the normal to the discontinuity direction, the initial particle pitch angle, and the initial particle gyrophase. Numerical results clearly show that the motion of particles crossing the discontinuity is extremely complex and highly sensitive to the initial conditions of the system, with transitions to a chaotic behavior. We find that particles can be temporarily trapped in rotational discontinuity and that the trapping times have a nearly power-law distribution. Also, the separatrix in the initial conditions phase space between crossing and noncrossing trajectories has a fractal structure. Implications for energetic particle propagation in space plasmas are discussed.
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Affiliation(s)
- Francesco Malara
- Dipartimento di Fisica, Università della Calabria, Ponte P. Bucci, cubo 31 C, 87036 Rende (CS), Italy
| | - Silvia Perri
- Dipartimento di Fisica, Università della Calabria, Ponte P. Bucci, cubo 31 C, 87036 Rende (CS), Italy
| | - Gaetano Zimbardo
- Dipartimento di Fisica, Università della Calabria, Ponte P. Bucci, cubo 31 C, 87036 Rende (CS), Italy
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10
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Collisionless relaxation of a disequilibrated current sheet and implications for bifurcated structures. Nat Commun 2021; 12:3774. [PMID: 34145266 PMCID: PMC8213726 DOI: 10.1038/s41467-021-24006-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Accepted: 05/28/2021] [Indexed: 11/17/2022] Open
Abstract
Current sheets are ubiquitous plasma structures that play the crucial role of being energy sources for various magnetic phenomena. Although a plethora of current sheet equilibrium solutions have been found, the collisionless process through which a disequilibrated current sheet relaxes or equilibrates remains largely unknown. Here we show, through analyses of phase-space distributions of single-particle orbit classes and particle-in-cell simulations, that collisionless transitions among the orbit classes are responsible for this process. Bifurcated current sheets, which are readily observed in geospace but whose origins remain controversial, are shown to naturally arise from the equilibration process and thus are likely to be the underlying structures in various phenomena; comparisons of spacecraft observations to particle-in-cell simulations support this fact. The bearing of this result on previous explanations of bifurcated structures is also discussed. Bifurcated current sheets are a recurring feature in magnetized space plasmas. Here the authors explain the emergence of bifurcated structures by natural redistributions of single-particle orbits during the collisionless relaxation process of a disequilibrated current sheet.
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11
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Bouazza, F., Hassikou, R., Amallah, L., Ennadir, J., Khedid, K.. Evaluation of antibacterial activity of essential oils extracted from Thymus satureioides and Mentha pulegium against antibiotic resistance bacteria from raw sheep milk. MALAYSIAN JOURNAL OF MICROBIOLOGY 2021. [DOI: 10.1029/2010ja016000] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
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12
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Artemyev AV, Neishtadt AI, Vasiliev AA, Angelopoulos V, Vinogradov AA, Zelenyi LM. Superfast ion scattering by solar wind discontinuities. Phys Rev E 2020; 102:033201. [PMID: 33075989 DOI: 10.1103/physreve.102.033201] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Accepted: 08/20/2020] [Indexed: 11/07/2022]
Abstract
Large-amplitude fluctuations of the solar wind magnetic field can scatter energetic ions. One of the main contributions to these fluctuations is provided by solar wind discontinuities, i.e., rapid rotations of the magnetic field. This study shows that the internal configuration of such discontinuities plays a crucial role in energetic ion scattering in pitch angles. Kinetic-scale discontinuities accomplish very fast ion pitch-angle scattering. The main mechanism of such pitch-angle scattering is the adiabatic invariant destruction due to separatrix crossings in the phase space. We demonstrate that efficiency of this scattering does not depend on the magnetic field component across the discontinuity surface, i.e., both rotational and almost tangential discontinuities scatter energetic ions with the same efficiency. We also examine how the strong scattering effect depends on the deviations of the discontinuity magnetic field from the force-free one.
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Affiliation(s)
- A V Artemyev
- Institute of Geophysics and Planetary Physics, University of California, Los Angeles, California, USA.,Space Research Institute RAS, Moscow, Russia
| | - A I Neishtadt
- Space Research Institute RAS, Moscow, Russia.,Department of Mathematical Sciences, Loughborough University, Loughborough LE11 3TU, United Kingdom
| | | | - V Angelopoulos
- Institute of Geophysics and Planetary Physics, University of California, Los Angeles, California, USA
| | | | - L M Zelenyi
- Space Research Institute RAS, Moscow, Russia.,Moscow Institute of Physics and Technology (State University), 141700, Dolgoprudnyi, Moscow oblast, Russia
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13
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Angelopoulos V, Tsai E, Bingley L, Shaffer C, Turner DL, Runov A, Li W, Liu J, Artemyev AV, Zhang XJ, Strangeway RJ, Wirz RE, Shprits YY, Sergeev VA, Caron RP, Chung M, Cruce P, Greer W, Grimes E, Hector K, Lawson MJ, Leneman D, Masongsong EV, Russell CL, Wilkins C, Hinkley D, Blake JB, Adair N, Allen M, Anderson M, Arreola-Zamora M, Artinger J, Asher J, Branchevsky D, Capitelli MR, Castro R, Chao G, Chung N, Cliffe M, Colton K, Costello C, Depe D, Domae BW, Eldin S, Fitzgibbon L, Flemming A, Fox I, Frederick DM, Gilbert A, Gildemeister A, Gonzalez A, Hesford B, Jha S, Kang N, King J, Krieger R, Lian K, Mao J, McKinney E, Miller JP, Norris A, Nuesca M, Palla A, Park ESY, Pedersen CE, Qu Z, Rozario R, Rye E, Seaton R, Subramanian A, Sundin SR, Tan A, Turner W, Villegas AJ, Wasden M, Wing G, Wong C, Xie E, Yamamoto S, Yap R, Zarifian A, Zhang GY. The ELFIN Mission. SPACE SCIENCE REVIEWS 2020; 216:103. [PMID: 32831412 PMCID: PMC7413588 DOI: 10.1007/s11214-020-00721-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Accepted: 07/09/2020] [Indexed: 06/11/2023]
Abstract
The Electron Loss and Fields Investigation with a Spatio-Temporal Ambiguity-Resolving option (ELFIN-STAR, or heretoforth simply: ELFIN) mission comprises two identical 3-Unit (3U) CubeSats on a polar (∼93∘ inclination), nearly circular, low-Earth (∼450 km altitude) orbit. Launched on September 15, 2018, ELFIN is expected to have a >2.5 year lifetime. Its primary science objective is to resolve the mechanism of storm-time relativistic electron precipitation, for which electromagnetic ion cyclotron (EMIC) waves are a prime candidate. From its ionospheric vantage point, ELFIN uses its unique pitch-angle-resolving capability to determine whether measured relativistic electron pitch-angle and energy spectra within the loss cone bear the characteristic signatures of scattering by EMIC waves or whether such scattering may be due to other processes. Pairing identical ELFIN satellites with slowly-variable along-track separation allows disambiguation of spatial and temporal evolution of the precipitation over minutes-to-tens-of-minutes timescales, faster than the orbit period of a single low-altitude satellite (Torbit ∼ 90 min). Each satellite carries an energetic particle detector for electrons (EPDE) that measures 50 keV to 5 MeV electrons with Δ E/E < 40% and a fluxgate magnetometer (FGM) on a ∼72 cm boom that measures magnetic field waves (e.g., EMIC waves) in the range from DC to 5 Hz Nyquist (nominally) with <0.3 nT/sqrt(Hz) noise at 1 Hz. The spinning satellites (Tspin ∼ 3 s) are equipped with magnetorquers (air coils) that permit spin-up or -down and reorientation maneuvers. Using those, the spin axis is placed normal to the orbit plane (nominally), allowing full pitch-angle resolution twice per spin. An energetic particle detector for ions (EPDI) measures 250 keV - 5 MeV ions, addressing secondary science. Funded initially by CalSpace and the University Nanosat Program, ELFIN was selected for flight with joint support from NSF and NASA between 2014 and 2018 and launched by the ELaNa XVIII program on a Delta II rocket (with IceSatII as the primary). Mission operations are currently funded by NASA. Working under experienced UCLA mentors, with advice from The Aerospace Corporation and NASA personnel, more than 250 undergraduates have matured the ELFIN implementation strategy; developed the instruments, satellite, and ground systems and operate the two satellites. ELFIN's already high potential for cutting-edge science return is compounded by concurrent equatorial Heliophysics missions (THEMIS, Arase, Van Allen Probes, MMS) and ground stations. ELFIN's integrated data analysis approach, rapid dissemination strategies via the SPace Environment Data Analysis System (SPEDAS), and data coordination with the Heliophysics/Geospace System Observatory (H/GSO) optimize science yield, enabling the widest community benefits. Several storm-time events have already been captured and are presented herein to demonstrate ELFIN's data analysis methods and potential. These form the basis of on-going studies to resolve the primary mission science objective. Broad energy precipitation events, precipitation bands, and microbursts, clearly seen both at dawn and dusk, extend from tens of keV to >1 MeV. This broad energy range of precipitation indicates that multiple waves are providing scattering concurrently. Many observed events show significant backscattered fluxes, which in the past were hard to resolve by equatorial spacecraft or non-pitch-angle-resolving ionospheric missions. These observations suggest that the ionosphere plays a significant role in modifying magnetospheric electron fluxes and wave-particle interactions. Routine data captures starting in February 2020 and lasting for at least another year, approximately the remainder of the mission lifetime, are expected to provide a very rich dataset to address questions even beyond the primary mission science objective.
