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27 results on '"EOS Space Science Center [Durham]"'

1. Statistical Relationship Between Interplanetary Magnetic Field Conditions and the Helicity Sign of Flux Transfer Event Flux Ropes

Author

N. Fargette, Barbara L. Giles, C. Jacquey, Roy Torbert, Vincent Génot, James L. Burch, Benoit Lavraud, D. J. Gershman, Aurélie Marchaudon, R. Kieokaew, Institut de recherche en astrophysique et planétologie (IRAP), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), NASA Goddard Space Flight Center (GSFC), EOS Space Science Center [Durham], University of New Hampshire (UNH), Southwest Research Institute [San Antonio] (SwRI), Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), and Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, 010504 meteorology & atmospheric sciences, [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], Astrophysics::High Energy Astrophysical Phenomena, Flux, Magnetic reconnection, 010502 geochemistry & geophysics, 01 natural sciences, Helicity, Geophysics, Quantum electrodynamics, Physics::Space Physics, General Earth and Planetary Sciences, Magnetopause, Flux transfer event, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Transient (oscillation), Interplanetary magnetic field, 0105 earth and related environmental sciences, Sign (mathematics)
Abstract

International audience; Flux transfer events (FTEs) are transient phenomena produced by magnetic reconnection at the dayside magnetopause typically under southward interplanetary magnetic field (IMF) conditions. They are usually thought of as magnetic flux ropes with helical structures forming through patchy, unsteady or multiple X-line reconnection. While the IMF often has a non-zero B_Y component, its impacts on the FTE flux rope helicity remain unknown. We survey Magnetospheric Multiscale (MMS) observations of FTE flux ropes during years 2015–2017 and investigate the solar wind conditions prior to the events. By fitting a force-free flux rope model, we select 84 events with good fits and obtain the helicity sign (i.e., handedness) of the flux ropes. We find that positive (negative) helicity flux ropes are mainly preceded by positive (negative) B_Y component. This finding is compatible with flux ropes formed through a multiple X-lines mechanism.

Published
2021

2. Observations of Particle Acceleration in Magnetic Reconnection–driven Turbulence

Author

Rumi Nakamura, S. T. Bingham, O. Le Contel, P. A. Lindqvist, Roy B. Torbert, S. Hoilijoki, Robert J. Strangeway, Lily Kromyda, Julia E. Stawarz, Robert E. Ergun, Fulvia Pucci, James L. Burch, Ian J. Cohen, Katherine Goodrich, Barbara L. Giles, D. L. Turner, Justin Holmes, Alexandros Chasapis, Frederick Wilder, Narges Ahmadi, S. J. Schwartz, Laboratory for Atmospheric and Space Physics [Boulder] (LASP), University of Colorado [Boulder], Blackett Laboratory, Imperial College London, Space Sciences Laboratory [Berkeley] (SSL), University of California [Berkeley], University of California-University of California, Johns Hopkins University Applied Physics Laboratory [Laurel, MD] (APL), Space Research Institute of Austrian Academy of Sciences (IWF), Austrian Academy of Sciences (OeAW), EOS Space Science Center [Durham], University of New Hampshire (UNH), Southwest Research Institute [San Antonio] (SwRI), Royal Institute of Technology [Stockholm] (KTH ), Institute of Geophysics and Planetary Physics [Los Angeles] (IGPP), University of California [Los Angeles] (UCLA), Laboratoire de Physique des Plasmas (LPP), Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École polytechnique (X)-Sorbonne Université (SU)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), and NASA Goddard Space Flight Center (GSFC)

Subjects
Physics, Annihilation, 010504 meteorology & atmospheric sciences, Turbulence, [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Astronomy and Astrophysics, Magnetic reconnection, Cosmic ray, Mechanics, Plasma, 01 natural sciences, Magnetic field, Particle acceleration, Space and Planetary Science, Electric field, 0103 physical sciences, 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences
Abstract

International audience

Published
2020

3. Lower-Hybrid Drift Waves Driving Electron Nongyrotropic Heating and Vortical Flows in a Magnetic Reconnection Layer

Author

Christopher T. Russell, James Drake, Per-Arne Lindqvist, Shan Wang, Levon A. Avanov, John C. Dorelli, Rumi Nakamura, Naoki Bessho, Benoit Lavraud, Jonathan Ng, Lynn B. Wilson, L. J. Chen, Kevin Genestreti, C. J. Pollock, Robert E. Ergun, Yu. V. Khotyaintsev, Roy B. Torbert, Michael Hesse, Daniel B. Graham, Thomas E. Moore, W. R. Paterson, James L. Burch, O. Le Contel, A. C. Rager, Barbara L. Giles, Department of Physics and Astronomy [Iowa City], University of Iowa [Iowa City], Laboratoire de Physique des Plasmas (LPP), Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École polytechnique (X)-Sorbonne Université (SU)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Catholic University of America, NASA Goddard Space Flight Center (GSFC), Sengkang Health, Partenaires INRAE, Space and Atmospheric Sciences Group [Los Alamos], Los Alamos National Laboratory (LANL), EOS Space Science Center [Durham], University of New Hampshire (UNH), Space Science and Engineering Division [San Antonio], Southwest Research Institute [San Antonio] (SwRI), Quantum Optics and Laser Science, Blackett Laboratory, Blackett Laboratory, Imperial College London-Imperial College London, and Royal Institute of Technology [Stockholm] (KTH )

Subjects
Physics, Field (physics), [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], General Physics and Astronomy, Magnetic reconnection, Electron dynamics, Mechanics, Electron, 01 natural sciences, Magnetic field, 0103 physical sciences, Perpendicular, Electron heating, 010306 general physics, Layer (electronics), ComputingMilieux_MISCELLANEOUS
Abstract

We report measurements of lower-hybrid drift waves driving electron heating and vortical flows in an electron-scale reconnection layer under a guide field. Electrons accelerated by the electrostatic potential of the waves exhibit perpendicular and nongyrotropic heating. The vortical flows generate magnetic field perturbations comparable to the guide field magnitude. The measurements reveal a new regime of electron-wave interaction and how this interaction modifies the electron dynamics in the reconnection layer. publishedVersion

Published
2020

4. Polynomial Reconstruction of the Reconnection Magnetic Field Observed by Multiple Spacecraft

Author

Denton, R. E., Torbert, R. B., Dors, I., Genestreti, K. J., Argall, M., Gershman, D. J., Le, Contel O., Burch, J. L., Russell, C. T., Strangeway, R. J., Giles, B. L., Fischer, D., Hasegawa, Hiroshi, University of New Hampshire (UNH), Laboratoire des sciences et matériaux pour l'électronique et d'automatique (LASMEA), Université Blaise Pascal - Clermont-Ferrand 2 (UBP)-Centre National de la Recherche Scientifique (CNRS), EOS Space Science Center [Durham], Laboratoire de Physique des Plasmas (LPP), Université Paris-Saclay-Sorbonne Université-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11)-École polytechnique (X)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU), Southwest Research Institute [San Antonio] (SwRI), Department of Earth, Planetary and Space Sciences [Los Angeles] (EPSS), University of California [Los Angeles] (UCLA), University of California-University of California, Institute of Geophysics and Planetary Physics [Los Angeles] (IGPP), Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École polytechnique (X)-Sorbonne Université (SU)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, Polynomial, 010504 meteorology & atmospheric sciences, Spacecraft, business.industry, [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Magnetic reconnection, Plasmoid, 01 natural sciences, Magnetic field, Computational physics, Geophysics, Space and Planetary Science, 0103 physical sciences, business, 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences
Abstract

著者人数: 13名, Accepted: 2019-12-11, 資料番号: SA1190210000

Published
2020

5. Electron‐Scale Magnetic Structure Observed Adjacent to an Electron Diffusion Region at the Dayside Magnetopause

Author

S. Hoilijoki, O. Le Contel, Narges Ahmadi, Robert J. Strangeway, James Webster, Frederick Wilder, Barbara L. Giles, Roy B. Torbert, James L. Burch, S. J. Schwartz, Stefan Eriksson, Robert E. Ergun, Laboratory for Atmospheric and Space Physics [Boulder] (LASP), University of Colorado [Boulder], Networking Research Center on Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), Alfven Laboratory, Royal Institute of Technology [Stockholm] (KTH ), Laboratoire de Physique des Plasmas (LPP), Université Paris-Saclay-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11)-École polytechnique (X)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Space Science Division [San Antonio], Southwest Research Institute [San Antonio] (SwRI), EOS Space Science Center [Durham], University of New Hampshire (UNH), Institute of Geophysics and Planetary Physics [Los Angeles] (IGPP), University of California [Los Angeles] (UCLA), University of California-University of California, and NASA Headquarters

