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1. Generalized Time‐Series Analysis for In Situ Spacecraft Observations: Anomaly Detection and Data Prioritization Using Principal Components Analysis and Unsupervised Clustering

Author

Matthew G. Finley, Miguel Martinez‐Ledesma, William R. Paterson, Matthew R. Argall, David M. Miles, John C. Dorelli, and Eftyhia Zesta

Subjects
anomaly detection, data prioritization, event detection, onboard processing, principal components analysis, unsupervised clustering, Astronomy, QB1-991, Geology, QE1-996.5
Abstract

Abstract In situ spacecraft observations are critical to our study and understanding of the various phenomena that couple mass, momentum, and energy throughout near‐Earth space and beyond. However, on‐orbit telemetry constraints can severely limit the capability of spacecraft to transmit high‐cadence data, and missions are often only able to telemeter a small percentage of their captured data at full rate. This presents a programmatic need to prioritize intervals with the highest probability of enabling the mission's science goals. Larger missions such as the Magnetospheric Multiscale mission (MMS) aim to solve this problem with a Scientist‐In‐The‐Loop (SITL), where a domain expert flags intervals of time with potentially interesting data for high‐cadence data downlink and subsequent study. Although suitable for some missions, the SITL solution is not always feasible, especially for low‐cost missions such as CubeSats and NanoSats. This manuscript presents a generalizable method for the detection of anomalous data points in spacecraft observations, enabling rapid data prioritization without substantial computational overhead or the need for additional infrastructure on the ground. Specifically, Principal Components Analysis and One‐Class Support Vector Machines are used to generate an alternative representation of the data and provide an indication, for each point, of the data's potential for scientific utility. The technique's performance and generalizability is demonstrated through application to intervals of observations, including magnetic field data and plasma moments, from the CASSIOPE e‐POP/Swarm‐Echo and MMS missions.

Published
2024
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3. Wave-particle energy exchange directly observed in a kinetic Alfvén-branch wave

Author

Daniel J. Gershman, Adolfo F-Viñas, John C. Dorelli, Scott A. Boardsen, Levon A. Avanov, Paul M. Bellan, Steven J. Schwartz, Benoit Lavraud, Victoria N. Coffey, Michael O. Chandler, Yoshifumi Saito, William R. Paterson, Stephen A. Fuselier, Robert E. Ergun, Robert J. Strangeway, Christopher T. Russell, Barbara L. Giles, Craig J. Pollock, Roy B. Torbert, and James L. Burch

Subjects
Science
Abstract

Alfvén waves are fundamental plasma modes that provide a mechanism for the transfer of energy between particles and fields. Here the authors confirm experimentally the conservative energy exchange between Alfvén wave fields and plasma particles via high-resolution MMS observations of Earth’s magnetosphere.

Published
2017
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5. Magnetotail reconnection asymmetries in an ion-scale, Earth-like magnetosphere

Author

Christopher M. Bard and John C. Dorelli

Subjects
Atmospheric Science, Space and Planetary Science, QC801-809, Science, Physics, QC1-999, Physics::Space Physics, Geophysics. Cosmic physics, Earth and Planetary Sciences (miscellaneous), Geology, Astronomy and Astrophysics, Astrophysics::Earth and Planetary Astrophysics
Abstract

We use a newly developed global Hall magnetohydrodynamic (MHD) code to investigate how reconnection drives magnetotail asymmetries in small, ion-scale magnetospheres. Here, we consider a magnetosphere with a similar aspect ratio to Earth but with the ion inertial length (δi) artificially inflated by a factor of 70: δi is set to the length of the planetary radius. This results in a magnetotail width on the order of 30 δi, slightly smaller than Mercury's tail and much smaller than Earth's with respect to δi. At this small size, we find that the Hall effect has significant impact on the global flow pattern, changing from a symmetric, Dungey-like convection under resistive MHD to an asymmetric pattern similar to that found in previous Hall MHD simulations of Ganymede's subsonic magnetosphere as well as other simulations of Mercury's using multi-fluid or embedded kinetic physics. We demonstrate that the Hall effect is sufficient to induce a dawnward asymmetry in observed dipolarization front locations and find quasi-periodic global-scale dipolarizations under steady, southward solar wind conditions. On average, we find a thinner current sheet dawnward; however, the measured thickness oscillates with the dipolarization cycle. During the flux-pileup stage, the dawnward current sheet can be thicker than the duskward sheet. This could be an explanation for recent observations that suggest Mercury's current sheet is actually thicker on the duskside: a sampling bias due to a longer lasting “thick” state in the sheet.

Published
2021

6. Structures in the terms of the Vlasov equation observed at Earth’s magnetopause

Author

Shan Wang, C. Schiff, Richard E. Denton, D. Da Silva, A. F. Viñas, Roy B. Torbert, Naoki Bessho, J. R. Shuster, John C. Dorelli, Paul Cassak, Levon A. Avanov, Steven J. Schwartz, W. R. Paterson, D. J. Gershman, L. J. Chen, Jonathan Ng, Vadim M. Uritsky, and Barbara L. Giles

Subjects
Physics, Physics::Plasma Physics, Phase space, Physics::Space Physics, Vlasov equation, General Physics and Astronomy, Magnetopause, Magnetic reconnection, Astrophysical plasma, Plasma, Electron, Kinetic energy, Computational physics
Abstract

The Vlasov equation describes collisionless plasmas in the continuum limit and applies to many fundamental plasma energization phenomena. Because this equation governs the evolution of plasma in six-dimensional phase space, studies of its structure have mostly been limited to numerical or analytical methods. Here terms of the Vlasov equation are determined from observations of electron phase-space density gradients measured by the four Magnetospheric Multiscale spacecraft in the vicinity of magnetic reconnection at Earth’s magnetopause. We identify which electrons in velocity space substantially support the electron pressure divergence within electron-scale current layers. Furthermore, we isolate and characterize the effects of density, velocity and temperature gradients on the velocity-space structure and dynamics of these electrons. Unipolar, bipolar and ring structures in the electron phase-space density gradients are compared to a simplified Maxwellian model and correspond to localized gradients in density, velocity and temperature, respectively. These structures have implications for the ability of collisionless plasmas to maintain kinetic Vlasov equilibrium. The results provide a kinetic perspective relevant to how the electron pressure divergence may develop to violate the electron frozen-in condition and sustain electron-scale energy conversion processes, such as the reconnection electric field, in collisionless space plasma environments. Insights into the structure of the Vlasov equation that governs the evolution of collisionless plasmas from observations have been limited. Now the spatial gradient term for electrons is analysed with recent data from the MMS mission.

Published
2021

7. Ion Kinetics in a Hot Flow Anomaly: MMS Observations

Author

Steven J Schwartz, Levon Avanov, Drew Turner, Hui Zhang, Imogen Gingell, Jonathan P Eastwood, Daniel J Gershman, Andreas Johlander, Christopher T Russell, James L Burch, John C Dorelli, Stefan Eriksson, Robert E Ergun, Stephen A Fuselier, Barbara L Giles, Katherine A Goodrich, Yuri V Khotyaintsev, Benoit Lavraud, Per‐Arne Lindqvist, Mitsuo Oka, Tai‐Duc Phan, Robert J Strangeway, Karlheinz J Trattner, Roy B Torbert, Andris Vaivads, Hanying Wei, and Frederick Wilder

Published
2018
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10. Recommendations to Advance Space Trusted Autonomy

Author

Erica Rodgers, C. Bard, Gregory Benjamin, Alejandro Pensado, Steven Lewis, Matthew A. Stafford, Kara A. Latorella, Christopher A. Jones, Anthony Patrick, John C. Dorelli, and Jason Hay

Subjects
Computer science, media_common.quotation_subject, Space (commercial competition), Computer security, computer.software_genre, computer, Autonomy, media_common
Published
2021

12. Statistical Survey of Collisionless Dissipation in the Terrestrial Magnetosheath

Author

Craig J. Pollock, Thomas E. Moore, Rohit Chhiber, Roy Torbert, Yanwen Wang, James L. Burch, Barbara L. Giles, Yan Yang, William H. Matthaeus, Alexandros Chasapis, Christopher T. Russell, John C. Dorelli, Daniel J. Gershman, Frederick Wilder, Riddhi Bandyopadhyay, and Robert J. Strangeway