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Affiliation(s)
- V Angelopoulos
- Earth, Planetary, and Space Sciences Department, University of California, Los Angeles, CA 90095 USA
- Institute of Geophysics and Planetary Physics, University of California, San Diego, CA USA
| | - E Tsai
- Earth, Planetary, and Space Sciences Department, University of California, Los Angeles, CA 90095 USA
- Institute of Geophysics and Planetary Physics, University of California, San Diego, CA USA
| | - L Bingley
- Earth, Planetary, and Space Sciences Department, University of California, Los Angeles, CA 90095 USA
- Institute of Geophysics and Planetary Physics, University of California, San Diego, CA USA
| | - C Shaffer
- Earth, Planetary, and Space Sciences Department, University of California, Los Angeles, CA 90095 USA
- Present Address: Tyvak Nano-Satellite Systems, Inc., Irvine, CA 92618 USA
| | - D L Turner
- Earth, Planetary, and Space Sciences Department, University of California, Los Angeles, CA 90095 USA
- Present Address: Johns Hopkins University Applied Physics Laboratory, Laurel, MD 20723 USA
| | - A Runov
- Earth, Planetary, and Space Sciences Department, University of California, Los Angeles, CA 90095 USA
- Institute of Geophysics and Planetary Physics, University of California, San Diego, CA USA
| | - W Li
- Earth, Planetary, and Space Sciences Department, University of California, Los Angeles, CA 90095 USA
- Institute of Geophysics and Planetary Physics, University of California, San Diego, CA USA
- Present Address: Department of Astronomy and Center for Space Physics, Boston University, Boston, MA 02215 USA
| | - J Liu
- Earth, Planetary, and Space Sciences Department, University of California, Los Angeles, CA 90095 USA
- Institute of Geophysics and Planetary Physics, University of California, San Diego, CA USA
| | - A V Artemyev
- Earth, Planetary, and Space Sciences Department, University of California, Los Angeles, CA 90095 USA
- Institute of Geophysics and Planetary Physics, University of California, San Diego, CA USA
| | - X-J Zhang
- Earth, Planetary, and Space Sciences Department, University of California, Los Angeles, CA 90095 USA
- Institute of Geophysics and Planetary Physics, University of California, San Diego, CA USA
| | - R J Strangeway
- Earth, Planetary, and Space Sciences Department, University of California, Los Angeles, CA 90095 USA
- Institute of Geophysics and Planetary Physics, University of California, San Diego, CA USA
| | - R E Wirz
- Mechanical and Aerospace Engineering Department, Henry Samueli School of Engineering, University of California, Los Angeles, CA 90095 USA
| | - Y Y Shprits
- Earth, Planetary, and Space Sciences Department, University of California, Los Angeles, CA 90095 USA
- GFZ German Research Centre for Geosciences, Potsdam, 14473 Germany
| | - V A Sergeev
- Saint Petersburg State University, St. Petersburg, 199034 Russia
| | - R P Caron
- Earth, Planetary, and Space Sciences Department, University of California, Los Angeles, CA 90095 USA
- Institute of Geophysics and Planetary Physics, University of California, San Diego, CA USA
| | - M Chung
- Earth, Planetary, and Space Sciences Department, University of California, Los Angeles, CA 90095 USA
- Present Address: Johns Hopkins University Applied Physics Laboratory, Laurel, MD 20723 USA
| | - P Cruce
- Earth, Planetary, and Space Sciences Department, University of California, Los Angeles, CA 90095 USA
- Present Address: Northrop Grumman Aerospace Systems, Redondo Beach, CA 90278 USA
| | - W Greer
- Earth, Planetary, and Space Sciences Department, University of California, Los Angeles, CA 90095 USA
- Institute of Geophysics and Planetary Physics, University of California, San Diego, CA USA
| | - E Grimes
- Earth, Planetary, and Space Sciences Department, University of California, Los Angeles, CA 90095 USA
- Institute of Geophysics and Planetary Physics, University of California, San Diego, CA USA
| | - K Hector
- Earth, Planetary, and Space Sciences Department, University of California, Los Angeles, CA 90095 USA
- Institute of Geophysics and Planetary Physics, University of California, San Diego, CA USA
- Present Address: Raytheon Space and Airborne Systems, El Segundo, CA 90245 USA
| | - M J Lawson
- Earth, Planetary, and Space Sciences Department, University of California, Los Angeles, CA 90095 USA
- Institute of Geophysics and Planetary Physics, University of California, San Diego, CA USA
| | - D Leneman
- Earth, Planetary, and Space Sciences Department, University of California, Los Angeles, CA 90095 USA
- Institute of Geophysics and Planetary Physics, University of California, San Diego, CA USA
| | - E V Masongsong
- Earth, Planetary, and Space Sciences Department, University of California, Los Angeles, CA 90095 USA
- Institute of Geophysics and Planetary Physics, University of California, San Diego, CA USA
| | - C L Russell
- Earth, Planetary, and Space Sciences Department, University of California, Los Angeles, CA 90095 USA
- Institute of Geophysics and Planetary Physics, University of California, San Diego, CA USA
| | - C Wilkins
- Earth, Planetary, and Space Sciences Department, University of California, Los Angeles, CA 90095 USA
- Institute of Geophysics and Planetary Physics, University of California, San Diego, CA USA
| | - D Hinkley
- The Aerospace Corporation, El Segundo, CA 90245 USA
| | - J B Blake
- The Aerospace Corporation, El Segundo, CA 90245 USA
| | - N Adair
- Earth, Planetary, and Space Sciences Department, University of California, Los Angeles, CA 90095 USA
- Present Address: Millenium Space Systems, El Segundo, CA 90245 USA
- Institute of Geophysics and Planetary Physics, University of California, San Diego, CA USA
| | - M Allen
- Earth, Planetary, and Space Sciences Department, University of California, Los Angeles, CA 90095 USA
- Institute of Geophysics and Planetary Physics, University of California, San Diego, CA USA
- Present Address: Northrop Grumman Aerospace Systems, Redondo Beach, CA 90278 USA
| | - M Anderson
- Earth, Planetary, and Space Sciences Department, University of California, Los Angeles, CA 90095 USA
- Present Address: Aptiv, Agoura Hills, CA 91301 USA
- Institute of Geophysics and Planetary Physics, University of California, San Diego, CA USA
| | - M Arreola-Zamora
- Earth, Planetary, and Space Sciences Department, University of California, Los Angeles, CA 90095 USA
- Institute of Geophysics and Planetary Physics, University of California, San Diego, CA USA
| | - J Artinger
- Earth, Planetary, and Space Sciences Department, University of California, Los Angeles, CA 90095 USA
- Institute of Geophysics and Planetary Physics, University of California, San Diego, CA USA
- Physics and Astronomy Department, University of California, Los Angeles, CA 90095 USA
| | - J Asher
- Earth, Planetary, and Space Sciences Department, University of California, Los Angeles, CA 90095 USA
- Institute of Geophysics and Planetary Physics, University of California, San Diego, CA USA
- Present Address: Johns Hopkins University Applied Physics Laboratory, Laurel, MD 20723 USA
| | - D Branchevsky
- Earth, Planetary, and Space Sciences Department, University of California, Los Angeles, CA 90095 USA
- The Aerospace Corporation, El Segundo, CA 90245 USA
- Institute of Geophysics and Planetary Physics, University of California, San Diego, CA USA
| | - M R Capitelli
- Earth, Planetary, and Space Sciences Department, University of California, Los Angeles, CA 90095 USA
- Present Address: Millenium Space Systems, El Segundo, CA 90245 USA
- Institute of Geophysics and Planetary Physics, University of California, San Diego, CA USA
| | - R Castro
- Earth, Planetary, and Space Sciences Department, University of California, Los Angeles, CA 90095 USA
- Institute of Geophysics and Planetary Physics, University of California, San Diego, CA USA
- Present Address: Raytheon Space and Airborne Systems, El Segundo, CA 90245 USA
| | - G Chao
- Earth, Planetary, and Space Sciences Department, University of California, Los Angeles, CA 90095 USA