Subjects
Physics, 010504 meteorology & atmospheric sciences, Scale (ratio), Magnetic structure, [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Electron, 01 natural sciences, Computational physics, Geophysics, Space and Planetary Science, 0103 physical sciences, Magnetopause, Diffusion (business), 010306 general physics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences
Abstract

International audience

Published
2019

6. Magnetic Reconnection in Three Dimensions: Modeling and Analysis of Electromagnetic Drift Waves in the Adjacent Current Sheet

Author

Michael Shay, Julia E. Stawarz, S. Hoilijoki, Frederick Wilder, Stefan Eriksson, Steven J. Schwartz, Paul Cassak, Katherine Goodrich, Roy B. Torbert, Hantao Ji, Michael Hesse, Robert E. Ergun, James L. Burch, Robert J. Strangeway, Masaaki Yamada, Justin Holmes, M. Swisdak, James Drake, Daniel B. Graham, O. LeContel, Narges Ahmadi, Laboratory for Atmospheric and Space Physics [Boulder] (LASP), University of Colorado [Boulder], Code 696, NASA Goddard Space Flight Center (GSFC), Department of Physics [Haifa], Technion - Israel Institute of Technology [Haifa], H. H. Wills Physics Laboratory [Bristol], University of Bristol [Bristol], Swedish Institute of Space Physics [Uppsala] (IRF), Space Science Division [San Antonio], Southwest Research Institute [San Antonio] (SwRI), EOS Space Science Center [Durham], University of New Hampshire (UNH), Alfven Laboratory, Royal Institute of Technology [Stockholm] (KTH ), Institute of Geophysics and Planetary Physics [Los Angeles] (IGPP), University of California [Los Angeles] (UCLA), University of California-University of California, Laboratoire de Physique des Plasmas (LPP), Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École polytechnique (X)-Sorbonne Université (SU)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, 010504 meteorology & atmospheric sciences, Turbulence, [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Magnetic reconnection, Geophysics, 01 natural sciences, Current sheet, Space and Planetary Science, Physics::Space Physics, Astrophysics::Solar and Stellar Astrophysics, Magnetopause, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences
Abstract

We present a model of electromagnetic drift waves in the current sheet adjacent to magnetic reconnection at the subsolar magnetopause. These drift waves are potentially important in governing 3‐D structure of subsolar magnetic reconnection and in generating turbulence. The drift waves propagate nearly parallel to the X line and are confined to a thin current sheet. The scale size normal to the current sheet is significantly less than the ion gyroradius and can be less than or on the order of the wavelength. The waves also have a limited extent along the magnetic field (B), making them a three‐dimensional eigenmode structure. In the current sheet, the background magnitudes of B and plasma density change significantly, calling for a treatment that incorporates an inhomogeneous plasma environment. Using detailed examination of Magnetospheric Multiscale observations, we find that the waves are best represented by series of electron vortices, superimposed on a primary electron drift, that propagate along the current sheet (parallel to the X line). The waves displace or corrugate the current sheet, which also potentially displaces the electron diffusion region. The model is based on fluid behavior of electrons, but ion motion must be treated kinetically. The strong electron drift along the X line is likely responsible for wave growth, similar to a lower hybrid drift instability. Contrary to a classical lower hybrid drift instability, however, the strong changes in the background B and no, the normal confinement to the current sheet, and the confinement along B are critical to the wave description. publishedVersion

Published
2019

7. Electron Scattering by Low-frequency Whistler Waves at Earth’s Bow Shock

Author

Christopher T. Russell, Mitsuo Oka, Shuichi Matsukiyo, T. D. Phan, Per-Arne Lindqvist, Matthew R. Argall, John C. Dorelli, Barbara L. Giles, Roy B. Torbert, Robert E. Ergun, Lynn B. Wilson, Fumiko Otsuka, O. Le Contel, Masahiro Hoshino, Takanobu Amano, D. J. Gershman, James L. Burch, Research Institute for Sustainable Humanosphere (RISH), Kyoto University [Kyoto], Max-Planck-Institut für Extraterrestrische Physik (MPE), Space Sciences Laboratory [Berkeley] (SSL), University of California [Berkeley], University of California-University of California, Laboratoire de Physique des Plasmas (LPP), Université Paris-Saclay-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11)-École polytechnique (X)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Space Science Division [San Antonio], Southwest Research Institute [San Antonio] (SwRI), EOS Space Science Center [Durham], University of New Hampshire (UNH), NASA Headquarters, Laboratory for Atmospheric and Space Physics [Boulder] (LASP), University of Colorado [Boulder], Department of Earth, Planetary and Space Sciences [Los Angeles] (EPSS), and University of California [Los Angeles] (UCLA)

Subjects
Shock wave, Physics, 010504 meteorology & atmospheric sciences, Whistler, business.industry, [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Cyclotron resonance, Astronomy and Astrophysics, Electron, 01 natural sciences, Computational physics, Shock waves in astrophysics, Optics, Space and Planetary Science, Bow wave, 0103 physical sciences, Physics::Accelerator Physics, Bow shock (aerodynamics), business, 010303 astronomy & astrophysics, Electron scattering, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences
Abstract

Electrons are accelerated to non-thermal energies at shocks in space and astrophysical environments. While different mechanisms of electron acceleration have been proposed, it remains unclear how n ...

Published
2019

8. A Survey of Plasma Waves Appearing Near Dayside Magnetopause Electron Diffusion Region Events

Author

S. Hoilijoki, O. Le Contel, Barbara L. Giles, Matthew R. Argall, Narges Ahmadi, Robert E. Ergun, James Webster, Robert J. Strangeway, Stefan Eriksson, Roy B. Torbert, Frederick Wilder, James L. Burch, Laboratory for Atmospheric and Space Physics [Boulder] (LASP), University of Colorado [Boulder], Alfven Laboratory, Royal Institute of Technology [Stockholm] (KTH ), Space Science Division [San Antonio], Southwest Research Institute [San Antonio] (SwRI), EOS Space Science Center [Durham], University of New Hampshire (UNH), Laboratoire de Physique des Plasmas (LPP), Université Paris-Saclay-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11)-École polytechnique (X)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Institute of Geophysics and Planetary Physics [Los Angeles] (IGPP), University of California [Los Angeles] (UCLA), University of California-University of California, and NASA Headquarters

Subjects
Physics, 010504 meteorology & atmospheric sciences, [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Plasma, Electron, 01 natural sciences, Molecular physics, Geophysics, Space and Planetary Science, 0103 physical sciences, Magnetopause, Diffusion (business), 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences
Abstract

International audience

Published
2019

9. Kinetic Turbulence in Astrophysical Plasmas: Waves and/or Structures?

Author

Daniel Grošelj, Christopher H. K. Chen, Frank Jenko, Ravi Samtaney, Alfred Mallet, Kai Schneider, EOS Space Science Center [Durham], University of New Hampshire (UNH), King Abdullah University of Science and Technology (KAUST), Institut de Mathématiques de Marseille (I2M), Centre National de la Recherche Scientifique (CNRS)-École Centrale de Marseille (ECM)-Aix Marseille Université (AMU), Max-Planck-Institut für Plasmaphysik [Garching] (IPP), Queen Mary University of London (QMUL), Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS), Science and Technology Facilities Council (STFC), Ernest Rutherford Fellowship, National Science Foundation (NSF) Grant No. AGS-1624501, OSIRIS Consortium, consisting of UCLA and IST (Lisbon, Portugal), and European Project: 25887,EFDA

Subjects
[PHYS.PHYS.PHYS-FLU-DYN]Physics [physics]/Physics [physics]/Fluid Dynamics [physics.flu-dyn], QC1-999, Wave packet, FOS: Physical sciences, General Physics and Astronomy, Kinetic energy, 01 natural sciences, 010305 fluids & plasmas, Physics - Space Physics, [PHYS.PHYS.PHYS-PLASM-PH]Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph], [MATH.MATH-ST]Mathematics [math]/Statistics [math.ST], 0103 physical sciences, [NLIN]Nonlinear Sciences [physics], 010306 general physics, Anisotropy, Solar and Stellar Astrophysics (astro-ph.SR), ComputingMilieux_MISCELLANEOUS, Physics, Turbulence, Plasma, [PHYS.ASTR.SR]Physics [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Space Physics (physics.space-ph), [PHYS.PHYS.PHYS-SPACE-PH]Physics [physics]/Physics [physics]/Space Physics [physics.space-ph], Physics - Plasma Physics, Computational physics, Plasma Physics (physics.plasm-ph), Solar wind, Amplitude, Astrophysics - Solar and Stellar Astrophysics, Physics::Space Physics, Astrophysical plasma
Abstract