Subjects
Physics, Solar wind, Geophysics, Magnetosheath, Similarity (network science), Space and Planetary Science, Dissipation, Statistical survey
Published
2021

13. Magnetotail Reconnection Asymmetries in a Small, Earth-Like Magnetosphere

Author

John C. Dorelli and C. Bard

Subjects
Physics, Convection, media_common.quotation_subject, Magnetosphere, Radius, Asymmetry, Computational physics, Solar wind, Current sheet, Hall effect, Physics::Space Physics, Astrophysics::Earth and Planetary Astrophysics, Magnetohydrodynamics, media_common
Abstract

We use a newly developed global Hall MHD code to investigate how reconnection drives magnetotail asymmetries in small magnetospheres. Here, we consider a scaled-down, Earth-like magnetosphere where the ion inertial length (δi) is artificially inflated to one planetary radius (the real Earth's δi ≈ 1/15–1/20 RE in the magnetotail). This results in a magnetotail width on the order of 30 δi, slightly smaller than Mercury's tail and much smaller than Earth's. At this small size, we find that the Hall effect has significant impact on the global flow pattern, changing from a symmetric, Dungey-like convection under resistive MHD to an asymmetric pattern similar to that found in previous Hall MHD simulations of Ganymede's subsonic magnetosphere as well as other simulations of Mercury's using multi-fluid or embedded kinetic physics. We demonstrate that the Hall effect is sufficient to induce a dawnward asymmetry in observed dipolarization front locations and find quasi-periodic global scale dipolarizations under steady, southward solar wind conditions. On average, we find a thinner current sheet dawnward; however, the measured thickness oscillates with the dipolarization cycle. During the flux-pileup stage, the dawnward current sheet can be thicker than the duskward sheet. This could be an explanation for recent observations that suggest Mercury's current sheet is actually thicker on the duskside: a sampling bias due to a longer-lasting "thick" state in the sheet.

Published
2020

14. 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

15. Magnetic Reconnection Inside a Flux Transfer Event‐Like Structure in Magnetopause Kelvin‐Helmholtz Waves

Author

Thomas E. Moore, W. R. Paterson, N. Fargette, Craig J. Pollock, Emmanuel Penou, John C. Dorelli, Tai Phan, Christian Jacquey, Levon A. Avanov, Benoit Lavraud, A. C. Rager, Barbara L. Giles, Vincent Génot, Yoshitaka Saito, James L. Burch, K. Malakit, Claire Foullon, S. Fadanelli, K. J. Hwang, Y Vernisse, Hiroshi Hasegawa, David Ruffolo, C. Schiff, Daniel J. Gershman, Sergio Toledo-Redondo, M. Oieroset, R. Kieokaew, J. A. Sauvaud, 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), University of Warwick [Coventry], Space Sciences Laboratory [Berkeley] (SSL), University of California [Berkeley] (UC Berkeley), University of California (UC)-University of California (UC), Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency [Sagamihara] (JAXA), NASA Goddard Space Flight Center (GSFC), Space Science Division [San Antonio], Southwest Research Institute [San Antonio] (SwRI), NASA Headquarters, Catholic University of America, Hokkaido University [Sapporo, Japan], Centre d'Immunologie de Marseille - Luminy (CIML), Aix Marseille Université (AMU)-Institut National de la Santé et de la Recherche Médicale (INSERM)-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-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), University of California [Berkeley], University of California-University of California, and Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU)

Subjects
Physics, 010504 meteorology & atmospheric sciences, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Magnetic reconnection, Plasma, 01 natural sciences, Computational physics, symbols.namesake, Solar wind, Geophysics, Physics::Plasma Physics, Space and Planetary Science, Helmholtz free energy, Physics::Space Physics, symbols, Astrophysics::Solar and Stellar Astrophysics, Magnetopause, Flux transfer event, Physics::Atmospheric and Oceanic Physics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences
Abstract

Magnetopause Kelvin-Helmholtz (KH) waves are believed to mediate solar wind plasma transport via small-scale mechanisms. Vortex-induced reconnection (VIR) was predicted in simulations and recently ...

Published
2020

16. Latitudinal Dependence of the Kelvin‐Helmholtz Instability and Beta Dependence of Vortex‐Induced High‐Guide Field Magnetic Reconnection

Author

Tai Phan, Takuma Nakamura, Daniel J. Gershman, Vincent Génot, Yoshitaka Saito, S. Toledo-Redondo, Hiroshi Hasegawa, Matteo Faganello, Y. Vernisse, M. Sisti, E. Penou, Francesco Califano, C. Jacquey, Charlie J. Farrugia, Thomas E. Moore, James L. Burch, Masha Kuznetsova, Benoit Lavraud, Jérémy Dargent, W. R. Paterson, S. Fadanelli, Craig J. Pollock, John C. Dorelli, J.‐A. Sauvaud, Barbara L. Giles, I. Kacem, Christopher T. Russell, Robert E. Ergun, R. Kieokaew, Stefan Eriksson, Levon A. Avanov, 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), Physique des interactions ioniques et moléculaires (PIIM), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Dipartimento di Fisica, University of Pisa - Università di Pisa, Università degli Studi di Milano-Bicocca = University of Milano-Bicocca (UNIMIB), University of Colorado [Boulder], NASA Goddard Space Flight Center (GSFC), NASA Headquarters, Space Science Division [San Antonio], Southwest Research Institute [San Antonio] (SwRI), 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), Laboratory for Atmospheric and Space Physics [Boulder] (LASP), University of New Hampshire (UNH), Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency [Sagamihara] (JAXA), National Institute for Environmental Studies (NIES), Space Sciences Laboratory [Berkeley] (SSL), University of California [Berkeley] (UC Berkeley), University of California (UC)-University of California (UC), Department of Earth, Planetary and Space Sciences [Los Angeles] (EPSS), University of California [Los Angeles] (UCLA), 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), Università degli Studi di Milano-Bicocca [Milano] (UNIMIB), University of California [Berkeley], University of California-University of California, Centre National de la Recherche Scientifique (CNRS)-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS), Dip. di Fisica dell' Universit ádi Milano-Bicocca I-20126 - Italy, Dipartimento di Fisica 'E Fermi' & CNISM, PSL Research University (PSL)-Sorbonne Université (SU)-Observatoire de Paris, PSL Research University (PSL)-École polytechnique (X)-Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Universités-Université Paris-Saclay, Laboratoire de Parasitologie-Mycologie, Assistance publique - Hôpitaux de Paris (AP-HP) (APHP)-Hôpital Henri Mondor-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12), Centre de physique moléculaire optique et hertzienne (CPMOH), Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1, and Hokkaido University [Sapporo, Japan]

Subjects
010504 meteorology & atmospheric sciences, Field (physics), [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], 01 natural sciences, 010305 fluids & plasmas, Current sheet, space physics, 0103 physical sciences, ComputingMilieux_MISCELLANEOUS, Pressure gradient, 0105 earth and related environmental sciences, Physics, Kelvin-Helmholtz instability, Magnetic reconnection, Space physics, [PHYS.PHYS.PHYS-SPACE-PH]Physics [physics]/Physics [physics]/Space Physics [physics.space-ph], Computational physics, Vortex, Geophysics, 13. Climate action, Space and Planetary Science, magnetic reconnection, Physics::Space Physics, Diamagnetism, Magnetopause, Earth’s magnetosphere
Abstract

International audience; We investigate both large‐ and small‐scale properties of a Kelvin‐Helmholtz (KH) event at the dusk flank magnetopause using Magnetospheric Multiscale observations on 8 September 2015. We first use two types of 3‐D simulations (global and local) to demonstrate that Magnetospheric Multiscale is close to the most KH unstable region, and so the occurrence of vortex‐induced reconnection may be expected. Because they produce low‐shear current sheets, KH vortices constitute a perfect laboratory to investigate magnetic reconnection with large guide field and low asymmetry. Recent works suggest that magnetic reconnection may be suppressed when a current sheet combines large guide field and pressure gradient (which induces a diamagnetic drift). We thus perform a statistical analysis of high‐resolution data for the 69 KH‐induced low‐shear magnetic reconnection events observed on that day. We find that the suppression mechanism is not at work for most of the observed reconnecting current sheets, as predicted, but we also find that almost all nonreconnecting current sheets should be reconnecting according to this model. This confirms the fact that the model provides a necessary but not sufficient condition for reconnection to occur. Finally, based on the same data set, we study the latitudinal distribution of these magnetic reconnection events combined with global magnetospheric modeling. We find that reconnection associated with KH vortices occurs over a significant range of latitudes at the flank magnetopause. It is not confined to the plane where the growth rate is maximum, in agreement with recent 3‐D simulations.