- Present Address: The Boeing Company, Long Beach, CA 90808 USA
- Institute of Geophysics and Planetary Physics, University of California, San Diego, CA USA
| | - N Chung
- Earth, Planetary, and Space Sciences Department, University of California, Los Angeles, CA 90095 USA
- Present Address: SF Motors, Santa Clara, CA 95054 USA
- Institute of Geophysics and Planetary Physics, University of California, San Diego, CA USA
| | - M Cliffe
- Earth, Planetary, and Space Sciences Department, University of California, Los Angeles, CA 90095 USA
- Present Address: SpaceX, Hawthorne, CA 90250 USA
- Institute of Geophysics and Planetary Physics, University of California, San Diego, CA USA
| | - K Colton
- Earth, Planetary, and Space Sciences Department, University of California, Los Angeles, CA 90095 USA
- Present Address: Planet Labs, Inc., San Francisco, CA 94107 USA
- Institute of Geophysics and Planetary Physics, University of California, San Diego, CA USA
| | - C Costello
- Earth, Planetary, and Space Sciences Department, University of California, Los Angeles, CA 90095 USA
- Computer Science Department, Henry Samueli School of Engineering, University of California, Los Angeles, CA 90095 USA
- Institute of Geophysics and Planetary Physics, University of California, San Diego, CA USA
| | - D Depe
- Earth, Planetary, and Space Sciences Department, University of California, Los Angeles, CA 90095 USA
- Electrical and Computer Engineering Department, Henry Samueli School of Engineering, University of California, Los Angeles, CA 90095 USA
- Institute of Geophysics and Planetary Physics, University of California, San Diego, CA USA
| | - B W Domae
- Earth, Planetary, and Space Sciences Department, University of California, Los Angeles, CA 90095 USA
- Electrical and Computer Engineering Department, Henry Samueli School of Engineering, University of California, Los Angeles, CA 90095 USA
- Institute of Geophysics and Planetary Physics, University of California, San Diego, CA USA
| | - S Eldin
- Earth, Planetary, and Space Sciences Department, University of California, Los Angeles, CA 90095 USA
- Electrical and Computer Engineering Department, Henry Samueli School of Engineering, University of California, Los Angeles, CA 90095 USA
- Institute of Geophysics and Planetary Physics, University of California, San Diego, CA USA
| | - L Fitzgibbon
- Earth, Planetary, and Space Sciences Department, University of California, Los Angeles, CA 90095 USA
- Institute of Geophysics and Planetary Physics, University of California, San Diego, CA USA
- Present Address: Tyvak Nano-Satellite Systems, Inc., Irvine, CA 92618 USA
| | - A Flemming
- Earth, Planetary, and Space Sciences Department, University of California, Los Angeles, CA 90095 USA
- Institute of Geophysics and Planetary Physics, University of California, San Diego, CA USA
- Present Address: Northrop Grumman Aerospace Systems, Redondo Beach, CA 90278 USA
| | - I Fox
- Earth, Planetary, and Space Sciences Department, University of California, Los Angeles, CA 90095 USA
- Institute of Geophysics and Planetary Physics, University of California, San Diego, CA USA
- Mechanical and Aerospace Engineering Department, Henry Samueli School of Engineering, University of California, Los Angeles, CA 90095 USA
| | - D M Frederick
- Earth, Planetary, and Space Sciences Department, University of California, Los Angeles, CA 90095 USA
- Present Address: Millenium Space Systems, El Segundo, CA 90245 USA
- Institute of Geophysics and Planetary Physics, University of California, San Diego, CA USA
| | - A Gilbert
- Earth, Planetary, and Space Sciences Department, University of California, Los Angeles, CA 90095 USA
- Electrical and Computer Engineering Department, Henry Samueli School of Engineering, University of California, Los Angeles, CA 90095 USA
- Institute of Geophysics and Planetary Physics, University of California, San Diego, CA USA
| | - A Gildemeister
- Earth, Planetary, and Space Sciences Department, University of California, Los Angeles, CA 90095 USA
- Institute of Geophysics and Planetary Physics, University of California, San Diego, CA USA
- Present Address: Northrop Grumman Aerospace Systems, Redondo Beach, CA 90278 USA
| | - A Gonzalez
- Earth, Planetary, and Space Sciences Department, University of California, Los Angeles, CA 90095 USA
- Present Address: SpaceX, Hawthorne, CA 90250 USA
- Institute of Geophysics and Planetary Physics, University of California, San Diego, CA USA
| | - B Hesford
- Earth, Planetary, and Space Sciences Department, University of California, Los Angeles, CA 90095 USA
- Present Address: Jet Propulsion Laboratory, Pasadena, CA 91109 USA
- Institute of Geophysics and Planetary Physics, University of California, San Diego, CA USA
| | - S Jha
- Earth, Planetary, and Space Sciences Department, University of California, Los Angeles, CA 90095 USA
- Computer Science Department, Henry Samueli School of Engineering, University of California, Los Angeles, CA 90095 USA
- Institute of Geophysics and Planetary Physics, University of California, San Diego, CA USA
| | - N Kang
- Earth, Planetary, and Space Sciences Department, University of California, Los Angeles, CA 90095 USA
- Present Address: Millenium Space Systems, El Segundo, CA 90245 USA
- Institute of Geophysics and Planetary Physics, University of California, San Diego, CA USA
| | - J King
- Earth, Planetary, and Space Sciences Department, University of California, Los Angeles, CA 90095 USA
- Computer Science Department, Henry Samueli School of Engineering, University of California, Los Angeles, CA 90095 USA
- Institute of Geophysics and Planetary Physics, University of California, San Diego, CA USA
| | - R Krieger
- Earth, Planetary, and Space Sciences Department, University of California, Los Angeles, CA 90095 USA
- Institute of Geophysics and Planetary Physics, University of California, San Diego, CA USA
- Present Address: Mercedes-Benz Research and Development North America, Long Beach, CA 90810 USA
| | - K Lian
- Earth, Planetary, and Space Sciences Department, University of California, Los Angeles, CA 90095 USA
- Institute of Geophysics and Planetary Physics, University of California, San Diego, CA USA
- Present Address: Northrop Grumman Aerospace Systems, Redondo Beach, CA 90278 USA
| | - J Mao
- Earth, Planetary, and Space Sciences Department, University of California, Los Angeles, CA 90095 USA
- Institute of Geophysics and Planetary Physics, University of California, San Diego, CA USA
- Present Address: Verona, WI 53593 USA
| | - E McKinney
- Earth, Planetary, and Space Sciences Department, University of California, Los Angeles, CA 90095 USA
- Institute of Geophysics and Planetary Physics, University of California, San Diego, CA USA
- Present Address: California State Polytechnic University, Pomona, CA 91768 USA
| | - J P Miller
- Earth, Planetary, and Space Sciences Department, University of California, Los Angeles, CA 90095 USA
- Computer Science Department, Henry Samueli School of Engineering, University of California, Los Angeles, CA 90095 USA
- Institute of Geophysics and Planetary Physics, University of California, San Diego, CA USA
| | - A Norris
- Earth, Planetary, and Space Sciences Department, University of California, Los Angeles, CA 90095 USA
| | - M Nuesca
- Earth, Planetary, and Space Sciences Department, University of California, Los Angeles, CA 90095 USA
- Computer Science Department, Henry Samueli School of Engineering, University of California, Los Angeles, CA 90095 USA
- Institute of Geophysics and Planetary Physics, University of California, San Diego, CA USA
| | - A Palla
- Earth, Planetary, and Space Sciences Department, University of California, Los Angeles, CA 90095 USA
- Computer Science Department, Henry Samueli School of Engineering, University of California, Los Angeles, CA 90095 USA
- Institute of Geophysics and Planetary Physics, University of California, San Diego, CA USA
| | - E S Y Park
- Earth, Planetary, and Space Sciences Department, University of California, Los Angeles, CA 90095 USA