The question of the relative importance of coherent structures and waves has for a long time attracted a great deal of interest in astrophysical plasma turbulence research, with a more recent focus on kinetic scale dynamics. Here we utilize high-resolution observational and simulation data to investigate the nature of waves and structures emerging in a weakly collisional, turbulent kinetic plasma. Observational results are based on in situ solar wind measurements from the Cluster and MMS spacecraft, and the simulation results are obtained from an externally driven, three-dimensional fully kinetic simulation. Using a set of novel diagnostic measures we show that both the large-amplitude structures and the lower-amplitude background fluctuations preserve linear features of kinetic Alfven waves to order unity. This quantitative evidence suggests that the kinetic turbulence cannot be described as a mixture of mutually exclusive waves and structures but may instead be pictured as an ensemble of localized, anisotropic wave packets or "eddies" of varying amplitudes, which preserve certain linear wave properties during their nonlinear evolution., Revised and extended version; accepted for publication in Phys. Rev. X

Published
2019

10. Mass Loading the Earth's Dayside Magnetopause Boundary Layer and Its Effect on Magnetic Reconnection

Author

Paul Tenfjord, Robert J. Strangeway, Daniel B. Graham, Stein Haaland, Thomas E. Moore, S. A. Fuselier, Benoit Lavraud, Michael Hesse, Wenya Li, James L. Burch, Sarah K. Vines, K. J. Trattner, Jérémy Dargent, S. M. Petrinec, Mats André, Katariina Nykyri, Alex Glocer, Sergio Toledo-Redondo, C. R. Chappell, L. M. Kistler, Michael H. Denton, N. Aunai, L. Alm, Lockheed Martin Advanced Technology Center (ATC), European Space Agency (ESA), Swedish Institute of Space Physics [Uppsala] (IRF), Laboratoire de Physique des Plasmas (LPP), Université Paris-Saclay-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11)-École polytechnique (X)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Max-Planck-Institut für Extraterrestrische Physik (MPE), NASA Goddard Space Flight Center (GSFC), EOS Space Science Center [Durham], University of New Hampshire (UNH), Institut de recherche en astrophysique et planétologie (IRAP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), CFD Lab [Montréal], Department of Mechanical Engineering [Montréal], McGill University = Université McGill [Montréal, Canada]-McGill University = Université McGill [Montréal, Canada], Agence Spatiale Européenne = European Space Agency (ESA), Université Paris-Sud - Paris 11 (UP11)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École polytechnique (X)-Sorbonne Université (SU)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, 010504 meteorology & atmospheric sciences, Field line, [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], Magnetic reconnection, 010502 geochemistry & geophysics, 01 natural sciences, Computational physics, Magnetic field, Boundary layer, Geophysics, Magnetosheath, Physics::Plasma Physics, Physics::Space Physics, General Earth and Planetary Sciences, Magnetopause, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Ionosphere, Interplanetary magnetic field, 0105 earth and related environmental sciences
Abstract

International audience; When the interplanetary magnetic field is northward for a period of time, O + from the high-latitude ionosphere escapes along reconnected magnetic field lines into the dayside magnetopause boundary layer. Dual-lobe reconnection closes these field lines, which traps O + and mass loads the boundary layer. This O + is an additional source of magnetospheric plasma that interacts with magnetosheath plasma through magnetic reconnection. This mass loading and interaction is illustrated through analysis of a magnetopause crossing by the Magnetospheric Multiscale spacecraft. While in the O +-rich boundary layer, the interplanetary magnetic field turns southward. As the Magnetospheric Multiscale spacecraft cross the high-shear magnetopause, reconnection signatures are observed. While the reconnection rate is likely reduced by the mass loading, reconnection is not suppressed at the magnetopause. The high-latitude dayside ionosphere is therefore a source of magnetospheric ions that contributes often to transient reduction in the reconnection rate at the dayside magnetopause.

Published
2019

11. Observations of Flux Ropes With Strong Energy Dissipation in the Magnetotail

Author

Yuri V. Khotyaintsev, James L. Burch, D. Deng, L. H. He, Huishan Fu, K. Jiang, Xiongdong Yu, Zhigang Yuan, Fouad Sahraoui, Roy B. Torbert, Xin-Fa Deng, Craig J. Pollock, Shiyong Huang, Meng Zhou, School of Electronic Information [Wuhan], Wuhan University [China], Laboratoire de Physique des Plasmas (LPP), Université Paris-Saclay-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11)-École polytechnique (X)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Beihang University (BUAA), Swedish Institute of Space Physics [Uppsala] (IRF), NASA Goddard Space Flight Center (GSFC), EOS Space Science Center [Durham], University of New Hampshire (UNH), and Southwest Research Institute [San Antonio] (SwRI)

Subjects
Physics, 010504 meteorology & atmospheric sciences, Astrophysics::High Energy Astrophysical Phenomena, Flux, Magnetic reconnection, [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph], Electron, Dissipation, 010502 geochemistry & geophysics, 01 natural sciences, Computational physics, Vortex, Geophysics, Physics::Space Physics, General Earth and Planetary Sciences, Astrophysics::Solar and Stellar Astrophysics, Electron flow, 0105 earth and related environmental sciences, Rope
Abstract

International audience; An ion-scale flux rope (FR), embedded in a high-speed electron flow (possibly an electron vortex), is investigated in the magnetotail using observations from the Magnetospheric Multiscale (MMS) spacecraft. Intense electric field and current and abundant waves are observed in the exterior and interior regions of the FR. Comparable parallel and perpendicular currents in the interior region imply that the FR has a non-force-free configuration. Electron demagnetization occurs in some subregions of the FR. It is surprising that strong dissipation (J × E' up to 2,000 pW/m 3) occurs in the center of the FR without signatures of secondary reconnection or coalescence of two FRs, implying that FR may provide another important channel for energy dissipation in space plasmas. These features indicate that the observed FR is still highly dynamical, and hosts multiscale coupling processes, even though the FR has a very large scale and is far away from the reconnection site. Plain Language Summary Flux ropes, 3-D helical magnetic structures, in which magnetic field lines twist with each other, play an important role in the macroscopic and microscopic physical process during magnetic reconnection. Most of previous studies focused on the flux ropes in the reconnection region. However, some physical process inside macroscopic flux ropes far away from the reconnection site in the magnetotail is still unclear due to the lack of high time resolution data. In this letter, thanks to the unprecedented high time resolution data of the Magnetospheric Multiscale (MMS) mission, we report an ion-scale flux rope and study its dynamics. Our observations demonstrate that the observed flux rope is still highly dynamical, and hosting multiscale coupling processes and strong energy dissipation, even though the flux rope has very large scale and is far away from the reconnection site.

Published
2019

12. Electron Diffusion Regions in Magnetotail Reconnection Under Varying Guide Fields

Author

James L. Burch, O. Le Contel, Shan Wang, Naoki Bessho, Thomas E. Moore, Robert J. Strangeway, Per-Arne Lindqvist, Yu. V. Khotyaintsev, W. R. Paterson, L. J. Chen, Barbara L. Giles, Michael Hesse, C. J. Pollock, Roy B. Torbert, Christopher T. Russell, Kevin Genestreti, Robert E. Ergun, Benoit Lavraud, NASA Goddard Space Flight Center (GSFC), University of Maryland [College Park], University of Maryland System, University of Bergen (UiB), Laboratory for Atmospheric and Space Physics [Boulder] (LASP), University of Colorado [Boulder], University of California [Los Angeles] (UCLA), University of California, Southwest Research Institute [San Antonio] (SwRI), EOS Space Science Center [Durham], University of New Hampshire (UNH), Denali Scientific, Institut de recherche en astrophysique et planétologie (IRAP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique des Plasmas (LPP), Université Paris-Saclay-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11)-École polytechnique (X)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Institute of Geophysics and Planetary Physics [Los Angeles] (IGPP), University of California-University of California, Swedish Institute of Space Physics [Uppsala] (IRF), Royal Institute of Technology [Stockholm] (KTH ), University of California (UC), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Université Paris-Sud - Paris 11 (UP11)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École polytechnique (X)-Sorbonne Université (SU)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), and University of California (UC)-University of California (UC)

Subjects
Physics, education.field_of_study, 010504 meteorology & atmospheric sciences, Field (physics), Population, [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph], Electron, 010502 geochemistry & geophysics, Kinetic energy, Fusion, Plasma and Space Physics, 01 natural sciences, Computational physics, Magnetic field, Fusion, plasma och rymdfysik, Current sheet, Geophysics, Physics::Space Physics, Perpendicular, General Earth and Planetary Sciences, Diffusion (business), education, 0105 earth and related environmental sciences
Abstract

Kinetic structures of electron diffusion regions (EDRs) under finite guide fields in magnetotail reconnection are reported. The EDRs with guide fields 0.14-0.5 (in unit of the reconnecting component) are detected by the Magnetospheric Multiscale spacecraft. The key new features include the following: (1) cold inflowing electrons accelerated along the guide field and demagnetized at the magnetic field minimum while remaining a coherent population with a low perpendicular temperature, (2) wave fluctuations generating strong perpendicular electron flows followed by alternating parallel flows inside the reconnecting current sheet under an intermediate guide field, and (3) gyrophase bunched electrons with high parallel speeds leaving the X-line region. The normalized reconnection rates for the three EDRs range from 0.05 to 0.3. The measurements reveal that finite guide fields introduce new mechanisms to break the electron frozen-in condition. Plain Language Summary Magnetic reconnection plays a crucial role in the dynamics of the terrestrial magnetotail. For reconnection to occur, the plasma must decouple from the magnetic field. The bounce motion of particles in the magnetotail current sheet is regarded as a key to this decoupling for cases when the current sheet has no magnetic field along the direction of the current. This paper reports that while bounce motion remains relevant when a finite magnetic field is present along the current, new mechanisms to decouple electrons from the magnetic field are introduced, and new open questions unfold. The observations are based on measurements from the Magnetospheric Multiscale mission. The mission's unprecedented high cadence electron data make possible the revelation of the new mechanisms. The results reported in this paper expand the frontiers of our knowledge on magnetotail reconnection and have major implications on the fundamental physics of magnetic reconnection in all plasma systems where binary collisions are not effective, including solar, astrophysical, and laboratory plasmas. Rapid dissemination of the results will set the ground for advances in magnetic reconnection research.