Published
2020

17. Magnetic Reconnection Inside a Flux Rope Induced by Kelvin-Helmholtz Vortices

Author

Robert J. Strangeway, Y. Y. Liu, Hiroshi Hasegawa, Robert E. Ergun, Quanqi Shi, John C. Dorelli, Daniel B. Graham, C. P. Escoubet, Eunjin Choi, Xuanye Ma, Takuma Nakamura, Roy B. Torbert, D. J. Gershman, Barbara L. Giles, Yuri V. Khotyaintsev, Zulin Wang, Christopher T. Russell, L. A. Avanov, David G. Sibeck, C. J. Pollock, Robert Fear, Huimin Fu, W. R. Paterson, Kyunghwan Dokgo, K. J. Hwang, and James L. Burch

Subjects
Kelvin‐Helmholtz wave, Reconnection, 010504 meteorology & atmospheric sciences, Astrophysics::High Energy Astrophysical Phenomena, Flux, Electron, 01 natural sciences, Atmospheric Sciences, Magnetopause and Boundary Layers, Impact crater, Astronomi, astrofysik och kosmologi, Kelvin‐Helmholtz vortex, MHD waves and instabilities, Trailing edge, Astronomy, Astrophysics and Cosmology, Astrophysics::Solar and Stellar Astrophysics, Magnetospheric Physics, Magnetic Reconnection, Research Articles, 0105 earth and related environmental sciences, Flux rope, Physics, Solar Physics, Astrophysics, and Astronomy, MHD waves and turbulence, Magnetospheric Configuration and Dynamics, Magnetic reconnection, Mechanics, Interlinked flux tubes, Plasma and MHD instabilities, Vortex, Interplanetary Physics, Geophysics, Magnetopause, Space and Planetary Science, Physics::Space Physics, Magnetotail Boundary Layers, Space Plasma Physics, Planetary Sciences: Comets and Small Bodies, Astronomical and Space Sciences, Research Article, Rope
Abstract

On 5 May 2017, MMS observed a crater‐type flux rope on the dawnside tailward magnetopause with fluctuations. The boundary‐normal analysis shows that the fluctuations can be attributed to nonlinear Kelvin‐Helmholtz (KH) waves. Reconnection signatures such as flow reversals and Joule dissipation were identified at the leading and trailing edges of the flux rope. In particular, strong northward electron jets observed at the trailing edge indicated midlatitude reconnection associated with the 3‐D structure of the KH vortex. The scale size of the flux rope, together with reconnection signatures, strongly supports the interpretation that the flux rope was generated locally by KH vortex‐induced reconnection. The center of the flux rope also displayed signatures of guide‐field reconnection (out‐of‐plane electron jets, parallel electron heating, and Joule dissipation). These signatures indicate that an interface between two interlinked flux tubes was undergoing interaction, causing a local magnetic depression, resulting in an M‐shaped crater flux rope, as supported by reconstruction., Key Points MMS observed a magnetic flux rope formed on the boundary of a nonlinear Kelvin‐Helmholtz (KH) waveBoth in‐plane and midlatitude reconnection associated with the 3‐D structure of the KH vortex‐inducedflux rope were identifiedA current sheet at the flux rope center supported by reconstruction indicates two flux tubes interlinked to form a crater‐type flux rope

Published
2020

18. Neural Network Repair of Lossy Compression Artifacts in the September 2015 to March 2016 Duration of the MMS/FPI Data Set

Author

John C. Dorelli, D. J. Gershman, Barbara L. Giles, A. C. Barrie, W. R. Patterson, Scot R. Elkington, and D. Da Silva

Subjects
Compression artifact, 010504 meteorology & atmospheric sciences, Neural Networks, Computer science, Image Processing, Image processing, Basis function, Technical Reports: Methods, Data_CODINGANDINFORMATIONTHEORY, Magnetosphere: Outer, Lossy compression, 01 natural sciences, Magnetopause and Boundary Layers, Compression (functional analysis), Magnetospheric Physics, Magnetic Reconnection, 0105 earth and related environmental sciences, Lossless compression, Solar Physics, Astrophysics, and Astronomy, Frame (networking), Mathematical and Numerical Techniques, Magnetosheath, Data set, Geophysics, Space and Planetary Science, Magnetosphere, Space Plasma Physics, Computational Geophysics, Algorithm, Mathematical Geophysics
Abstract

During the September 2015 to March 2016 duration (sometimes referred to as Phase 1A) of the Magnetospheric Multiscale Mission, the Dual Electron Spectrometers (DES) were configured to generously utilize lossy compression. While this maximized the number of velocity distribution functions downlinked, it came at the expense of lost information content for a fraction of the frames. Following this period of lossy compression, the DES was reconfigured in a way that allowed for 95% of the frames to arrive to the ground without loss. Using this high‐quality set of frames from on‐orbit observations, we compressed and decompressed the frames on the ground to create a side‐by‐side record of the compression effect. This record was used to drive an optimization method that (a) derived basis functions capable of approximating the lossless sample space and with nonnegative coefficients and (b) fitted a function which maps the lossy frames to basis weights that recreate the frame without compression artifacts. This method is introduced and evaluated in this paper. Data users should expect a higher level of confidence in the absolute scale of density/temperature measurements and notice less sinusoidal bias in the velocity X and Y components (GSE), Key Points 57% of the burst resolution frames in the September 2015 to March 2016 duration of the MMS mission were affected by some form of lossy compression errorThis data can be corrected by optimizing a model with side‐by‐side examples of the before/after compression effectData users should expect a higher level of confidence in the absolute scale of density/temperature measurements and notice less sinusoidal bias in the velocity X and Y components (GSE)

Published
2020

19. On the Ubiquity of Magnetic Reconnection Inside Flux Transfer Event‐Like Structures at the Earth's Magnetopause

Author

Michael O. Chandler, Elena Grigorenko, S. M. Petrinec, Hiroshi Hasegawa, Charlie J. Farrugia, Victoria N. Coffey, W. R. Paterson, C. Schiff, John C. Dorelli, Thomas E. Moore, Marit Øieroset, S. Fadanelli, K. J. Trattner, Sergio Toledo-Redondo, Jonathan Eastwood, S. A. Fuselier, T. D. Phan, C. J. Pollock, J. A. Sauvaud, Benoit Lavraud, Yoshitaka Saito, Q. Lenouvel, C. Jacquey, Philippe Garnier, James L. Burch, D. J. Gershman, R. Kieokaew, N. Fargette, D. L. A. Avanov, S. E. Smith, Vincent Génot, Emmanuel Penou, Barbara L. Giles, 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), Space Sciences Laboratory [Berkeley] (SSL), University of California [Berkeley], University of California-University of California, Centre de physique moléculaire optique et hertzienne (CPMOH), Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1, Space Science Division [San Antonio], Southwest Research Institute [San Antonio] (SwRI), Lockheed Martin Advanced Technology Center (ATC), Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency [Sagamihara] (JAXA), Laboratoire de microbiologie et génétique moléculaires (LMGM), Centre de Biologie Intégrative (CBI), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), NASA Goddard Space Flight Center (GSFC), 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), NASA Headquarters, Space Research Institute of the Russian Academy of Sciences (IKI), Russian Academy of Sciences [Moscow] (RAS), Hokkaido University [Sapporo, Japan], Centre d'Immunologie de Marseille - Luminy (CIML), Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU), Joint Global Change Research Institute, Pacific Northwest National Laboratory (PNNL)-University of Maryland [College Park], University of Maryland System-University of Maryland System, 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), University of California (UC)-University of California (UC), Université Sciences et Technologies - Bordeaux 1 (UB)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de microbiologie et génétique moléculaires - UMR5100 (LMGM), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS), Aix Marseille Université (AMU)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-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 Sciences et Technologies - Bordeaux 1-Centre National de la Recherche Scientifique (CNRS), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), and Génot, Vincent