- Institute of Geophysics and Planetary Physics, University of California, San Diego, CA USA
- Present Address: Economics Department, University of California, Los Angeles, CA 90095 USA
| | - C E Pedersen
- Earth, Planetary, and Space Sciences Department, University of California, Los Angeles, CA 90095 USA
- Institute of Geophysics and Planetary Physics, University of California, San Diego, CA USA
- Mechanical and Aerospace Engineering Department, Henry Samueli School of Engineering, University of California, Los Angeles, CA 90095 USA
| | - Z Qu
- Earth, Planetary, and Space Sciences Department, University of California, Los Angeles, CA 90095 USA
- Institute of Geophysics and Planetary Physics, University of California, San Diego, CA USA
- Mechanical and Aerospace Engineering Department, Henry Samueli School of Engineering, University of California, Los Angeles, CA 90095 USA
| | - R Rozario
- Earth, Planetary, and Space Sciences Department, University of California, Los Angeles, CA 90095 USA
- Present Address: SpaceX, Hawthorne, CA 90250 USA
- Institute of Geophysics and Planetary Physics, University of California, San Diego, CA USA
| | - E Rye
- Earth, Planetary, and Space Sciences Department, University of California, Los Angeles, CA 90095 USA
- Electrical and Computer Engineering Department, Henry Samueli School of Engineering, University of California, Los Angeles, CA 90095 USA
- Institute of Geophysics and Planetary Physics, University of California, San Diego, CA USA
| | - R Seaton
- Earth, Planetary, and Space Sciences Department, University of California, Los Angeles, CA 90095 USA
- Institute of Geophysics and Planetary Physics, University of California, San Diego, CA USA
- Mechanical and Aerospace Engineering Department, Henry Samueli School of Engineering, University of California, Los Angeles, CA 90095 USA
| | - A Subramanian
- Earth, Planetary, and Space Sciences Department, University of California, Los Angeles, CA 90095 USA
- Institute of Geophysics and Planetary Physics, University of California, San Diego, CA USA
- Present Address: Northrop Grumman Aerospace Systems, Redondo Beach, CA 90278 USA
| | - S R Sundin
- Earth, Planetary, and Space Sciences Department, University of California, Los Angeles, CA 90095 USA
- Institute of Geophysics and Planetary Physics, University of California, San Diego, CA USA
- Present Address: Tyvak Nano-Satellite Systems, Inc., Irvine, CA 92618 USA
| | - A Tan
- Earth, Planetary, and Space Sciences Department, University of California, Los Angeles, CA 90095 USA
- Institute of Geophysics and Planetary Physics, University of California, San Diego, CA USA
- Present Address: Experior Laboratories, Oxnard, CA 93033 USA
| | - W Turner
- Earth, Planetary, and Space Sciences Department, University of California, Los Angeles, CA 90095 USA
- Institute of Geophysics and Planetary Physics, University of California, San Diego, CA USA
- Physics and Astronomy Department, University of California, Los Angeles, CA 90095 USA
| | - A J Villegas
- Earth, Planetary, and Space Sciences Department, University of California, Los Angeles, CA 90095 USA
- Institute of Geophysics and Planetary Physics, University of California, San Diego, CA USA
- Physics and Astronomy Department, University of California, Los Angeles, CA 90095 USA
| | - M Wasden
- Earth, Planetary, and Space Sciences Department, University of California, Los Angeles, CA 90095 USA
- Institute of Geophysics and Planetary Physics, University of California, San Diego, CA USA
- Mechanical and Aerospace Engineering Department, Henry Samueli School of Engineering, University of California, Los Angeles, CA 90095 USA
| | - G Wing
- Earth, Planetary, and Space Sciences Department, University of California, Los Angeles, CA 90095 USA
- Computer Science Department, Henry Samueli School of Engineering, University of California, Los Angeles, CA 90095 USA
- Institute of Geophysics and Planetary Physics, University of California, San Diego, CA USA
| | - C Wong
- Earth, Planetary, and Space Sciences Department, University of California, Los Angeles, CA 90095 USA
- Institute of Geophysics and Planetary Physics, University of California, San Diego, CA USA
- Physics and Astronomy Department, University of California, Los Angeles, CA 90095 USA
| | - E Xie
- Earth, Planetary, and Space Sciences Department, University of California, Los Angeles, CA 90095 USA
- Electrical and Computer Engineering Department, Henry Samueli School of Engineering, University of California, Los Angeles, CA 90095 USA
- Institute of Geophysics and Planetary Physics, University of California, San Diego, CA USA
| | - S Yamamoto
- Earth, Planetary, and Space Sciences Department, University of California, Los Angeles, CA 90095 USA
- Institute of Geophysics and Planetary Physics, University of California, San Diego, CA USA
- Mechanical and Aerospace Engineering Department, Henry Samueli School of Engineering, University of California, Los Angeles, CA 90095 USA
| | - R Yap
- Earth, Planetary, and Space Sciences Department, University of California, Los Angeles, CA 90095 USA
- Institute of Geophysics and Planetary Physics, University of California, San Diego, CA USA
- Mathematics Department, University of California, Los Angeles, CA 90095 USA
| | - A Zarifian
- Earth, Planetary, and Space Sciences Department, University of California, Los Angeles, CA 90095 USA
- Present Address: Jet Propulsion Laboratory, Pasadena, CA 91109 USA
- Institute of Geophysics and Planetary Physics, University of California, San Diego, CA USA
| | - G Y Zhang
- Earth, Planetary, and Space Sciences Department, University of California, Los Angeles, CA 90095 USA
- Institute of Geophysics and Planetary Physics, University of California, San Diego, CA USA
- Present Address: Qualcomm, San Diego, CA 92121 USA
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14
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Che H, Schiff C, Le G, Dorelli J, Giles B, Moore T. Quantifying the Effect of Non-Larmor Motion of Electrons on the Pressure Tensor. PHYSICS OF PLASMAS 2018; 25:032101. [PMID: 32905417 PMCID: PMC7473318 DOI: 10.1063/1.5016853] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
In space plasma, various effects of magnetic reconnection and turbulence cause the electron motion to significantly deviate from their Larmor orbits. Collectively these orbits affect the electron velocity distribution function and lead to the appearance of the "non-gyrotropic" elements in the pressure tensor. Quantification of this effect has important applications in space and laboratory plasma, one of which is tracing the electron diffusion region (EDR) of magnetic reconnection in space observations. Three different measures of agyrotropy of pressure tensor have previously been proposed, namely, A∅ e , Dng and Q. The multitude of contradictory measures has caused confusion within the community. We revisit the problem by considering the basic properties an agyrotropy measure should have. We show that A∅ e , Dng and Q are all defined based on the sum of the principle minors (i.e. the rotation invariant I 2) of the pressure tensor. We discuss in detail the problems of I 2-based measures and explain why they may produce ambiguous and biased results. We introduce a new measure AG constructed based on the determinant of the pressure tensor (i.e. the rotation invariant I 3) which does not suffer from the problems of I 2-based measures. We compare AG with other measures in 2 and 3-dimension particle-in-cell magnetic reconnection simulations, and show that AG can effectively trace the EDR of reconnection in both Harris and force-free current sheets. On the other hand, A∅ e does not show prominent peaks in the EDR and part of the separatrix in the force-free reconnection simulations, demonstrating that A∅ e does not measure all the non-gyrotropic effects in this case, and is not suitable for studying magnetic reconnection in more general situations other than Harris sheet reconnection.