Published
2019

13. Magnetic Reconnection in Three Dimensions : Observations of Electromagnetic Drift Waves in the Adjacent Current Sheet

Author

Katherine Goodrich, James L. Burch, Steven J. Schwartz, Frederick Wilder, Julia E. Stawarz, Robert E. Ergun, Justin Holmes, S. Hoilijoki, D. J. Gershman, Roy B. Torbert, Stefan Eriksson, Daniel B. Graham, Narges Ahmadi, Robert J. Strangeway, L. J. Chen, P. A. Lindqvist, Barbara L. Giles, O. Le Contel, Laboratory for Atmospheric and Space Physics [Boulder] (LASP), University of Colorado [Boulder], Networking Research Center on Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), Space Science Division [San Antonio], Southwest Research Institute [San Antonio] (SwRI), EOS Space Science Center [Durham], University of New Hampshire (UNH), Institute of Geophysics and Planetary Physics [Los Angeles] (IGPP), University of California [Los Angeles] (UCLA), University of California-University of California, Laboratoire de Physique des Plasmas (LPP), Université Paris-Saclay-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11)-École polytechnique (X)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Alfven Laboratory, Royal Institute of Technology [Stockholm] (KTH ), and NASA Goddard Space Flight Center (GSFC)

Subjects
010504 meteorology & atmospheric sciences, [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], drift waves, 01 natural sciences, Current sheet, Fusion, plasma och rymdfysik, Astronomi, astrofysik och kosmologi, Physics::Plasma Physics, Electric field, Astrophysics::Solar and Stellar Astrophysics, Astronomy, Astrophysics and Cosmology, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Plasma density, Physics, Condensed matter physics, Geofysik, Turbulence, parallel electric fields, turbulence, Magnetic reconnection, Fusion, Plasma and Space Physics, Magnetic field, Geophysics, Space and Planetary Science, magnetic reconnection, Physics::Space Physics, Magnetopause
Abstract

Magnetic reconnection at the subsolar magnetopause is persistently accompanied by strong fluctuations of the magnetic field (B), plasma density (n), and all components of the electric field (E) and current (J). The strongest fluctuations are at frequencies below the lower hybrid frequency and observed in a thin, intense current sheet adjacent to the electron diffusion region. In this current sheet, the background magnitudes of B and n are changing considerably, creating an inhomogeneous plasma environment. We show that the fluctuations in B and n are consistent with an oscillatory displacement of the current sheet in the surface normal direction. The displacement is propagating parallel to the magnetic reconnection X line. Wavelengths are on the order of or longer than the thickness of the current sheet to which they are confined, so we label these waves electromagnetic drift waves. E and J fluctuations are more complex than a simple displacement. They have significant variations in the component along B, which suggest that the drift waves also may be confined along B. The current sheet is supported by an electron drift driven by normal electric field, which, in turn, is balanced by an ion pressure gradient. We suggest that wave growth comes from an instability related to the drift between the electrons and ions. We discuss the possibility that drift waves can displace or penetrate into the electron diffusion region giving magnetic reconnection three-dimensional structure. Drift waves may corrugate the X line, possibly breaking the X line and generating turbulence.

Published
2019

14. Space Physics Effects in the Near-Magnetopause Magnetosheath Elicited by Large-Amplitude Alfvénic Fluctuations Terminating in a Field and Flow Discontinuity

Author

Farrugia, C., Cohen, I, Vasquez, B, Lugaz, N, Alm, L, Torbert, R., Argall, M, Paulson, K, Lavraud, B, Gershman, D, Gratton, F, Matsui, H, Rogers, A, Forbes, T, Payne, D, Ergun, R, Mauk, B, Burch, J, Russell, C, Strangeway, R, Shuster, J, Nakamura, R, Fuselier, S, Giles, B, Khotyaintsev, Y, Lindqvist, P, Marklund, G, Petrinec, S, Pollock, C, Laboratoire de Parasitologie-Mycologie, Assistance publique - Hôpitaux de Paris (AP-HP) (AP-HP)-Hôpital Henri Mondor-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12), EOS Space Science Center [Durham], and University of New Hampshire (UNH)

Subjects
[PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Physics::Space Physics
Abstract

International audience; In this paper we report on a sequence of large-amplitude Alfvénic fluctuations terminating in a field and flow discontinuity and their effects on electromagnetic fields and plasmas in the near-magnetopause magnetosheath. An arc-polarized structure in the magnetic field was observed by the Time History of Events and Macroscale Interactions during Substorms-C in the solar wind, indicative of nonlinear Alfvén waves. It ends with a combined tangential discontinuity/vortex sheet, which is strongly inclined to the ecliptic plane and at which there is a sharp rise in the density and a drop in temperature. Several effects resulting from this structure were observed by the Magnetospheric Multiscale spacecraft in the magnetosheath close to the subsolar point (11:30 magnetic local time) and somewhat south of the geomagnetic equator (−33 ∘ magnetic latitude): (i) kinetic Alfvén waves; (ii) a peaking of the electric and magnetic field strengths where E ⋅ J becomes strong and negative (−1 nW/m 3) just prior to an abrupt dropout of the fields; (iii) evolution in the pitch angle distribution of energetic (a few tens of kilo-electron-volts) ions (H + , He n+ , and O n+) and electrons inside a high-density region, which we attribute to gyrosounding of the tangential discontinuity/vortex sheet structure passing by the spacecraft; (iv) field-aligned acceleration of ions and electrons that could be associated with localized magnetosheath reconnection inside the high-density region; and (v) variable and strong flow changes, which we argue to be unrelated to reconnection at partial magnetopause crossings and likely result from deflections of magnetosheath flow by a locally deformed, oscillating magnetopause.

Published
2018

15. Small-scale flux transfer events formed in the reconnection exhaust region between two X lines

Author

Barbara L. Giles, David G. Sibeck, Robert J. Strangeway, Christopher T. Russell, Huishan Fu, James L. Burch, Levon A. Avanov, Craig J. Pollock, John C. Dorelli, W. R. Paterson, Robert E. Ergun, D. J. Gershman, Philippe Escoubet, Roy B. Torbert, Yuri V. Khotyaintsev, Jonathan Eastwood, Sergio Toledo-Redondo, Eunjin Choi, Benoit Lavraud, Robert Fear, Kyoung-Joo Hwang, Science and Technology Facilities Council (STFC), Institut de recherche en astrophysique et planétologie (IRAP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), NASA Headquarters, NASA Goddard Space Flight Center (GSFC), European Space Agency (ESA), EOS Space Science Center [Durham], University of New Hampshire (UNH), Laboratory for Atmospheric and Space Physics [Boulder] (LASP), University of Colorado [Boulder], Department of Earth, Planetary and Space Sciences [Los Angeles] (EPSS), University of California [Los Angeles] (UCLA), University of California-University of California, Institute of Geophysics and Planetary Physics [Los Angeles] (IGPP), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Agence Spatiale Européenne = European Space Agency (ESA), and University of California (UC)-University of California (UC)

Subjects
Physics, 010504 meteorology & atmospheric sciences, [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], Flux, 01 natural sciences, Pressure-gradient force, Instability, [PHYS.PHYS.PHYS-SPACE-PH]Physics [physics]/Physics [physics]/Space Physics [physics.space-ph], Magnetic field, Computational physics, Geophysics, Flow velocity, Space and Planetary Science, 0103 physical sciences, Flux transfer event, Magnetopause, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Line (formation)
Abstract

International audience; We report MMS observations of the ion-scale flux transfer events (FTEs) that may involve two main X lines and tearing instability between the two X lines. The four spacecraft detected multiple isolated regions with enhanced magnetic field strength and bipolar B n signatures normal to the nominal magnetopause, indicating FTEs. The currents within the FTEs flow mostly parallel to B, and the magnetic tension force is balanced by the total pressure gradient force. During these events, the plasma bulk flow velocity was directed southward. Detailed analysis of the magnetic and electric field and plasma moments variations suggests that the FTEs were initially embedded within the exhaust region north of an X line but were later located southward/downstream of a subsequent X line. The cross sections of the individual FTEs are in the range of~2.5-6.8 ion inertial lengths. The observations suggest the formation of multiple secondary FTEs. The presence of an X line in the exhaust region southward of a second X line results from the southward drift of an old X line and the reformation of a new X line. The current layer between the two X lines is unstable to the tearing instability, generating multiple ion-scale flux-rope-type secondary islands.