Subjects
Physics, 010504 meteorology & atmospheric sciences, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], [SDU.ASTR.EP] Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Magnetic reconnection, Geophysics, 01 natural sciences, Physics::Space Physics, 0103 physical sciences, Meteorology & Atmospheric Sciences, General Earth and Planetary Sciences, Magnetopause, Flux transfer event, 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, Earth (classical element), 0105 earth and related environmental sciences
Abstract

Flux transfer events (FTEs) are transient phenomena frequently observed at the Earth's magnetopause. Their usual interpretation is a flux rope moving away from the reconnection region. However, the Magnetospheric Multiscale Mission revealed that magnetic reconnection sometimes occurs inside these structures, questioning their flux rope configuration. Here we investigate 229 FTE‐type structures and find reconnection signatures inside 19% of them. We analyze their large‐scale magnetic topology using electron heat flux and find that it is significantly different across the FTE reconnecting current sheets, demonstrating that they are constituted of two magnetically disconnected structures. We also find that the interplanetary magnetic field (IMF) associated with reconnecting FTEs presents a strong By component. We discuss several formation mechanisms to explain these observations. In particular, the maximum magnetic shear model predicts that for large IMF By, two spatially distinct X lines coexist at the magnetopause. They can generate separate magnetic flux tubes that may become interlaced.

Published
2020

20. On the deviation from Maxwellian of the ion velocity distribution functions in the turbulent magnetosheath

Author

Ferdinand Plaschke, Rumi Nakamura, John C. Dorelli, Yasuhito Narita, O. Le Contel, Levon A. Avanov, David Fischer, Silvia Perri, Christopher Russell, Barbara L. Giles, Werner Magnes, Robert J. Strangeway, Craig Pollock, William R. Paterson, Luca Sorriso-Valvo, Denise Perrone, D. J. Gershman, Yuri V. Khotyaintsev, Wolfgang Baumjohann, Francesco Valentini, Yoshifumi Saito, Emiliya Yordanova, and Benoit Lavraud

Subjects
Physics, astrophysical plasmas, 010504 meteorology & atmospheric sciences, Plasma parameters, Thermodynamic equilibrium, FOS: Physical sciences, Plasma, Vorticity, Condensed Matter Physics, 01 natural sciences, Space Physics (physics.space-ph), plasma waves, Ion, Computational physics, Magnetosheath, Distribution function, Physics - Space Physics, Astrophysics - Solar and Stellar Astrophysics, Physics::Plasma Physics, Physics::Space Physics, 0103 physical sciences, Magnetopause, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), 0105 earth and related environmental sciences
Abstract

The deviation from thermodynamic equilibrium of the ion velocity distribution functions (VDFs), as measured by the Magnetospheric Multiscale (MMS) mission in the Earth’s turbulent magnetosheath, is quantitatively investigated. Making use of the unprecedented high-resolution MMS ion data, and together with Vlasov–Maxwell simulations, this analysis aims at investigating the relationship between deviation from Maxwellian equilibrium and typical plasma parameters. Correlations of the non-Maxwellian features with plasma quantities such as electric fields, ion temperature, current density and ion vorticity are found to be similar in magnetosheath data and numerical experiments, with a poor correlation between distortions of ion VDFs and current density, evidence that questions the occurrence of VDF departure from Maxwellian at the current density peaks. Moreover, strong correlation has been observed with the magnitude of the electric field in the turbulent magnetosheath, while a certain degree of correlation has been found in the numerical simulations and during a magnetopause crossing by MMS. This work could help shed light on the influence of electrostatic waves on the distortion of the ion VDFs in space turbulent plasmas.

Published
2020

21. Electron Bernstein waves driven by electron crescents near the electron diffusion region

Author

Christopher T. Russell, John C. Dorelli, Ferdinand Plaschke, James L. Burch, Chi Wang, Wenya Li, O. Le Contel, Yuri V. Khotyaintsev, Robert E. Ergun, Kaijun Liu, Andris Vaivads, K. Fujimoto, Mats André, Roy B. Torbert, Daniel J. Gershman, Sergio Toledo-Redondo, Binbin Tang, Kyungguk Min, Benoit Lavraud, Daniel B. Graham, P. A. Lindqvist, Werner Magnes, Cecilia Norgren, A. C. Rager, Barbara L. Giles, National Space Science Center [Beijing] (NSSC), Chinese Academy of Sciences [Beijing] (CAS), Swedish Institute of Space Physics [Uppsala] (IRF), Royal Institute of Technology [Stockholm] (KTH ), Chungnam National University (CNU), Southern University of Science and Technology [Shenzhen] (SUSTech), Beihang University (BUAA), Department of Physics and Technology [Bergen] (UiB), University of Bergen (UiB), 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), Laboratory for Atmospheric and Space Physics [Boulder] (LASP), University of Colorado [Boulder], University of New Hampshire (UNH), Catholic University of America, NASA Goddard Space Flight Center (GSFC), Space Research Institute of Austrian Academy of Sciences (IWF), Austrian Academy of Sciences (OeAW), 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), Department of Earth, Planetary and Space Sciences [Los Angeles] (EPSS), University of California [Los Angeles] (UCLA), University of California-University of California, Southwest Research Institute [San Antonio] (SwRI), Southern University of Science and Technology (SUSTech), 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), and University of California (UC)-University of California (UC)

Subjects
010504 meteorology & atmospheric sciences, Gyroradius, Science, General Physics and Astronomy, Electron, 01 natural sciences, 7. Clean energy, General Biochemistry, Genetics and Molecular Biology, Article, Fusion, plasma och rymdfysik, Space physics, Physics::Plasma Physics, 0103 physical sciences, Diffusion (business), lcsh:Science, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Physics, Multidisciplinary, Magnetic reconnection, General Chemistry, Plasma, Fusion, Plasma and Space Physics, Computational physics, Amplitude, Thermalisation, Magnetospheric physics, Physics::Space Physics, Magnetopause, lcsh:Q, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

The Magnetospheric Multiscale (MMS) spacecraft encounter an electron diffusion region (EDR) of asymmetric magnetic reconnection at Earth’s magnetopause. The EDR is characterized by agyrotropic electron velocity distributions on both sides of the neutral line. Various types of plasma waves are produced by the magnetic reconnection in and near the EDR. Here we report large-amplitude electron Bernstein waves (EBWs) at the electron-scale boundary of the Hall current reversal. The finite gyroradius effect of the outflow electrons generates the crescent-shaped agyrotropic electron distributions, which drive the EBWs. The EBWs propagate toward the central EDR. The amplitude of the EBWs is sufficiently large to thermalize and diffuse electrons around the EDR. The EBWs contribute to the cross-field diffusion of the electron-scale boundary of the Hall current reversal near the EDR., Various types of plasma waves are generated around electron diffusion regions (EDRs). Here the authors show electron Bernstein waves (EBWs), at the electron-scale boundary of the Hall current reversal near EDR, are sufficiently strong to diffuse electrons and modify electron pressure tensor.