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Affiliation(s)
- H Che
- University of Maryland, College Park, MD, 20742, USA
- NASA Goddard Space Flight Center, Greenbelt, MD, 20771, USA
| | - C Schiff
- NASA Goddard Space Flight Center, Greenbelt, MD, 20771, USA
| | - G Le
- NASA Goddard Space Flight Center, Greenbelt, MD, 20771, USA
| | - J Dorelli
- NASA Goddard Space Flight Center, Greenbelt, MD, 20771, USA
| | - B Giles
- NASA Goddard Space Flight Center, Greenbelt, MD, 20771, USA
| | - T Moore
- NASA Goddard Space Flight Center, Greenbelt, MD, 20771, USA
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15
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Egedal J, Le A, Daughton W, Wetherton B, Cassak PA, Burch JL, Lavraud B, Dorelli J, Gershman DJ, Avanov LA. Spacecraft Observations of Oblique Electron Beams Breaking the Frozen-In Law During Asymmetric Reconnection. PHYSICAL REVIEW LETTERS 2018; 120:055101. [PMID: 29481157 DOI: 10.1103/physrevlett.120.055101] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Indexed: 06/08/2023]
Abstract
Fully kinetic simulations of asymmetric magnetic reconnection reveal the presence of magnetic-field-aligned beams of electrons flowing toward the topological magnetic x line. Within the ∼6d_{e} electron-diffusion region, the beams become oblique to the local magnetic field, providing a unique signature of the electron-diffusion region where the electron frozen-in law is broken. The numerical predictions are confirmed by in situ Magnetospheric Multiscale spacecraft observations during asymmetric reconnection at Earth's dayside magnetopause.
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Affiliation(s)
- J Egedal
- Department of Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - A Le
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - W Daughton
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - B Wetherton
- Department of Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - P A Cassak
- Department of Physics and Astronomy, West Virginia University, Morgantown, West Virginia 26506, USA
| | - J L Burch
- Southwest Research Institute, San Antonio, Texas 78238, USA
| | - B Lavraud
- Institut de Recherche en Astrophysique et Planétologie, Université de Toulouse, UMR 5277, Toulouse, France
| | - J Dorelli
- Heliophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
| | - D J Gershman
- Heliophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
| | - L A Avanov
- Heliophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
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16
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Egedal J, Le A, Daughton W, Wetherton B, Cassak PA, Chen LJ, Lavraud B, Torbert RB, Dorelli J, Gershman DJ, Avanov LA. Spacecraft Observations and Analytic Theory of Crescent-Shaped Electron Distributions in Asymmetric Magnetic Reconnection. PHYSICAL REVIEW LETTERS 2016; 117:185101. [PMID: 27835028 PMCID: PMC7437547 DOI: 10.1103/physrevlett.117.185101] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Indexed: 06/06/2023]
Abstract
Supported by a kinetic simulation, we derive an exclusion energy parameter E_{X} providing a lower kinetic energy bound for an electron to cross from one inflow region to the other during magnetic reconnection. As by a Maxwell demon, only high-energy electrons are permitted to cross the inner reconnection region, setting the electron distribution function observed along the low-density side separatrix during asymmetric reconnection. The analytic model accounts for the two distinct flavors of crescent-shaped electron distributions observed by spacecraft in a thin boundary layer along the low-density separatrix.
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Affiliation(s)
- J Egedal
- Department of Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - A Le
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - W Daughton
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - B Wetherton
- Department of Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
| | - P A Cassak
- Department of Physics and Astronomy, West Virginia University, Morgantown, West Virginia 26506, USA
| | - L-J Chen
- Heliophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
| | - B Lavraud
- Institut de Recherche en Astrophysique et Planétologie, Université de Toulouse, Toulouse, France, and Centre National de la Recherche Scientifique, UMR 5277, Toulouse, France
| | - R B Torbert
- University of New Hampshire, Durham, New Hampshire 03824, USA
| | - J Dorelli
- Heliophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
| | - D J Gershman
- Heliophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
| | - L A Avanov
- Heliophysics Science Division, NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
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17
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Artemyev AV, Vainchtein DL, Neishtadt AI, Zelenyi LM. Charged particle dynamics in turbulent current sheets. Phys Rev E 2016; 93:053207. [PMID: 27300995 DOI: 10.1103/physreve.93.053207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2016] [Indexed: 11/07/2022]
Abstract
We study dynamics of charged particle in current sheets with magnetic fluctuations. We use the adiabatic theory to describe the nonperturbed charged particle motion and show that magnetic field fluctuations destroy the adiabatic invariant. We demonstrate that the evolution of particle adiabatic invariant's distribution is described by a diffusion equation and derive analytical estimates of the rate of adiabatic invariant's diffusion. This rate is proportional to power density of magnetic field fluctuations. We compare analytical estimates with numerical simulations. We show that adiabatic invariant diffusion results in transient particles trapping in the current sheet. For magnetic field fluctuation amplitude a few times larger than a normal magnetic field component, more than 50% of transient particles become trapped. We discuss the possible consequences of destruction of adiabaticity of the charged particle motion on the state of the current sheets.
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Affiliation(s)
- A V Artemyev
- Space Research Institute RAS, Moscow 117997, Russia
| | | | | | - L M Zelenyi
- Space Research Institute RAS, Moscow 117997, Russia
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18
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Shustov PI, Artemyev AV, Yushkov EV. Intermediate regime of charged particle scattering in the field-reversal configuration. CHAOS (WOODBURY, N.Y.) 2015; 25:123118. [PMID: 26723157 DOI: 10.1063/1.4938535] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
In this paper, we investigate the charged particle scattering in the magnetic field configuration with stretched magnetic field lines. This scattering results from the violation of the adiabaticity of charged particle motion in the region with the strong gradient of the magnetic field. We consider the intermediate regime of charged particle dynamics, when the violation of the adiabaticity is significant enough, but particle motion is not chaotic. We demonstrate and describe the significant scattering of particles with large adiabatic invariants (magnetic moment). We discuss a possible application of obtained results for description of the peculiarities of pitch-angle diffusion of relativistic electrons in the Earth radiation belts.
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Affiliation(s)
- P I Shustov
- Space Research Institute, RAS, Profsouznaya st., 84/32, GSP-7, 117997 Moscow, Russia
| | - A V Artemyev
- Space Research Institute, RAS, Profsouznaya st., 84/32, GSP-7, 117997 Moscow, Russia
| | - E V Yushkov
- Space Research Institute, RAS, Profsouznaya st., 84/32, GSP-7, 117997 Moscow, Russia
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19
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Sasunov YL, Khodachenko ML, Alexeev II, Belenkaya ES, Gordeev EI, Kubyshkin IV. The energy-based scaling of a thin current sheet: Case study. GEOPHYSICAL RESEARCH LETTERS 2015; 42:9609-9616. [PMID: 27609999 PMCID: PMC4994317 DOI: 10.1002/2015gl066189] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Revised: 10/15/2015] [Accepted: 10/15/2015] [Indexed: 06/06/2023]
Abstract
The influence of average plasma energy E~ on the half thickness ℓ of a thin current sheet (TCS) is investigated for three cases of TCSs crossings. The value of ℓ was estimated from the magnetic field data by means of Cluster observations. The obtained scaling values for TCSs, Z~=ℓ/ρT, where ρT is the thermal Larmor radius, were compared with the scaling Zμ=22E~/T, where E~ and T are the average plasma energy and the temperature of plasma, which assumes a specific dynamics (conservation of magnetic flux through the trajectory segment) of the current carriers. The comparison of Z~ and Zμ shows a good agreement.