Published
2018

16. Detailed dayside auroral morphology as a function of local time for southeast IMF orientation: implications for solar wind-magnetosphere coupling

Author

Per Even Sandholt, Charlie J. Farrugia, William Denig, EGU, Publication, Department of Physics, Okayama University, EOS Space Science Center [Durham], University of New Hampshire (UNH), AFRL Space Vehicles Directorate, Air Force Research Laboratory (AFRL), and United States Air Force (USAF)-United States Air Force (USAF)

Subjects
Atmospheric Science, 010504 meteorology & atmospheric sciences, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, Magnetosphere, Subsolar point, 01 natural sciences, Magnetosheath, 0103 physical sciences, Earth and Planetary Sciences (miscellaneous), Interplanetary magnetic field, lcsh:Science, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Physics, [SDU.OCEAN] Sciences of the Universe [physics]/Ocean, Atmosphere, lcsh:QC801-809, Plasma sheet, Geology, Astronomy and Astrophysics, Geophysics, lcsh:QC1-999, lcsh:Geophysics. Cosmic physics, Solar wind, 13. Climate action, Space and Planetary Science, [SDU.STU] Sciences of the Universe [physics]/Earth Sciences, Magnetopause, lcsh:Q, Ionosphere, lcsh:Physics
Abstract

In two case studies we elaborate on spatial and temporal structures of the dayside aurora within 08:00-16:00 magnetic local time (MLT) and discuss the relationship of this structure to solar wind-magnetosphere interconnection topology and the different stages of evolution of open field lines in the Dungey convection cycle. The detailed 2-D auroral morphology is obtained from continuous ground observations at Ny Ålesund (76° magnetic latitude (MLAT)), Svalbard during two days when the interplanetary magnetic field (IMF) is directed southeast (By>0; Bz). The auroral activity consists of the successive activations of the following forms: (i) latitudinally separated, sunward moving, arcs/bands of dayside boundary plasma sheet (BPS) origin, in the prenoon (08:00-11:00MLT) and postnoon (12:00-16:00MLT) sectors, within 70-75° MLAT, (ii) poleward moving auroral forms (PMAFs) emanating from the pre- and postnoon brightening events, and (iii) a specific activity appearing in the 07:00-10:00MLT/75-80° MLAT during the prevailing IMF By>0 conditions. The pre- and postnoon activations are separated by a region of strongly attenuated auroral activity/intensity within the 11:00-12:00MLT sector, often referred to as the midday gap aurora. The latter aurora is attributed to the presence of component reconnection at the subsolar magnetopause where the stagnant magnetosheath flow lead to field-aligned currents (FACs) which are of only moderate intensity. The much more active and intense aurorae in the prenoon (07:00-11:00MLT) and postnoon (12:00-16:00MLT) sectors originate in magnetopause reconnection events that are initiated well away from the subsolar point. The high-latitude auroral activity in the prenoon sector (feature iii) is found to be accompanied by a convection channel at the polar cap boundary. The associated ground magnetic deflection (DPY) is a Svalgaard-Mansurov effect. The convection channel is attributed to effective momentum transfer from the solar wind-magnetosphere dynamo in the high-latitude boundary layer (HBL), on the downstream side of the cusp.

Published
2018

17. Characteristics of merging at the magnetopause inferred from dayside 557.7-nm all-sky images: IMF drivers of poleward moving auroral forms

Author

N. C. Maynard, W. J. Burke, Y. Ebihara, D. M. Ober, G. R. Wilson, K. D. Siebert, J. D. Winningham, L. J. Lanzerotti, C. J. Farrugia, M. Ejiri, H. Rème, A. Balogh, A. Fazakerley, EOS Space Science Center [Durham], University of New Hampshire (UNH), Air Force Research Laboratory (AFRL), United States Air Force (USAF), National Institute of Polar Research [Tokyo] (NiPR), ATK Mission Research, Department of Space Studies [Boulder], Southwest Research Institute [Boulder] (SwRI), New Jersey Institute of Technology [Newark] (NJIT), Centre d'étude spatiale des rayonnements (CESR), Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées, Imperial College London, Mullard Space Science Laboratory (MSSL), University College of London [London] (UCL), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)

Subjects
Atmospheric Science, 010504 meteorology & atmospheric sciences, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, Magnetosphere, Interplanetary medium, 01 natural sciences, 010305 fluids & plasmas, 0103 physical sciences, Earth and Planetary Sciences (miscellaneous), Interplanetary magnetic field, lcsh:Science, 0105 earth and related environmental sciences, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, lcsh:QC801-809, Northern Hemisphere, Geology, Astronomy and Astrophysics, Geophysics, lcsh:QC1-999, Solar wind, lcsh:Geophysics. Cosmic physics, 13. Climate action, Space and Planetary Science, Magnetopause, Light emission, lcsh:Q, Interplanetary spaceflight, lcsh:Physics
Abstract

We combine in situ measurements from Cluster with high-resolution 557.7 nm all-sky images from South Pole to investigate the spatial and temporal evolution of merging on the dayside magnetopause. Variations of 557.7 nm emissions were observed at a 6 s cadence at South Pole on 29 April 2003 while significant changes in the Interplanetary Magnetic Field (IMF) clock angle were reaching the magnetopause. Electrons energized at merging sites are the probable sources for 557.7 nm cusp emissions. At the same time Cluster was crossing the pre-noon cusp in the Northern Hemisphere. The combined observations confirm results of a previous study that merging events can occur at multiple sites simultaneously and vary asynchronously on time scales of 10 s to 3 min (Maynard et al., 2004). The intensity of the emissions and the merging rate appear to vary with changes in the IMF clock angle, IMF BX and the dynamic pressure of the solar wind. Most poleward moving auroral forms (PMAFs) reflect responses to changes in interplanetary medium rather than to local processes. The changes in magnetopause position required by increases in dynamic pressure are mediated by merging and result in the generation of PMAFs. Small (15–20%) variations in dynamic pressure of the solar wind are sufficient to launch PMAFs. Changes in IMF BX create magnetic flux compressions and rarefactions in the solar wind. Increases (decreases) in IMF BX strengthens |B| near northern (southern) hemisphere merging sites thereby enhancing merging rates and triggering PMAFs. When correlating responses in the two hemispheres, the presence of significant IMF BX also requires that different lag-times be applied to ACE measurements acquired ~0.1 AU upstream of Earth. Cluster observations set lag times for merging at Northern Hemisphere sites; post-noon optical emissions set times of Southern Hemisphere merging. All-sky images and magnetohydrodynamic simulations indicate that merging occurs in multiple discrete locations, rather than continuously, across the dayside for southward IMF conditions in the presence of dipole tilt. Matching optical signatures with clock-angle, BX, and dynamic pressure variations provides new insights about interplanetary control of dayside merging and associated auroral dynamics.