Published
2020

22. MMS observations of intense whistler waves within Earth's supercritical bow shock: Source mechanism and impact on shock structure and plasma transport

Author

Laurent Muschietti, P.-E. Lindqvist, John C. Dorelli, O. Le Contel, A. J. Hull, Space Sciences Laboratory [Berkeley] (SSL), University of California [Berkeley], University of California-University of California, HELIOS - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS), 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), NASA Goddard Space Flight Center (GSFC), and Royal Institute of Technology [Stockholm] (KTH )

Subjects
Physics, [PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph], 010504 meteorology & atmospheric sciences, Whistler, Shock (fluid dynamics), Wave packet, Plasma, Electron, 7. Clean energy, 01 natural sciences, Electromagnetic radiation, Computational physics, Wavelength, Geophysics, Space and Planetary Science, [PHYS.PHYS.PHYS-PLASM-PH]Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph], Physics::Space Physics, Bow shock (aerodynamics), 0105 earth and related environmental sciences
Abstract

International audience; The properties of whistler waves near lower‐hybrid frequencies within Earth's quasiperpendicular bow shock are examined using data from the Magnetospheric Multiscale (MMS) mission. These waves appear as right‐hand polarized wave packets propagating upstream obliquely to the magnetic field and shock normal with phase speeds from a few hundred up to 1600 km/s. The wavelengths are near the ion inertial length scale (λ~0.3‐1.3 λi). Detailed analysis finds characteristics consistent with the modified two‐stream instability mechanism driven by the reflected ion and electron drift. Correlations between wave and electron anisotropy variations reveal that the whistlers are affecting electron dynamics and thus their perpendicular and parallel temperatures. The electron signatures are explainable via the interaction of magnetized electrons in the whistler induced non‐monotonic magnetic fields. These waves have intense magnetic fields (δB/Bo~0.1‐1.) and carry sizable currents that are a significant fraction of the thermal current (|J/Jvte|~0.1‐0.5). The whistler induced currents and the electron anisotropies are sufficiently large to respectively excite high‐frequency (HF) electrostatic (> 100 Hz) and HF whistler waves (f~0.1‐0.5 fce). Energy dissipation J•E from whistlers at 30 Hz and below range from a few thousandths to few hundredths of μW/m3. Comparisons reveal that plasma energy is converted to wave energy in the foot, whereas wave energy gets dissipated into the plasma in the ramp, where irreversible heating occurs. These observed features are indicative of an intricate coupling between small‐scale interaction processes and larger‐scale structure transpiring within the layer. Such a characterization is only made possible now with the MMS high‐time‐resolution measurements.

Published
2020

23. Physically Accurate Large Dynamic Range Pseudo Moments for the MMS Fast Plasma Investigation

Author

John C. Dorelli, A. C. Rager, Barbara L. Giles, William R. Paterson, Zoltan Sternovsky, A. C. Barrie, D. Da Silva, Scot R. Elkington, and D. J. Gershman

Subjects
Physics, 010504 meteorology & atmospheric sciences, Artificial neural network, 0103 physical sciences, Large dynamic range, General Earth and Planetary Sciences, Plasma, Environmental Science (miscellaneous), 010303 astronomy & astrophysics, 01 natural sciences, 0105 earth and related environmental sciences, Computational physics
Published
2018

24. New Results FromGalileo's First Flyby of Ganymede: Reconnection-Driven Flows at the Low-Latitude Magnetopause Boundary, Crossing the Cusp, and Icy Ionospheric Escape

Author

William R. Paterson, Glyn Collinson, C. Bard, John C. Dorelli, Menelaos Sarantos, Alex Glocer, and Robert M. Wilson

Subjects
Physics, 010504 meteorology & atmospheric sciences, Plasma sheet, Magnetosphere, Astronomy, Plasma, 01 natural sciences, Physics::Geophysics, Jupiter, Boundary layer, Current sheet, Geophysics, Physics::Space Physics, 0103 physical sciences, General Earth and Planetary Sciences, Magnetopause, Astrophysics::Earth and Planetary Astrophysics, Ionosphere, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences
Abstract

On 27 June 1996, the NASA Galileo spacecraft made humanity’s first flyby of Jupiter’s largest moon, Ganymede, discovering that it is the only moon known to possess an internally generated magnetic field. Resurrecting the original Galileo Plasma Subsystem (PLS) data analysis software, we processed the raw PLS data from G01 and for the first time present the properties of plasmas encountered. Entry into the magnetosphere of Ganymede occurred near the confluence of the magnetopause and plasma sheet. Reconnection-driven plasma flows were observed (consistent with an Earth-like Dungey cycle), which may be a result of reconnection in the plasma sheet, magnetopause, or might be Ganymede’s equivalent of a Low-Latitude Boundary Layer. Dropouts in plasma density combined with velocity perturbations afterward suggest that Galileo briefly crossed the cusps into closed magnetic field lines. Galileo then crossed the cusps, where field-aligned precipitating ions were observed flowing down into the surface, at a location consistent with observations by the Hubble Space Telescope. The density of plasma outflowing from Ganymede jumped an order of magnitude around closest approach over the north polar cap. The abrupt increase may be a result of crossing the cusp or may represent an altitude-dependent boundary such as an ionopause. More diffuse, warmer field-aligned outflows were observed in the lobes. Fluxes of particles near the moon on the nightside were significantly lower than on the dayside, possibly resulting from a diurnal cycle of the ionosphere and/or neutral atmosphere.

Published
2018

25. Plasma Density Estimates From Spacecraft Potential Using MMS Observations in the Dayside Magnetosphere

Author

Wolfgang Baumjohann, Per-Arne Lindqvist, Klaus Torkar, Rumi Nakamura, Yuri Khotyaintsev, John C. Dorelli, James L. Burch, Maria Andriopoulou, Simon Wellenzohn, and Roy B. Torbert

Subjects
Physics, 010504 meteorology & atmospheric sciences, Spacecraft, business.industry, Magnetosphere, 01 natural sciences, Computational physics, Geophysics, Space and Planetary Science, Physics::Space Physics, 0103 physical sciences, Astrophysics::Earth and Planetary Astrophysics, business, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Plasma density
Abstract

Using spacecraft potential observations with and without active spacecraft potential control (on/off) from the Magnetospheric Multiscale (MMS) mission, we estimate the average photoelectron emissio ...

Published
2018

26. Localized Oscillatory Energy Conversion in Magnetopause Reconnection

Author

K. J. Hwang, Daniel B. Graham, Michael Shay, David Newman, Shan Wang, M. Swisdak, Michael Hesse, John C. Dorelli, James Webster, C. J. Pollock, James Drake, James L. Burch, Robert Allen, Robert J. Strangeway, Kevin Genestreti, Richard E. Denton, Robert E. Ergun, D. J. Gershman, Roy B. Torbert, Paul Cassak, Per-Arne Lindqvist, A. C. Rager, O. Le Contel, Barbara L. Giles, Frederick Wilder, Christopher T. Russell, L. J. Chen, T. D. Phan, L. Price, NASA Goddard Space Flight Center (GSFC), 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), University of Maryland [College Park], University of Maryland System, Alfven Laboratory, and Royal Institute of Technology [Stockholm] (KTH )

Subjects
Physics, 010504 meteorology & atmospheric sciences, Astrophysics::High Energy Astrophysical Phenomena, Astrophysics::Instrumentation and Methods for Astrophysics, Boundary (topology), Magnetosphere, Magnetic reconnection, Geophysics, 01 natural sciences, 7. Clean energy, Solar wind, [PHYS.PHYS.PHYS-PLASM-PH]Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph], Physics::Space Physics, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, General Earth and Planetary Sciences, Magnetopause, Energy transformation, Astrophysics::Earth and Planetary Astrophysics, Magnetospheric Multiscale Mission, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics, 0105 earth and related environmental sciences
Abstract

International audience; Data from the NASA Magnetospheric Multiscale mission are used to investigate asymmetric magnetic reconnection at the dayside boundary between the Earth's magnetosphere and the solar wind. High-resolution measurements of plasmas and fields are used to identify highly localized ( 15 electron Debye lengths) standing wave structures with large electric field amplitudes (up to 100 mV/m). These wave structures are associated with spatially oscillatory energy conversion, which appears as alternatingly positive and negative values of J · E. For small guide magnetic fields the wave structures occur in the electron stagnation region at the magnetosphere edge of the electron diffusion region. For larger guide fields the structures also occur near the reconnection X-line. This difference is explained in terms of channels for the out-of-plane current (agyrotropic electrons at the stagnation point and guide field-aligned electrons at the X-line).