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Affiliation(s)
- Yu L Sasunov
- Space Research Institute Austrian Academy of Sciences Graz Austria
| | - M L Khodachenko
- Space Research Institute Austrian Academy of Sciences Graz Austria; Skobeltsyn Institute of Nuclear Physics Federal State Budget Educational Institution of Higher Education M.V.Lomonosov Moscow State University Moscow Russia
| | - I I Alexeev
- Skobeltsyn Institute of Nuclear Physics Federal State Budget Educational Institution of Higher Education M.V.Lomonosov Moscow State University Moscow Russia
| | - E S Belenkaya
- Skobeltsyn Institute of Nuclear Physics Federal State Budget Educational Institution of Higher Education M.V.Lomonosov Moscow State University Moscow Russia
| | - E I Gordeev
- Earth Physics Department Saint Petersburg State University Saint Petersburg Russia
| | - I V Kubyshkin
- Earth Physics Department Saint Petersburg State University Saint Petersburg Russia
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20
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Hietala H, Drake JF, Phan TD, Eastwood JP, McFadden JP. Ion temperature anisotropy across a magnetotail reconnection jet. GEOPHYSICAL RESEARCH LETTERS 2015; 42:7239-7247. [PMID: 27478283 PMCID: PMC4950132 DOI: 10.1002/2015gl065168] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Revised: 08/17/2015] [Accepted: 08/19/2015] [Indexed: 06/02/2023]
Abstract
A significant fraction of the energy released by magnetotail reconnection appears to go into ion heating, but this heating is generally anisotropic. We examine ARTEMIS dual-spacecraft observations of a long-duration magnetotail exhaust generated by antiparallel reconnection in conjunction with particle-in-cell simulations, showing spatial variations in the anisotropy across the outflow far (>100di ) downstream of the X line. A consistent pattern is found in both the spacecraft data and the simulations: While the total temperature across the exhaust is rather constant, near the boundaries Ti,|| dominates. The plasma is well above the firehose threshold within patchy spatial regions at |BX |∈[0.1,0.5]B0, suggesting that the drive for the instability is strong and the instability is too weak to relax the anisotropy. At the midplane ( |BX|≲0.1B0), Ti,⊥>Ti,|| and ions undergo Speiser-like motion despite the large distance from the X line.
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Affiliation(s)
- H. Hietala
- The Blackett LaboratoryImperial CollegeLondonUK
| | - J. F. Drake
- Department of Physics, the Institute for Physical Science and Technology and the Joint Space InstituteUniversity of MarylandCollege ParkMarylandUSA
| | - T. D. Phan
- Space Science LaboratoryUniversity of CaliforniaBerkeleyCaliforniaUSA
| | | | - J. P. McFadden
- Space Science LaboratoryUniversity of CaliforniaBerkeleyCaliforniaUSA
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Saito M. THEMIS two-point measurements of the cross-tail current density: A thick bifurcated current sheet in the near-Earth plasma sheet. JOURNAL OF GEOPHYSICAL RESEARCH. SPACE PHYSICS 2015; 120:6258-6275. [PMID: 27722039 PMCID: PMC5046188 DOI: 10.1002/2015ja021142] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/19/2015] [Revised: 06/22/2015] [Accepted: 07/10/2015] [Indexed: 06/06/2023]
Abstract
The basic properties of the near-Earth current sheet from 8 RE to 12 RE were determined based on Time History of Events and Macroscale Interactions during Substorms (THEMIS) observations from 2007 to 2013. Ampere's law was used to estimate the current density when the locations of two spacecraft were suitable for the calculation. A total of 3838 current density observations were obtained to study the vertical profile. For typical solar wind conditions, the current density near (off) the central plane of the current sheet ranged from 1 to 2 nA/m2 (1 to 8 nA/m2). All the high current densities appeared off the central plane of the current sheet, indicating the formation of a bifurcated current sheet structure when the current density increased above 2 nA/m2. The median profile also showed a bifurcated structure, in which the half thickness was about 3 RE . The distance between the peak of the current density and the central plane of the current sheet was 0.5 to 1 RE . High current densities above 4 nA/m2 were observed in some cases that occurred preferentially during substorms, but they also occurred in quiet times. In contrast to the commonly accepted picture, these high current densities can form without a high solar wind dynamic pressure. In addition, these high current densities can appear in two magnetic configurations: tail-like and dipolar structures. At least two mechanisms, magnetic flux depletion and new current system formation during the expansion phase, other than plasma sheet compression are responsible for the formation of the bifurcated current sheets.
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Affiliation(s)
- Miho Saito
- Earth and Planetary Sciences Tokyo Institute of Technology Meguro Japan
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22
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Artemyev AV, Vasiliev AA. Resonant ion acceleration by plasma jets: Effects of jet breaking and the magnetic-field curvature. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2015; 91:053104. [PMID: 26066269 DOI: 10.1103/physreve.91.053104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Indexed: 06/04/2023]
Abstract
In this paper we consider resonant ion acceleration by a plasma jet originating from the magnetic reconnection region. Such jets propagate in the background magnetic field with significantly curved magnetic-field lines. Decoupling of ion and electron motions at the leading edge of the jet results in generation of strong electrostatic fields. Ions can be trapped by this field and get accelerated along the jet front. This mechanism of resonant acceleration resembles surfing acceleration of charged particles at a shock wave. To describe resonant acceleration of ions, we use adiabatic theory of resonant phenomena. We show that particle motion along the curved field lines significantly influences the acceleration rate. The maximum gain of energy is determined by the particle's escape from the system due to this motion. Applications of the proposed mechanism to charged-particle acceleration in the planetary magnetospheres and the solar corona are discussed.
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Affiliation(s)
- A V Artemyev
- Space Research Institute (IKI) 117997, 84/32 Profsoyuznaya Str, Moscow, Russia
| | - A A Vasiliev
- Space Research Institute (IKI) 117997, 84/32 Profsoyuznaya Str, Moscow, Russia
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23
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Artemyev AV, Neishtadt AI, Zelenyi LM. Rapid geometrical chaotization in slow-fast Hamiltonian systems. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2014; 89:060902. [PMID: 25019711 DOI: 10.1103/physreve.89.060902] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Indexed: 06/03/2023]
Abstract
In this Rapid Communication we demonstrate effects of a new mechanism of adiabaticity destruction in Hamiltonian systems with a separatrix in the phase space. In contrast to the slow diffusive-like destruction typical for many systems, this new mechanism is responsible for very fast chaotization in a large phase volume. To investigate this mechanism we consider a Hamiltonian system with two degrees of freedom and with a separatrix in the phase plane of fast variables. The fast chaotization is due to an asymmetry of the separatrix and corresponding geometrical jumps of an adiabatic invariant. This system describes the motion of charged particles in a inhomogeneous electromagnetic field with a specific configuration. We show that geometrical jumps of the adiabatic invariant result in a very fast chaotization of particle motion.