Published
2006

18. Cluster observations of bounday layer structure and a flux transfer event near the cusp

Author

Henri Rème, E. A. Lucek, A. D. Lahiff, C. G. Mouikis, Christopher J. Owen, André Balogh, Robert Fear, L. M. Kistler, Andrew Fazakerley, Mullard Space Science Laboratory (MSSL), University College of London [London] (UCL), Blackett Laboratory, Imperial College London, EOS Space Science Center [Durham], University of New Hampshire (UNH), Centre d'étude spatiale des rayonnements (CESR), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), and Université Fédérale Toulouse Midi-Pyrénées

Subjects
Atmospheric Science, 010504 meteorology & atmospheric sciences, Magnetosphere, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, Astrophysics, 01 natural sciences, Magnetosheath, 0103 physical sciences, Earth and Planetary Sciences (miscellaneous), Interplanetary magnetic field, lcsh:Science, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Physics, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Spacecraft, business.industry, lcsh:QC801-809, Geology, Astronomy and Astrophysics, Geophysics, lcsh:QC1-999, Solar wind, Boundary layer, lcsh:Geophysics. Cosmic physics, Space and Planetary Science, Physics::Space Physics, Flux transfer event, Magnetopause, lcsh:Q, business, lcsh:Physics
Abstract

On the 25th January 2002 between 10:00 and 12:00UT, the four Cluster spacecraft passed through the northern high-latitude cusp, the dayside magnetosphere and into the magnetosheath in a linear formation. In the magnetosphere the PEACE electron spectrometers on the four spacecraft all observed a series of transient bursts of magnetosheath-like plasma, but without bipolar magnetic signatures in the magnetopause normal component as might be expected if the plasma had been injected by transient reconnection (flux transfer events – FTEs). Reordering the data using the magnetopause transition parameter reveals that these plasma observations, the related variations in the magnetic field and the balance of magnetic and thermal gas pressures are consistent with transient entries into a stable high-latitude boundary layer structure. However, once some of the spacecraft entered the magnetosheath, FTE signatures were observed outside the magnetopause at the same time as some of the boundary layer entries occurred at the other spacecraft inside. Thus, (a) the lack of a bipolar BN signature is inconsistent with the traditional picture of a magnetospheric FTE, and (b) the cause of the observed entry of the spacecraft into the boundary layer (pressure pulse or passing magnetosheath FTE) can only be determined by spacecraft observations in the magnetosheath. Keywords. Magnetospheric physics (Magnetopause, cusp and bondary layers; Solar wind- magnetosphere interactions; Magnetosheath)

Published
2005

19. Survey of energetic O+ ions near the dayside mid-latitude magnetopause with Cluster

Author

Bouhram, M., Klecker, B., Paschmann, G., Haaland, S., Hasegawa, H., Blagau, A., Rème, H., Sauvaud, J.-A., Kistler, L. M., Balogh, A., Max-Planck-Institut für Extraterrestrische Physik (MPE), Thayer School of Engineering, Dartmouth College [Hanover], Institute of Space Science [Bucharest-Măgurele] (ISS), Centre d'étude spatiale des rayonnements (CESR), Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées, EOS Space Science Center [Durham], University of New Hampshire (UNH), Imperial College London, Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)

Subjects
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, lcsh:Geophysics. Cosmic physics, lcsh:QC801-809, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, lcsh:Q, lcsh:Science, lcsh:Physics, lcsh:QC1-999
Abstract

International audience; Since December 2000, the Cluster satellites have been conducting detailed measurements of the magnetospheric boundaries and have confirmed the unambiguous presence of ions of terrestrial origin (e.g. O+ in regions adjacent to the dayside, mid-latitude magnetopause. In the present paper, we focus on the statistical properties of the O+ ion component at energies ranging from 30eV up to 40keV, using three years of ion data at solar maximum from the Cluster Ion Spectrometry (CIS) experiment aboard two Cluster spacecraft. The O+ density decreases on average by a factor of 6, from 0.041 to 7x10-3cm-3 when crossing the magnetopause from the magnetosphere to the magnetosheath, but depends on several parameters, such as the geomagnetic activity or the modified disturbed storm time index (Dst*), and on their location. The O+ density is significantly higher in the dusk-side than in the dawn side region, which is consistent with the view that they originate mainly from the plasma sheet. A remarkable finding is that inward of the magnetopause, O+ is the dominant contributor to the mass density 30% of the time on the dusk-side in comparison to 3% in the dawnside and 4% near noon. On an event basis in the dusk flank of the magnetopause, we point out that O+ ions, when dominating the mass composition, lower the threshold for generating the Kelvin-Helmholtz instability, which may allow plasma exchange between the magnetosheath and the plasma sheet. We also discuss the effect of a substantial O+ ion component when present in a reconnection region.

Published
2005

20. Monitoring magnetosheath-magnetosphere interconnection topology from the aurora

Author

P. E. Sandholt, C. J. Farrugia, EGU, Publication, Department of Physics, Okayama University, EOS Space Science Center [Durham], and University of New Hampshire (UNH)

Subjects
Atmospheric Science, 010504 meteorology & atmospheric sciences, Field line, Equator, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, Magnetosphere, Astrophysics, 01 natural sciences, Magnetosheath, 0103 physical sciences, Earth and Planetary Sciences (miscellaneous), Astrophysics::Solar and Stellar Astrophysics, lcsh:Science, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Physics, Flux tube, [SDU.OCEAN] Sciences of the Universe [physics]/Ocean, Atmosphere, lcsh:QC801-809, Plasma sheet, Geology, Astronomy and Astrophysics, Magnetic reconnection, Geophysics, lcsh:QC1-999, lcsh:Geophysics. Cosmic physics, 13. Climate action, Space and Planetary Science, Physics::Space Physics, [SDU.STU] Sciences of the Universe [physics]/Earth Sciences, Magnetopause, lcsh:Q, lcsh:Physics
Abstract

A strong southward rotation of the IMF (BZ from 5 to -6 nT in ~ 20 s) on 4 January 1995 caused an abrupt reconfiguration of midday aurorae and plasma convection consisting of the following: (1) the red-line aurora associated with magnetosheath plasma transfer at the low-latitude magnetopause appeared at the same time that (2) the green-line aurora from precipitating energetic plasma sheet particles equatorward of the cusp (near the open-closed field line boundary) weakened visibly and shifted equatorward, (3) the high-latitude aurora during the previous northward IMF, which is associated with lobe reconnection, persisted briefly (3 min) and brightened, before it disappeared from the field-of-view, (4) the activation of a strong convection bay (DPY current) at cusp and sub-cusp latitudes when the field turned strongly south, (5) a distinct wave motion of the plasma sheet outer boundary, as inferred from the aurora, which correlates closely with Pc 5 magnetic pulsations. Our interpretation of the dramatic reconfiguration is that reconnection poleward of the cusp coexisted briefly with reconnection at sub-cusp latitudes. The latter provided a magnetic field connection which enabled, on the one hand, magnetosheath particles to enter and cause the red-line cusp aurora, and on the other hand, allowed for magnetospheric energetic particles to escape and weaken the outer plasma sheet source of the green-line emission. The coexistence of the two cusp auroras reflects the time required for one field line topology to replace another, which, under the prevailing high speed wind ( ~ 650 km/s), lasts ~ 3–4 min. The motion of open flux tubes propagating from equator to pole during this transition is traced in the aurora by a poleward moving form. The waves on the outer boundary of the plasma sheet are most likely due to the Kelvin-Helmholtz instability. The study illustrates the ability of local auroral observations to monitor even a global change in magnetospheric magnetic topology.Key words. Magnetospheric Physics (auroral phenomena; magnetopause, cusp, and boundary layers; solar wind-magnethoshere interactions)

Published
2002

21. INTERSTELLAR HYDROGEN FLUXES MEASURED BY IBEX -LO IN 2009: NUMERICAL MODELING AND COMPARISON WITH THE DATA

Author

Dmitry Alexashov, Olga Katushkina, Nathan A. Schwadron, Vladislav Izmodenov, David J. McComas, HELIOS - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Space Research Institute of the Russian Academy of Sciences (IKI), Russian Academy of Sciences [Moscow] (RAS), institute for Problems in Mechanics [Moscow], Lomonosov Moscow State University (MSU), EOS Space Science Center [Durham], University of New Hampshire (UNH), Southwest Research Institute [San Antonio] (SwRI), and The University of Texas at San Antonio (UTSA)

Subjects
010504 meteorology & atmospheric sciences, Hydrogen, FOS: Physical sciences, Numerical modeling, chemistry.chemical_element, Kinetic energy, 7. Clean energy, 01 natural sciences, Bin, 0103 physical sciences, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), 0105 earth and related environmental sciences, Physics, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Astronomy and Astrophysics, Computational physics, Astrophysics - Solar and Stellar Astrophysics, Radiation pressure, chemistry, 13. Climate action, Space and Planetary Science, Physics::Space Physics, Orbit (dynamics), Heliosphere, Energy (signal processing)
Abstract

In this paper, we perform numerical modeling of the interstellar hydrogen fluxes measured by IBEX-Lo during orbit 23 (spring 2009) using a state-of-the-art kinetic model of the interstellar neutral hydrogen distribution in the heliosphere. This model takes into account the temporal and heliolatitudinal variations of the solar parameters as well as non-Maxwellian kinetic properties of the hydrogen distribution due to charge exchange in the heliospheric interface. We found that there is a qualitative difference between the IBEX-Lo data and the modeling results obtained with the three-dimensional, time-dependent model. Namely, the model predicts a larger count rate in energy bin~2 (20-41 eV) than in energy bin~1 (11-21 eV), while the data shows the opposite case. We perform study of the model parameter effects on the IBEX-Lo fluxes and the ratio of fluxes in two energy channels. We shown that the most important parameter, which has a major influence on the ratio of the fluxes in the two energy bins, is the solar radiation pressure. The parameter fitting procedure shows that the best agreement between the model result and the data occurs in the case when the ratio of the solar radiation pressure to the solar gravitation, $\mu_0$, is 1.26$^{+0.06}_{-0.076}$, and the total ionization rate of hydrogen at 1 AU is $\beta_{E,0}=3.7^{+0.39}_{-0.35}\times 10^{-7}$~s$^{-1}$. We have found that the value of $\mu_0$ is much larger than $\mu_0=0.89$, which is the value derived from the integrated solar Lyman-alpha flux data for the period of time studied. We discuss possible reasons for the differences.