Published
2018

27. Electron diffusion region during magnetopause reconnection with an intermediate guide field: Magnetospheric multiscale observations

Author

Naoki Bessho, Shan Wang, Roy B. Torbert, Yu. V. Khotyaintsev, Daniel J. Gershman, William R. Paterson, Christopher T. Russell, Craig J. Pollock, James Webster, Benoit Lavraud, Per-Arne Lindqvist, James L. Burch, L. J. Chen, Robert E. Ergun, Robert J. Strangeway, Barbara L. Giles, John C. Dorelli, Thomas E. Moore, Levon A. Avanov, Michael Hesse, 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), 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, electron acceleration, 010504 meteorology & atmospheric sciences, Field (physics), electron diffusion region, Magnetic reconnection, Electron, Geophysics, Space (mathematics), 01 natural sciences, Magnetic field, Electron acceleration, diffusion region, [SDU]Sciences of the Universe [physics], Space and Planetary Science, magnetic reconnection, Physics::Space Physics, 0103 physical sciences, electric field acceleration, Astrophysics::Solar and Stellar Astrophysics, Magnetopause, Diffusion (business), 010303 astronomy & astrophysics, 0105 earth and related environmental sciences
Abstract

International audience; An electron diffusion region (EDR) in magnetic reconnection with a guide magnetic field approximately 0.2 times the reconnecting component is encountered by the four Magnetospheric Multiscale spacecraft at the Earth's magnetopause. The distinct substructures in the EDR on both sides of the reconnecting current sheet are visualized with electron distribution functions that are 2 orders of magnitude higher cadence than ever achieved to enable the following new findings: (1) Motion of the demagnetized electrons plays an important role to sustain the reconnection current and contributes to the dissipation due to the nonideal electric field, (2) the finite guide field dominates over the Hall magnetic field in an electron-scale region in the exhaust and modifies the electron flow dynamics in the EDR, (3) the reconnection current is in part carried by inflowing field-aligned electrons in the magnetosphere part of the EDR, and (4) the reconnection electric field measured by multiple spacecraft is uniform over at least eight electron skin depths and corresponds to a reconnection rate of approximately 0.1. The observations establish the first look at the structure of the EDR under a weak but not negligible guide field.

Published
2017

28. Drift waves, intense parallel electric fields, and turbulence associated with asymmetric magnetic reconnection at the magnetopause

Author

Barbara L. Giles, Steven J. Schwartz, Matthew R. Argall, Rumi Nakamura, L. Price, Justin Holmes, J. Webster, Levon A. Avanov, Robert J. Strangeway, Roy B. Torbert, John C. Dorelli, Alessandro Retinò, Narges Ahmadi, Jonathan Eastwood, K. A. Goodrich, Stefan Eriksson, Julia E. Stawarz, Shan Wang, L. J. Chen, O. Le Contel, Michael Hesse, Benoit Lavraud, Daniel J. Gershman, Per-Arne Lindqvist, Martin V. Goldman, David M. Malaspina, Marc Swisdak, Kyoung-Joo Hwang, James L. Burch, A. P. Sturner, Michael Shay, James Drake, Robert E. Ergun, David Newman, Frederick Wilder, Daniel B. Graham, Christopher T. Russell, T. D. Phan, Paul Cassak, and Maria Usanova

Subjects
Physics, 010504 meteorology & atmospheric sciences, Turbulence, Magnetic reconnection, Geophysics, Dissipation, 01 natural sciences, Instability, Magnetic field, 13. Climate action, Electric field, Quantum electrodynamics, Physics::Space Physics, 0103 physical sciences, General Earth and Planetary Sciences, Magnetopause, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences
Abstract

Observations of magnetic reconnection at Earth's magnetopause often display asymmetric structures that are accompanied by strong magnetic field (B) fluctuations and large-amplitude parallel electri ...

Published
2017

29. Performance of a space‐based wavelet compressor for plasma count data on the MMS Fast Plasma Investigation

Author

A. C. Barrie, John C. Dorelli, P. Yeh, Daniel J. Gershman, Levon A. Avanov, C. Schiff, and S. E. Smith

Subjects
Discrete wavelet transform, Lossless compression, 010504 meteorology & atmospheric sciences, Computer science, Data compression ratio, 01 natural sciences, Geophysics, Wavelet, Space and Planetary Science, Compression (functional analysis), 0103 physical sciences, Compression ratio, 010303 astronomy & astrophysics, Algorithm, 0105 earth and related environmental sciences, Data compression, Bit plane
Abstract

Data compression has been a staple of imaging instruments for years. Recently, plasma measurements have utilized compression with relatively low compression ratios. The Fast Plasma Investigation [Pollock et. al., 2016] (FPI) on board the Magnetospheric Multiscale (MMS) mission generates data roughly 100 times faster than previous plasma instruments, requiring a higher compression ratio to fit within the telemetry allocation. This study investigates the performance of a space-based compression standard employing a Discrete Wavelet Transform and a Bit Plane Encoder [CCSDS, 2005] (DWT/BPE) in compressing FPI plasma count data. Data from the first six months of FPI operation are analyzed to explore the error modes evident in the data and how to adapt to them. While approximately half of the DES maps had some level of loss, it was found that there is little effect on the plasma moments and that errors present in individual sky maps are typically minor. The majority of DIS burst sky maps compressed in a lossless fashion, with no error introduced during compression. Because of induced compression error, the size limit for DES burst images has been increased for Phase 1B. Additionally, it was found that the floating point compression mode yielded better results when images have significant compression error, leading to floating point mode being used for the Fast Survey mode of operation for Phase 1B. Despite the suggested tweaks, it was found that wavelet based compression, and a DWT/BPE algorithm in particular, is highly suitable to data compression for plasma measurement instruments and can be recommended for future missions.

Published
2017

30. Pressure Tensor Elements Breaking the Frozen-In Law During Reconnection in Earth’s Magnetotail

Author

William Daughton, D. J. Gershman, Ari Le, Blake Wetherton, John C. Dorelli, A. C. Rager, Jonathan Ng, and Jan Egedal

Subjects
Physics, Spacecraft, business.industry, General Physics and Astronomy, Magnetic reconnection, Electron, Kinetic energy, 01 natural sciences, Stress (mechanics), Law, Physics::Space Physics, 0103 physical sciences, Tensor, Diffusion (business), 010306 general physics, business, Earth (classical element)
Abstract

Aided by fully kinetic simulations, spacecraft observations of magnetic reconnection in Earth's magnetotail are analyzed. The structure of the electron diffusion region is in quantitative agreement with the numerical model. Of special interest, the spacecraft data reveal how reconnection is mediated by off-diagonal stress in the electron pressure tensor breaking the frozen-in law of the electron fluid.

Published
2019

31. 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

32. Does the Solar Wind Electric Field Control the Reconnection Rate at Earth's Subsolar Magnetopause?

Author

John C. Dorelli

Subjects
Physics, Astrophysics::High Energy Astrophysical Phenomena, Magnetosphere, Magnetic reconnection, Bow shocks in astrophysics, Magnetic flux, Computational physics, Solar wind, Geophysics, Earth's magnetic field, Space and Planetary Science, Electric field, Physics::Space Physics, Astrophysics::Solar and Stellar Astrophysics, Magnetopause, Astrophysics::Earth and Planetary Astrophysics
Abstract

We demonstrate that the reconnection rate at the subsolar magnetopause is stronglycontrolled by the solar wind electric field and depends weakly on the local properties of the dissipationregion. Our approach is to match the solar wind and magnetospheric states in an internal boundarylayer described by the Cassak and Shay (2007, https://doi.org/10.1063/1.2795630) expression fortwo-dimensional asymmetric reconnection. Faraday's law along the Sun-Earth line determinesthe variation of the solar wind electric field from the bow shock to the magnetopause. While themagnetospheric plasma exerts some control over the reconnection rate, magnetic flux pileup in the sheathpartially compensates for any local reduction in the reconnection rate. For a fixed magnetospheric state,the reconnection rate is shown to be directly proportional to the solar wind electric field, thus explainingwhy the solar wind electric field correlates well with geomagnetic indices.