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Affiliation(s)
- A V Artemyev
- Space Research Institute RAS, Moscow 117997, Russia
| | - A I Neishtadt
- Space Research Institute RAS, Moscow 117997, Russia and Department of Mathematical Sciences, Loughborough University, Loughborough LE11 3TU, United Kingdom
| | - L M Zelenyi
- Space Research Institute RAS, Moscow 117997, Russia
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24
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Ukhorskiy AY, Sitnov MI, Merkin VG, Artemyev AV. Rapid acceleration of protons upstream of earthward propagating dipolarization fronts. JOURNAL OF GEOPHYSICAL RESEARCH. SPACE PHYSICS 2013; 118:4952-4962. [PMID: 26167430 PMCID: PMC4497486 DOI: 10.1002/jgra.50452] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2012] [Revised: 06/27/2013] [Accepted: 07/13/2013] [Indexed: 06/03/2023]
Abstract
[1] Transport and acceleration of ions in the magnetotail largely occurs in the form of discrete impulsive events associated with a steep increase of the tail magnetic field normal to the neutral plane (Bz ), which are referred to as dipolarization fronts. The goal of this paper is to investigate how protons initially located upstream of earthward moving fronts are accelerated at their encounter. According to our analytical analysis and simplified two-dimensional test-particle simulations of equatorially mirroring particles, there are two regimes of proton acceleration: trapping and quasi-trapping, which are realized depending on whether the front is preceded by a negative depletion in Bz . We then use three-dimensional test-particle simulations to investigate how these acceleration processes operate in a realistic magnetotail geometry. For this purpose we construct an analytical model of the front which is superimposed onto the ambient field of the magnetotail. According to our numerical simulations, both trapping and quasi-trapping can produce rapid acceleration of protons by more than an order of magnitude. In the case of trapping, the acceleration levels depend on the amount of time particles stay in phase with the front which is controlled by the magnetic field curvature ahead of the front and the front width. Quasi-trapping does not cause particle scattering out of the equatorial plane. Energization levels in this case are limited by the number of encounters particles have with the front before they get magnetized behind it.
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Affiliation(s)
- AY Ukhorskiy
- The Johns Hopkins University Applied Physics Laboratory, LaurelMaryland, USA
| | - MI Sitnov
- The Johns Hopkins University Applied Physics Laboratory, LaurelMaryland, USA
| | - VG Merkin
- The Johns Hopkins University Applied Physics Laboratory, LaurelMaryland, USA
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25
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Le A, Egedal J, Ohia O, Daughton W, Karimabadi H, Lukin VS. Regimes of the electron diffusion region in magnetic reconnection. PHYSICAL REVIEW LETTERS 2013; 110:135004. [PMID: 23581331 DOI: 10.1103/physrevlett.110.135004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2012] [Indexed: 06/02/2023]
Abstract
The electron diffusion region during magnetic reconnection lies in different regimes depending on the pressure anisotropy, which is regulated by the properties of thermal electron orbits. In kinetic simulations at the weakest guide fields, pitch angle mixing in velocity space causes the outflow electron pressure to become nearly isotropic. Above a threshold guide field that depends on a range of parameters, including the normalized electron pressure and the ion-to-electron mass ratio, electron pressure anisotropy develops in the exhaust and supports extended current layers. This new regime with electron current sheets extending to the system size is also reproduced by fluid simulations with an anisotropic closure for the electron pressure. It offers an explanation for recent spacecraft observations.
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Affiliation(s)
- A Le
- Department of Physics, Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
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26
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Extended Consideration of a Synthesis Model for Magnetospheric Substorms. ACTA ACUST UNITED AC 2013. [DOI: 10.1029/gm064p0043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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27
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Baker DN, Pulkkinen TI, McPherron RL, Craven JD, Frank LA, Elphinstone RD, Murphree JS, Fennell JF, Lopez RE, Nagai T. CDAW 9 analysis of magnetospheric events on May 3, 1986: Event C. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/92ja02475] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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28
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Ashour-Abdalla M, Büchner J, Zelenyi LM. The quasi-adiabatic ion distribution in the central plasma sheet and its boundary layer. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/90ja01921] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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29
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Liu WW, Rostoker G. Energetic ring current particles generated by recurring substorm cycles. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/95ja01934] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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30
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Lui ATY, Yoon PH, Chang CL. Quasi-linear analysis of ion Weibel instability in the Earth's neutral sheet. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/92ja02034] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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31
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32
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Hoshino M. Stochastic particle acceleration in multiple magnetic islands during reconnection. PHYSICAL REVIEW LETTERS 2012; 108:135003. [PMID: 22540708 DOI: 10.1103/physrevlett.108.135003] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2011] [Indexed: 05/31/2023]
Abstract
A nonthermal particle acceleration mechanism involving the interaction of a charged particle with multiple magnetic islands is proposed. The original Fermi acceleration model, which assumes randomly distributed magnetic clouds moving at random velocity V(c) in the interstellar medium, is known to be of second-order acceleration of O(V(c)/c)(2) owing to the combination of head-on and head-tail collisions. In this Letter, we reconsider the original Fermi model by introducing multiple magnetic islands during reconnection instead of magnetic clouds. We discuss that the energetic particles have a tendency to be distributed outside the magnetic islands, and they mainly interact with reconnection outflow jets. As a result, the acceleration efficiency becomes first order of O(V(A)/c), where V(A) and c are the Alfvén velocity and the speed of light, respectively.
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Affiliation(s)
- Masahiro Hoshino
- Department of Earth and Planetary Science, University of Tokyo, Tokyo 113-0033, Japan.
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33
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Artemyev AV, Neishtadt AI, Zelenyi LM. Jumps of adiabatic invariant at the separatrix of a degenerate saddle point. CHAOS (WOODBURY, N.Y.) 2011; 21:043120. [PMID: 22225357 DOI: 10.1063/1.3657916] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We consider a slow-fast Hamiltonian system with two degrees of freedom. One degree of freedom corresponds to slow variables, and the other one corresponds to fast variables. A characteristic ratio of the rates of change of slow and fast variables is a small parameter κ. For every fixed value of the slow variables, in the phase portrait of the fast variables there are a saddle point and separatrices passing through it. When the slow variables change, phase points may cross the separatrices. The action variable of the fast motion is an adiabatic invariant of the full system as long as a trajectory is far from the separatrices: value of the adiabatic invariant is conserved with an accuracy of order of κ on time intervals of order of 1/κ. A passage through a narrow neighborhood of the separatrices results in a jump of the adiabatic invariant. We consider a case when the saddle point is degenerate. We derive an asymptotic formula for the jump of the adiabatic invariant which turns out to be a value of order of κ(3/4) (in the case of a non-degenarate saddle point a similar jump is known to be a value of order of κ). Accumulation of these jumps after many consecutive separatrix crossings leads to the "diffusion" of the adiabatic invariant and chaotic dynamics. We verify the analytical expression for the jump of the adiabatic invariant by numerical simulations. We discuss application of the obtained results to the description of charged particle dynamics in the Earth magnetosphere.
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Affiliation(s)
- A V Artemyev
- Space Research Institute, RAS, Profsouznaya St., 84/32, GSP-7, 117997 Moscow, Russia.
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34
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Ukhorskiy AY, Sitnov MI, Millan RM, Kress BT. The role of drift orbit bifurcations in energization and loss of electrons in the outer radiation belt. ACTA ACUST UNITED AC 2011. [DOI: 10.1029/2011ja016623] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- A. Y. Ukhorskiy
- Johns Hopkins University Applied Physics Laboratory; Laurel Maryland USA
| | - M. I. Sitnov
- Johns Hopkins University Applied Physics Laboratory; Laurel Maryland USA
| | - R. M. Millan
- Department of Physics and Astronomy; Dartmouth College; Hanover New Hampshire USA
| | - B. T. Kress
- Department of Physics and Astronomy; Dartmouth College; Hanover New Hampshire USA
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35
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Rong Z, Shen C, Lucek E, Balogh A, Yao L. Statistical survey on the magnetic field in magnetotail current sheets: Cluster observations. CHINESE SCIENCE BULLETIN-CHINESE 2010. [DOI: 10.1007/s11434-010-3096-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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36
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Neishtadt A, Vasiliev A. On the absence of stable periodic orbits in domains of separatrix crossings in nonsymmetric slow-fast Hamiltonian systems. CHAOS (WOODBURY, N.Y.) 2007; 17:043104. [PMID: 18163768 DOI: 10.1063/1.2790368] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
We consider a two degree of freedom Hamiltonian system with one degree of freedom corresponding to fast motion and the other corresponding to slow motion. We assume that at frozen values of the slow variables there is a separatrix on the phase plane of the fast variables and there is a region in the phase space (the domain of separatrix crossings) where projections of phase points onto the plane of the fast variables repeatedly cross the separatrix in the process of evolution of the slow variables. Under rather general conditions, we prove that there are no stable periodic trajectories of any prescribed period inside the domain of separatrix crossings, except maybe for periodic trajectories passing anomalously close to the saddle point.