Published
2015

22. Observations of concentrated generator regions in the nightside magnetosphere by Cluster/FAST conjunctions

Author

M. Hamrin, O. Marghitu, K. Rönnmark, B. Klecker, M. André, S. Buchert, L. M. Kistler, J. McFadden, H. Rème, A. Vaivads, Department of Physics, Okayama University, Institute of Space Science [Bucharest-Măgurele] (ISS), Max-Planck-Institut für Extraterrestrische Physik (MPE), Swedish Institute of Space Physics [Kiruna] (IRF), EOS Space Science Center [Durham], University of New Hampshire (UNH), Space Sciences Laboratory [Berkeley] (SSL), University of California [Berkeley], University of California-University of California, Centre d'étude spatiale des rayonnements (CESR), Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées, University of California [Berkeley] (UC Berkeley), University of California (UC)-University of California (UC), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)

Subjects
Atmospheric Science, 010504 meteorology & atmospheric sciences, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, Flux, Magnetosphere, Astrophysics, Kinetic energy, 01 natural sciences, Electromagnetic radiation, Fusion, plasma och rymdfysik, Electric field, 0103 physical sciences, Earth and Planetary Sciences (miscellaneous), lcsh:Science, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Physics, lcsh:QC801-809, Plasma sheet, Geology, Astronomy and Astrophysics, Geophysics, Plasma, Fusion, Plasma and Space Physics, lcsh:QC1-999, lcsh:Geophysics. Cosmic physics, 13. Climate action, Space and Planetary Science, Poynting vector, lcsh:Q, lcsh:Physics
Abstract

Here and in the companion paper, Marghitu etal.(2006), we investigate plausible auroral generator regions in the nightside auroral magnetosphere. In this article we use magnetically conjugate data from the Cluster and the FAST satellites during a 3.5-h long event from 19-20September 2001. Cluster is in the Southern Hemisphere close to apogee, where it probes the plasma sheet and lobe at an altitude of about 18 RE. FAST is below the acceleration region at approximately 0.6 RE. Searching for clear signatures of negative power densities, E·JE·JEyJy. The electric field Ey is weakly negative during most of our entire event and we conclude that the CGRs occur when the duskward current Jy grows large and positive. We find that our observations are consistent with a local southward expansion of the plasma sheet and/or rather complicated, 3-D wavy structures propagating over the Cluster satellites. We find that the plasma is working against the magnetic field, and that kinetic energy is being converted into electromagnetic energy. Some of the energy is transported away as Poynting flux.

Published
2006

23. Plasmapheric plumes: CLUSTER, image and simulations

Author

Darrouzet, F., De Keyser, J., Décréau, Pierrette, L. Gallagher, D., Pierrard, V., F. Lemaire, J., Sandel, B. R., Dandouras, I., Matsui, H., Dunlop, M., Cabrera, J., Masson, A., Canu, P., Trotignon, Jean-Gabriel, Rauch, Jean-Louis, André, M., Belgian Institute for Space Aeronomy / Institut d'Aéronomie Spatiale de Belgique (BIRA-IASB), Laboratoire de physique et chimie de l'environnement (LPCE), Université d'Orléans (UO)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), NASA Marshall Space Flight Center (MSFC), Center for Space Radiations [Louvain-la-Neuve] (CSR), Université Catholique de Louvain = Catholic University of Louvain (UCL), Lunar and Planetary Laboratory [Tucson] (LPL), University of Arizona, Centre d'étude spatiale des rayonnements (CESR), Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées, EOS Space Science Center [Durham], University of New Hampshire (UNH), STFC Rutherford Appleton Laboratory (RAL), Science and Technology Facilities Council (STFC), Centre d'étude des environnements terrestre et planétaires (CETP), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), ESA SP-598, Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)

Subjects
[SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Physics::Space Physics
Abstract

International audience; Plasmaspheric plumes have been routinely observed by the CLUSTER and IMAGE missions. CLUSTER provides high time resolution four-point measurements of the plasmasphere. Electron density is derived from the WHISPER sounder supplemented by data from the electric field instrument EFW. The EUV imager onboard IMAGE provides global images of the plasmasphere. We present coordinated observations of one plume event and numerical simulations for its formation based on the interchange instability mechanism. We compare several aspects of the plume motion as determined by different methods: (i) boundary velocity calculated from time delays of plume boundaries observed by WHISPER on all four spacecraft, (ii) ion velocity derived from the ion spectrometer CIS onboard CLUSTER, (iii) drift velocity measured by the electron drift instrument EDI onboard CLUSTER and (iv) global velocity determined from successive EUV images. These different methods consistently indicate that plasmaspheric plumes rotate around the Earth, with their foot fully co-rotating, but with their tip rotating slower and moving farther out.

Published
2005

24. Pulsed flows at the high-altitude cusp poleward boundary, and associated ionospheric convection and particle signatures, during a Cluster - FAST - SuperDARN- Søndrestrøm conjunction under a southwest IMF

Author

Per Even Sandholt, J. A. Wild, Jean-Claude Cerisier, J. D. Kelly, Charlie J. Farrugia, Stanley W. H. Cowley, Eric J. Lund, George K. Parks, C. W. Carlson, André Balogh, J. M. Bosqued, J. A. Sauvaud, Malcolm Dunlop, Eberhard Möbius, C. G. Mouikis, H. Rème, Space Science Center & Department of Physics, University of New Hampshire (UNH), Department of Physics [Oslo], Faculty of Mathematics and Natural Sciences [Oslo], University of Oslo (UiO)-University of Oslo (UiO), Department of Physics and Astronomy [Leicester], University of Leicester, Blackett Laboratory, Imperial College London, STFC Rutherford Appleton Laboratory (RAL), Science and Technology Facilities Council (STFC), Centre d'étude spatiale des rayonnements (CESR), Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées, Space Sciences Laboratory [Berkeley] (SSL), University of California [Berkeley], University of California-University of California, Centre d'étude des environnements terrestre et planétaires (CETP), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), SRI International [Menlo Park] (SRI), Department of Physics [Durham], EOS Space Science Center [Durham], Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Université Fédérale Toulouse Midi-Pyrénées-Météo-France -Institut de Recherche pour le Développement (IRD)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), University of California [Berkeley] (UC Berkeley), and University of California (UC)-University of California (UC)

Subjects
Atmospheric Science, 010504 meteorology & atmospheric sciences, Field line, Magnetosphere, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, 01 natural sciences, Alfvén wave, [PHYS.PHYS.PHYS-PLASM-PH]Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph], 0103 physical sciences, Earth and Planetary Sciences (miscellaneous), lcsh:Science, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Physics, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Flux tube, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], lcsh:QC801-809, Geology, Astronomy and Astrophysics, Geophysics, lcsh:QC1-999, Solar wind, Boundary layer, lcsh:Geophysics. Cosmic physics, Earth's magnetic field, Space and Planetary Science, Physics::Space Physics, lcsh:Q, Ionosphere, lcsh:Physics
Abstract

Particle and magnetic field observations during a magnetic conjunction Cluster 1-FAST-Søndrestrøm within the field of view of SuperDARN radars on 21 January 2001 allow us to draw a detailed, comprehensive and self-consistent picture at three heights of signatures associated with transient reconnection under a steady south-westerly IMF (clock angle ≈130°). Cluster 1 was outbound through the high altitude (~12RE) exterior northern cusp tailward of the bifurcation line (geomagnetic Bx>0) when a solar wind dynamic pressure release shifted the spacecraft into a boundary layer downstream of the cusp. The centerpiece of the investigation is a series of flow bursts observed there by the spacecraft, which were accompanied by strong field perturbations and tailward flow deflections. Analysis shows these to be Alfvén waves. We interpret these flow events as being due to a sequence of reconnected flux tubes, with field-aligned currents in the associated Alfvén waves carrying stresses to the underlying ionosphere, a view strengthened by the other observations. At the magnetic footprint of the region of Cluster flow bursts, FAST observed an ion energy-latitude disperison of the stepped cusp type, with individual cusp ion steps corresponding to individual flow bursts. Simultaneously, the SuperDARN Stokkseyri radar observed very strong poleward-moving radar auroral forms (PMRAFs) which were conjugate to the flow bursts at Cluster. FAST was traversing these PMRAFs when it observed the cusp ion steps. The Søndrestrøm radar observed pulsed ionospheric flows (PIFs) just poleward of the convection reversal boundary. As at Cluster, the flow was eastward (tailward), implying a coherent eastward (tailward) motion of the hypothesized open flux tubes. The joint Søndrestrøm and FAST observations indicate that the open/closed field line boundary was equatorward of the convection reversal boundary by ~2°. The unprecedented accuracy of the conjunction argues strongly for the validity of the interpretation of the various signatures as resulting from transient reconnection. In particular, the cusp ion steps arise on this pass from this origin, in consonance with the original pulsating cusp model. The observations point to the need of extending current ideas on the response of the ionosphere to transient reconnection. Specifically, it argues in favor of re-establishing the high-latitude boundary layer downstream of the cusp as an active site of momentum transfer.