Published
2019

33. Publisher Correction: Electron magnetic reconnection without ion coupling in Earth's turbulent magnetosheath

Author

O. Le Contel, Michael Shay, James L. Burch, Christopher T. Russell, Paul Cassak, T. D. Phan, Per-Arne Lindqvist, Marit Øieroset, Werner Magnes, C. J. Pollock, Frederick Wilder, Benoit Lavraud, A. C. Rager, Alessandro Retinò, Barbara L. Giles, Robert J. Strangeway, M. Fujimoto, Prayash Sharma Pyakurel, Roy B. Torbert, D. J. Gershman, Yoshitaka Saito, John C. Dorelli, Thomas E. Moore, Colby Haggerty, Bengt U. Ö. Sonnerup, Matthew R. Argall, Yu. V. Khotyaintsev, Robert E. Ergun, James Drake, Jonathan Eastwood, Mitsuo Oka, NASA Goddard Space Flight Center (GSFC), 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), Alfven Laboratory, Royal Institute of Technology [Stockholm] (KTH ), and Science and Technology Facilities Council (STFC)

Subjects
Physics, Coupling, 0303 health sciences, Multidisciplinary, 010405 organic chemistry, 030306 microbiology, Turbulence, General Science & Technology, Magnetic reconnection, Electron, 01 natural sciences, 0104 chemical sciences, Computational physics, Ion, 03 medical and health sciences, Current sheet, Magnetosheath, [PHYS.PHYS.PHYS-PLASM-PH]Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph], MD Multidisciplinary, Wrong direction, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

International audience; In Fig. 3f of this Letter, owing to an error in the production process, the y-axis values are incorrect, and should go from 4 to −8 (rather than from 4 to −4), and in Fig. 3h, the y-axis values (18, 20, 22, 24) should appear next to the major tick marks (rather than the minor ticks). In addition, in Fig. 1b, the arrows at the top and the bottom of the electron-scale current sheet were going in the wrong direction. These errors have been corrected online.

Published
2019

34. MMS Measurements of the Vlasov Equation: Probing the Electron Pressure Divergence Within Thin Current Sheets

Author

Richard E. Denton, C. Schiff, M. Swisdak, D. Da Silva, Naoki Bessho, S. E. Smith, Cecilia Norgren, Shan Wang, S. J. Schwartz, A. C. Rager, Levon A. Avanov, Barbara L. Giles, L. J. Chen, Frederick Wilder, John C. Dorelli, Adolfo F. Viñas, Vadim M. Uritsky, Paul Cassak, J. R. Shuster, D. J. Gershman, and W. R. Paterson

Subjects
Physics, Geophysics, Magnetosheath, Physics::Space Physics, Vlasov equation, General Earth and Planetary Sciences, Magnetopause, Diamagnetism, Electron, Current (fluid), Molecular physics, Current density, Magnetic field
Abstract

We investigate the kinetic structure of electron-scale current sheets found in the vicinity of the magnetopause and embedded in the magnetosheath within the reconnection exhaust. A new technique for computing terms of the Vlasov equation using Magnetospheric Multiscale (MMS) measurements is presented and applied to study phase space density gradients and the kinetic origins of the electron pressure divergence found within these current sheets. Crescent-shaped structures in ∇(⟂2)f(e) give rise to bipolar and quadrupolar signatures in v · ∇f(e) measured near the maximum ∇ · P(e) inside the current layers. The current density perpendicular to the magnetic field is strong (J⟂ ∼2 μA/sq.m), and the thickness of the current layers ranges from 3 to 5 electron inertial lengths. The electron flows supporting the current layers mainly result from the combination of E × B and diamagnetic drifts. We find nonzero J · E′ within the current sheets even though they are observed apart from typical diffusion region signatures.

Published
2019

35. Four-Spacecraft Measurements of the Shape and Dimensionality of Magnetic Structures in the Near-Earth Plasma Environment

Author

Christian Jacquey, Christopher Russell, Craig J. Pollock, E. Penou, Tai Phan, Charlie J. Farrugia, Francesco Califano, I. Kacem, Hiroshi Hasegawa, Thomas E. Moore, J-A Sauvaud, Rumi Nakamura, Benoit Lavraud, M. O. Chandler, John C. Dorelli, Yuri V. Khotyaintsev, S. Toledo Redondo, Barbara L. Giles, Levon A. Avanov, William R. Paterson, D. J. Gershman, Y. Vernisse, Shan Wang, Jonathan Eastwood, V. N. Coffey, S. A. Fuselier, Robert E. Ergun, Yoshifumi Saito, S. E. Smith, S. Fadanelli, C. Schiff, Elena Grigorenko, Roy B. Torbert, A. C. Rager, O. Le Contel, Shoichiro Yokota, Aurélie Marchaudon, Vincent Génot, James L. Burch, 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), University of Pisa - Università di Pisa, NASA Goddard Space Flight Center (GSFC), NASA Marshall Space Flight Center (MSFC), Laboratoire de Physique des Plasmas (LPP), 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), Science and Technology Facilities Council (STFC), 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), 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), PIBERNE, Rodrigue, and Dipartimento di Fisica 'E Fermi' & CNISM

Subjects
Physics, 010504 meteorology & atmospheric sciences, Spacecraft, business.industry, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Plasma, Magnetic field gradient, 01 natural sciences, [PHYS.PHYS.PHYS-SPACE-PH]Physics [physics]/Physics [physics]/Space Physics [physics.space-ph], Computational physics, Magnetic field, Geophysics, Space and Planetary Science, [PHYS.PHYS.PHYS-PLASM-PH]Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph], [PHYS.PHYS.PHYS-PLASM-PH] Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph], 0103 physical sciences, business, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], [PHYS.ASTR] Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics, Earth (classical element), ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Curse of dimensionality
Abstract

著者人数: 39名 (所属. 宇宙航空研究開発機構宇宙科学研究所(JAXA)(ISAS): 長谷川, 洋; 齋藤, 義文), Number of authors: 39 (Affiliation. Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency(JAXA)(ISAS): Hasegawa, Hiroshi; Saito, Yoshifumi), Accepted: 2019-06-10, 資料番号: SA1190161000

Published
2019

36. Strong current sheet at a magnetosheath jet: Kinetic structure and electron acceleration

Author

Andris Vaivads, Craig J. Pollock, Daniel J. Gershman, William R. Paterson, Yuri V. Khotyaintsev, Roy Torbert, Levon A. Avanov, Barbara L. Giles, Emiliya Yordanova, Robert E. Ergun, Christopher T. Russell, Mats André, Benoit Lavraud, Yoshitaka Saito, Heli Hietala, Per-Arne Lindqvist, John C. Dorelli, Werner Magnes, Elin Eriksson, Daniel B. Graham, James L. Burch, 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), 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
010504 meteorology & atmospheric sciences, 01 natural sciences, Fusion, plasma och rymdfysik, Current sheet, Magnetosheath, current sheet, 0103 physical sciences, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, thermalization, Physics, Jet (fluid), electron acceleration, magnetosheath jet, Plasma, Bow shocks in astrophysics, magnetosheath, Fusion, Plasma and Space Physics, Particle acceleration, Solar wind, Geophysics, [SDU]Sciences of the Universe [physics], Space and Planetary Science, Physics::Space Physics, reconnection, Heliospheric current sheet, Atomic physics
Abstract

International audience; Localized kinetic-scale regions of strong current are believed to play an important role in plasma thermalization and particle acceleration in turbulent plasmas. We present a detailed study of a strong localized current, 4900 nA m-2, located at a fast plasma jet observed in the magnetosheath downstream of a quasi-parallel shock. The thickness of the current region is ∼3 ion inertial lengths and forms at a boundary separating magnetosheath-like and solar wind-like plasmas. On ion scales the current region has the shape of a sheet with a significant average normal magnetic field component but shows strong variations on smaller scales. The dynamic pressure within the magnetosheath jet is over 3 times the solar wind dynamic pressure. We suggest that the current sheet is forming due to high velocity shears associated with the jet. Inside the current sheet we observe local electron acceleration, producing electron beams, along the magnetic field. However, there is no clear sign of ongoing reconnection. At higher energies, above the beam energy, we observe a loss cone consistent with part of the hot magnetosheath-like electrons escaping into the colder solar wind-like plasma. This suggests that the acceleration process within the current sheet is similar to the one that occurs at shocks, where electron beams and loss cones are also observed. Therefore, electron beams observed in the magnetosheath do not have to originate from the bow shock but can also be generated locally inside the magnetosheath.