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Affiliation(s)
- Anatoly Neishtadt
- Department of Math. Sciences, Loughborough University, Loughborough, LE11 3TU, United Kingdom
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37
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Affiliation(s)
- M. Kaan Öztürk
- Department of Physics and Astronomy; Rice University; Houston Texas USA
| | - R. A. Wolf
- Department of Physics and Astronomy; Rice University; Houston Texas USA
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38
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Kirk JG. Particle acceleration in relativistic current sheets. PHYSICAL REVIEW LETTERS 2004; 92:181101. [PMID: 15169478 DOI: 10.1103/physrevlett.92.181101] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2003] [Indexed: 05/24/2023]
Abstract
Relativistic current sheets have been proposed as the sites of dissipation in pulsar winds, jets in active galaxies, and other Poynting flux dominated flows. It is shown that the steady versions of these structures differ from their nonrelativistic counterparts because they do not permit transformation to a de Hofmann-Teller frame with zero electric field. Instead, their generic form is that of a true neutral sheet with no linking magnetic field component normal to the sheet. The maximum energy to which such structures can accelerate particles is derived, and used to compute the maximum frequency of the subsequent synchrotron radiation. This can be substantially in excess of standard estimates. In the magnetically driven gamma-ray burst scenario, acceleration of electrons is possible to energies sufficient to enable photon-photon pair production after an inverse Compton scattering event.
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Affiliation(s)
- J G Kirk
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, D-69117 Heidelberg, Germany.
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39
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Shen C, Li X, Dunlop M, Liu ZX, Balogh A, Baker DN, Hapgood M, Wang X. Analyses on the geometrical structure of magnetic field in the current sheet based on cluster measurements. ACTA ACUST UNITED AC 2003. [DOI: 10.1029/2002ja009612] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- C. Shen
- Laboratory for Space Weather, Chinese Cluster Data and Research Center, Center for Space Science and Applied Research; Chinese Academy of Sciences; Beijing China
| | - X. Li
- Laboratory for Atmosphere and Space Physics; University of Colorado; Boulder USA
| | - M. Dunlop
- Imperial College of Science; Technology, and Medicine; London UK
- Rutherford Appleton Laboratory; Chilton, Didcot, Oxfordshire UK
| | - Z. X. Liu
- Laboratory for Space Weather, Chinese Cluster Data and Research Center, Center for Space Science and Applied Research; Chinese Academy of Sciences; Beijing China
| | - A. Balogh
- Imperial College of Science; Technology, and Medicine; London UK
| | - D. N. Baker
- Laboratory for Atmosphere and Space Physics; University of Colorado; Boulder USA
| | - M. Hapgood
- Rutherford Appleton Laboratory; Chilton, Didcot, Oxfordshire UK
| | - X. Wang
- Laboratory for Space Weather, Chinese Cluster Data and Research Center, Center for Space Science and Applied Research; Chinese Academy of Sciences; Beijing China
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40
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Hoshino M, Mukai T, Terasawa T, Shinohara I. Suprathermal electron acceleration in magnetic reconnection. ACTA ACUST UNITED AC 2001. [DOI: 10.1029/2001ja900052] [Citation(s) in RCA: 278] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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41
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Sitnov MI, Zelenyi LM, Malova HV, Sharma AS. Thin current sheet embedded within a thicker plasma sheet: Self-consistent kinetic theory. ACTA ACUST UNITED AC 2000. [DOI: 10.1029/1999ja000431] [Citation(s) in RCA: 110] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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42
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Antonova EE, Stepanova MV, Vikhreva EA, Ovchinnikov IL, Teltzov MV. Generation of unmagnetized motion of plasma sheet electrons and its possible causes. ACTA ACUST UNITED AC 1999. [DOI: 10.1029/1999ja900036] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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43
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Anderson BJ, Decker RB, Paschalidis NP, Sarris T. Onset of nonadiabatic particle motion in the near-Earth magnetotail. ACTA ACUST UNITED AC 1997. [DOI: 10.1029/97ja00798] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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44
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Neishtadt AI, Sidorenko VV, Treschev DV. Stable periodic motions in the problem on passage through a separatrix. CHAOS (WOODBURY, N.Y.) 1997; 7:2-11. [PMID: 12779632 DOI: 10.1063/1.166236] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
A Hamiltonian system with one degree of freedom depending on a slowly periodically varying in time parameter is considered. For every fixed value of the parameter there are separatrices on the phase portrait of the system. When parameter is changing in time, these separatrices are pulsing slowly periodically, and phase points of the system cross them repeatedly. In numeric experiments region swept by pulsing separatrices looks like a region of chaotic motion. However, it is shown in the present paper that if the system possesses some additional symmetry (like a pendulum in a slowly varying gravitational field), then typically in the region in question there are many periodic solutions surrounded by stability islands; total measure of these islands does not vanish and does not tend to 0 as rate of changing of the parameter tends to 0.(c) 1997 American Institute of Physics.
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Affiliation(s)
- A. I. Neishtadt
- Space Research Institute, Profsoyuznaya 84/32, Moscow 117810, Russia
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45
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Lui ATY. Current disruption in the Earth's magnetosphere: Observations and models. ACTA ACUST UNITED AC 1996. [DOI: 10.1029/96ja00079] [Citation(s) in RCA: 447] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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46
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On the selection of a coordinate system for high latitude radiation. RADIAT MEAS 1996. [DOI: 10.1016/1350-4487(96)00010-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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47
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Frank LA, Paterson WR, Kivelson MG. Observations of nonadiabatic acceleration of ions in Earth's magnetotail. ACTA ACUST UNITED AC 1994. [DOI: 10.1029/94ja00780] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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48
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Ullaland S, Kremser G, Tanskanen P, Korth A, Roux A, Torkar K, Block LP, Iversen IB. On the development of a magnetospheric substorm influenced by a storm sudden commencement: Ground, balloon, and satellite observations. ACTA ACUST UNITED AC 1993. [DOI: 10.1029/93ja01145] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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49
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An alternative interpretation of auroral precipitation and luminosity observations from the DE, DMSP, AUREOL, and Viking satellites in terms of their mapping to the nightside magnetosphere. ACTA ACUST UNITED AC 1993. [DOI: 10.1016/0021-9169(93)90160-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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50
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Dusenbery PB, Martin RF, Burkhart GR. Particle chaos in the Earth's magnetotail. CHAOS (WOODBURY, N.Y.) 1992; 2:427-446. [PMID: 12779993 DOI: 10.1063/1.165886] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Nonlinear particle dynamics is studied both in current sheets and near neutral lines. The parameter governing particle chaos in a current sheet with a constant normal component, B(n), is kappa=(R(min)/rho(max))(1/2), where R(min) is the minimum field line radius of curvature and rho(max) is the maximum gyroradius. In such a current sheet, motion can be viewed as a combination of a component normal to the current sheet and a tangential component. The parameter kappa represents the ratio of the characteristic time scale of the normal component to the tangential, and thus, particle chaos is maximized for kappa approximately 1. For kappa<<1, the slow motion preserves the action integral of the fast motion, J(z), except near the separatrix, the phase space boundary separating motion that crosses the current sheet midplane from that which does not. Near a linear neutral line, it is found that the parameter b(n), which is the ratio of the characteristic vertical and horizontal field strengths, rather than kappa governs particle chaos. In the limit b(n)<<1, the slow motion again preserves J(z), and J(z) has the same analytic form as in a constant B(n) current sheet. In the limit of b(n)<<1, the structure of x-p(x) phase space is controlled by the stable and unstable manifolds associated with the unstable fixed point orbit at (x,p(x))=(0,0), and this structure lies along a contour of constant J(z).
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Affiliation(s)
- Paul B. Dusenbery
- Astrophysical, Planetary and Atmospheric Sciences Department, University of Colorado, Boulder, Colorado 80309-0391Physics Department, Illinois State University, Normal, Illinois 61761Astrophysical, Planetary and Atmospheric Sciences Department, University of Colorado, Boulder, Colorado 80309-0391
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