Published
2004

25. Dayside aurora and the role of IMF ?By?/?Bz?: detailed morphology and response to magnetopause reconnection

Author

Sandholt, P. E., Farrugia, C. J., Denig, W. F., EGU, Publication, Department of Physics, Okayama University, EOS Space Science Center [Durham], University of New Hampshire (UNH), AFRL Space Vehicles Directorate, Air Force Research Laboratory (AFRL), and United States Air Force (USAF)-United States Air Force (USAF)

Subjects
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, [SDU.OCEAN] Sciences of the Universe [physics]/Ocean, Atmosphere, [SDU.STU] Sciences of the Universe [physics]/Earth Sciences, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences
Abstract

International audience; We document the detailed spatio-temporal structure of the dayside aurora during intervals of ongoing dayside magnetopause reconnection, primarily during interplanetary magnetic field (IMF) Bz?0 conditions. The present study is based on ground auroral observations in combination with particle precipitation data from a DMSP spacecraft. We describe auroral forms corresponding to the following particle precipitation regimes identified by Newell and Meng (1994): (i) central plasma sheet (CPS), (ii) precipitation void, (iii) dayside boundary plasma sheet (BPS), and (iv) cusp (LLBL/cusp/mantle). Two distinctly different auroral configurations are observed, corresponding to different regimes of the IMF clock angle (?) and the ?By?/?Bz? ratio. Two regimes are defined. In regime (I) ? lies within ? 90?135° and ?By?/?Bz?>1 (By-dominated), while in regime (II) ? is in the range 135°?180° and ?By?/?Bz?Bz-dominated). Within regime (I) the auroral response to reconnection events typically progresses from lower to higher latitudes in stages as indicated below: (A) equatorward boundary intensifications (EBIs): sequential brightenings of closely spaced, fragmented, rayed bands (BPS aurora) within the ?08:00?15:00 MLT sector, each of which are moving noonward/sunward, (B) poleward moving auroral forms (PMAFs): forms expanding westward from the postnoon side (By>0) and later appearing as a poleward expanding form in the convection throat in the ?09:00?12:00 MLT sector, with a fading phase in the regime of mantle precipitation. During strongly southward IMF conditions (regime II), the intense PMAF activity is replaced by a more latitudinally restricted, but longitudinally wide aurora of moderate intensity. The latter auroral state is accompanied by a 2-cell convection pattern which is rather symmetrical about noon. This state is very different from the convection/FAC configuration present during IMF regime (I), with its strong zonal flows (convection current), more intense FAC sheets and PMAF activity in the midday sector. The strong IMF regulation of the dayside BPS aurora, consisting of keV electrons, and its location with respect to the green line auroral gap (precipitation void), indicate that it is an important signature of the reconnection process, located on open boundary layer field lines. The observed longitudinal bifurcation of the auroral brightenings (EBIs) preceding PMAFs is consistent with antiparallel magnetopause reconnection. Key words. Magnetospheric physics (auroral phenomena magnetopause, cusp, and boundary layers: solar windmagnetosphere interactions) ? Ionosphere (particle precipitation)

Published
2004

26. On the altitude dependence of transversely heated O+ distributions in the cusp/cleft

Author

Bouhram, M., Klecker, B., Miyake, W., Rème, H., Sauvaud, J.-A., Malingre, M., Kistler, L., Blagau, A., Max-Planck-Institut für Extraterrestrische Physik (MPE), Communications Research Laboratory (CRL), National Institute of Information and Communications Technology [Tokyo, Japan] (NICT), Centre d'étude spatiale des rayonnements (CESR), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Centre d'étude des environnements terrestre et planétaires (CETP), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), EOS Space Science Center [Durham], University of New Hampshire (UNH), Institute of Space Science [Bucharest-Măgurele] (ISS), Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), and Université Fédérale Toulouse Midi-Pyrénées

Subjects
[PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], [PHYS.PHYS.PHYS-PLASM-PH]Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph], Physics::Space Physics
Abstract

The present paper focuses on the altitude dependence of oxygen ion conics in the dayside cusp/cleft region. Here, combining oxygen data from the Akebono, Interball-2 and Cluster satellites allows, for the first time, one to follow the global development of energetic (up to ~10keV) ion outflow over a continuous and broad altitude range up to about 5.5 Earth radii (RE). According to earlier statistical studies, the results are consistent with a height-integrated energization of ions at altitudes up to 3.5 RE. Higher up, the results inferred from Cluster observations put forward evidence of a saturation of both a transverse energization rate and ion gyroradii. We suggest that such results may be interpreted as finite perpendicular wavelength effects (a few tens of km) in the wave-particle interactions. To substantiate the suggestion, we carry out two-dimensional, Monte Carlo simulations of ion conic production that incorporate such effects and limited residence times due to the finite latitudinal extent of the heating region.Key words. Magnetospheric physics (auroral phenomena) – Space plasma physics (charged particle motion and acceleration; wave-particle interactions)

Published
2004

27. Electric field measurements on Cluster: comparing the double-probe and electron drift techniques

Author

A. I. Eriksson, M. André, B. Klecker, H. Laakso, P.-A. Lindqvist, F. Mozer, G. Paschmann, A. Pedersen, J. Quinn, R. Torbert, K. Torkar, H. Vaith, Swedish Institute of Space Physics [Kiruna] (IRF), Max-Planck-Institut für Extraterrestrische Physik (MPE), ESA Solar System Division, European Space Research and Technology Centre (ESTEC), European Space Agency (ESA)-European Space Agency (ESA), Alfven Laboratory, Royal Institute of Technology [Stockholm] (KTH ), Space Sciences Laboratory [Berkeley] (SSL), University of California [Berkeley], University of California-University of California, International Space Science Institute [Bern] (ISSI), Department of Physics, Okayama University, EOS Space Science Center [Durham], University of New Hampshire (UNH), Space Research Institute of Austrian Academy of Sciences (IWF), Austrian Academy of Sciences (OeAW), and EGU, Publication

Subjects
Atmospheric Science, 010504 meteorology & atmospheric sciences, Population, Magnetosphere, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, Electron, 7. Clean energy, 01 natural sciences, Electric field, 0103 physical sciences, Earth and Planetary Sciences (miscellaneous), education, lcsh:Science, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Physics, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, education.field_of_study, [SDU.OCEAN] Sciences of the Universe [physics]/Ocean, Atmosphere, lcsh:QC801-809, Plasma sheet, Geology, Astronomy and Astrophysics, Plasma, lcsh:QC1-999, Magnetic field, lcsh:Geophysics. Cosmic physics, Polar wind, Space and Planetary Science, [SDU.STU] Sciences of the Universe [physics]/Earth Sciences, lcsh:Q, Atomic physics, lcsh:Physics
Abstract

The four Cluster satellites each carry two instruments designed for measuring the electric field: a double-probe instrument (EFW) and an electron drift instrument (EDI). We compare data from the two instruments in a representative sample of plasma regions. The complementary merits and weaknesses of the two techniques are illustrated. EDI operations are confined to regions of magnetic fields above 30 nT and where wave activity and keV electron fluxes are not too high, while EFW can provide data everywhere, and can go far higher in sampling frequency than EDI. On the other hand, the EDI technique is immune to variations in the low energy plasma, while EFW sometimes detects significant nongeophysical electric fields, particularly in regions with drifting plasma, with ion energy (in eV) below the spacecraft potential (in volts). We show that the polar cap is a particularly intricate region for the double-probe technique, where large nongeophysical fields regularly contaminate EFW measurments of the DC electric field. We present a model explaining this in terms of enhanced cold plasma wake effects appearing when the ion flow energy is higher than the thermal energy but below the spacecraft potential multiplied by the ion charge. We suggest that these conditions, which are typical of the polar wind and occur sporadically in other regions containing a significant low energy ion population, cause a large cold plasma wake behind the spacecraft, resulting in spurious electric fields in EFW data. This interpretation is supported by an analysis of the direction of the spurious electric field, and by showing that use of active potential control alleviates the situation.

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