Published
2016

37. The substructure of a flux transfer event observed by the MMS spacecraft

Author

Christopher T. Russell, Robert E. Ergun, Barry Mauk, William R. Paterson, Robert J. Strangeway, Roy B. Torbert, Levon A. Avanov, Barbara L. Giles, K.-J. Hwang, John C. Dorelli, D. J. Gershman, David G. Sibeck, James L. Burch, C. J. Pollock, and Ian J. Cohen

Subjects
Physics, 010504 meteorology & atmospheric sciences, Field line, Magnetosphere, Flux, Geophysics, 01 natural sciences, Computational physics, Magnetic field, Magnetosheath, Physics::Space Physics, 0103 physical sciences, General Earth and Planetary Sciences, Flux transfer event, Magnetopause, Magnetospheric Multiscale Mission, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences
Abstract

On 15 August 2015, MMS (Magnetospheric Multiscale mission), skimming the dusk magnetopause, detected an isolated region of an increased magnetic strength and bipolar Bn, indicating a flux transfer event (FTE). The four spacecraft in a tetrahedron allowed for investigations of the shape and motion of the FTE. In particular, high-resolution particle data facilitated our exploration of FTE substructures and their magnetic connectivity inside and surrounding the FTE. Combined field and plasma observations suggest that the core fields are open, magnetically connected to the northern magnetosphere from which high-energy particles leak; ion "D" distributions characterize the axis of flux ropes that carry old-opened field lines; counter streaming electrons superposed by parallel-heated components populate the periphery surrounding the FTE; and the interface between the core and draped regions contains a separatrix of newlyopened magnetic field lines that emanate from the X line above the FTE.

Published
2016

38. Energy limits of electron acceleration in the plasma sheet during substorms: A case study with the Magnetospheric Multiscale (MMS) mission

Author

Rumi Nakamura, Daniel Schmid, Drew Turner, Roy B. Torbert, Geoffrey D. Reeves, Levon A. Avanov, Christopher T. Russell, Robert J. Strangeway, John C. Dorelli, Andrei Runov, Craig J. Pollock, Daniel N. Baker, Frederick Wilder, Barry Mauk, Ian J. Cohen, Allison Jaynes, J. B. Blake, Barbara L. Giles, Harlan E. Spence, James L. Burch, D. J. Gershman, J. V. Craft, J. F. Fennell, Vassilis Angelopoulos, A. V. Artemyev, and J. H. Clemmons

Subjects
Physics, Range (particle radiation), 010504 meteorology & atmospheric sciences, Astrophysics::High Energy Astrophysical Phenomena, Plasma sheet, Electron, Geophysics, Threshold energy, Betatron, 01 natural sciences, Computational physics, Particle acceleration, Physics::Space Physics, 0103 physical sciences, Substorm, General Earth and Planetary Sciences, Magnetospheric Multiscale Mission, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences
Abstract

We present multipoint observations of earthward moving dipolarization fronts and energetic particle injections from NASA's Magnetospheric Multiscale mission with a focus on electron acceleration. From a case study during a substorm on 02 August 2015, we find that electrons are only accelerated over a finite energy range, from a lower energy threshold at ~7–9 keV up to an upper energy cutoff in the hundreds of keV range. At energies lower than the threshold energy, electron fluxes decrease, potentially due to precipitation by strong parallel electrostatic wavefields or initial sources in the lobes. Electrons at energies higher than the threshold are accelerated cumulatively by a series of impulsive magnetic dipolarization events. This case demonstrates how the upper energy cutoff increases, in this case from ~130 keV to >500 keV, with each dipolarization/injection during sustained activity. We also present a simple model accounting for these energy limits that reveals that electron energization is dominated by betatron acceleration.

Published
2016

39. Cold ion demagnetization near the X-line of magnetic reconnection

Author

Michael O. Chandler, Wenya Li, Thomas E. Moore, Roy B. Torbert, Yuri V. Khotyaintsev, Daniel J. Gershman, Sergio Toledo-Redondo, Mats André, Yoshifumi Saito, John C. Dorelli, Daniel B. Graham, Christopher T. Russell, Andrew Walsh, Barbara L. Giles, Benoit Lavraud, Per-Arne Lindqvist, Craig J. Pollock, Stephen A. Fuselier, Andrey Divin, Levon A. Avanov, Jérémy Dargent, Nicolas Aunai, Arnaud Masson, Andris Vaivads, and Victoria N. Coffey

Subjects
Physics, 010504 meteorology & atmospheric sciences, Demagnetizing field, Magnetic reconnection, Electron, Plasma, 01 natural sciences, Geophysics, Magnetosheath, Physics::Plasma Physics, Electric field, Physics::Space Physics, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, General Earth and Planetary Sciences, Magnetopause, Atomic physics, 010303 astronomy & astrophysics, Computer Science::Databases, 0105 earth and related environmental sciences, Line (formation)
Abstract

Although the effects of magnetic reconnection in magnetospheres can be observed at planetary scales, reconnection is initiated at electron scales in a plasma. Surrounding the electron diffusion reg ...

Published
2016

40. Finite gyroradius effects in the electron outflow of asymmetric magnetic reconnection

Author

Werner Magnes, Per-Arne Lindqvist, Benoit Lavraud, Robert J. Strangeway, Göran Marklund, Yuri V. Khotyaintsev, James L. Burch, Yoshitaka Saito, Cecilia Norgren, Christopher T. Russell, Barbara L. Giles, Levon A. Avanov, Robert E. Ergun, Daniel J. Gershman, William R. Paterson, John C. Dorelli, Roy B. Torbert, L. J. Chen, Craig J. Pollock, Daniel B. Graham, Andris Vaivads, and Mats André

Subjects
Physics, 010504 meteorology & atmospheric sciences, Condensed matter physics, Gyroradius, Demagnetizing field, Magnetic reconnection, Electron, 01 natural sciences, Geophysics, Physics::Space Physics, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, General Earth and Planetary Sciences, Magnetopause, Outflow, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences
Abstract

We present observations of asymmetric magnetic reconnection showing evidence of electron demagnetization in the electron outflow. The observations were made at the magnetopause by the four Magnetos ...

Published
2016

41. Magnetic reconnection and modification of the Hall physics due to cold ions at the magnetopause

Author

John C. Dorelli, Mats André, Göran Marklund, James L. Burch, Christopher T. Russell, Michael O. Chandler, Yoshitaka Saito, T. E. Moore, Per-Arne Lindqvist, Wenya Li, Daniel J. Gershman, William R. Paterson, Cecilia Norgren, Sergio Toledo-Redondo, Andris Vaivads, Barbara L. Giles, Levon A. Avanov, Benoit Lavraud, Robert E. Ergun, D. T. Young, Craig J. Pollock, Werner Magnes, Yuri V. Khotyaintsev, Daniel B. Graham, and Roy Torbert

Subjects
Physics, Ohm's law, 010504 meteorology & atmospheric sciences, Condensed matter physics, Thermal Hall effect, Magnetic reconnection, Electron, 01 natural sciences, symbols.namesake, Geophysics, Physics::Plasma Physics, Hall effect, Electric field, Physics::Space Physics, 0103 physical sciences, symbols, General Earth and Planetary Sciences, Magnetopause, Electric current, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences
Abstract

Observations by the four Magnetospheric Multiscale spacecraft are used to investigate the Hall physics of a magnetopause magnetic reconnection separatrix layer. Inside this layer of currents and st ...

Published
2016

42. A telescopic and microscopic examination of acceleration in the June 2015 geomagnetic storm: Magnetospheric Multiscale and Van Allen Probes study of substorm particle injection

Author

Robert J. Strangeway, Rumi Nakamura, Ian J. Cohen, Allison Jaynes, Barry Mauk, John C. Dorelli, Christopher T. Russell, J. B. Blake, D. J. Gershman, Drew Turner, Daniel N. Baker, Roy B. Torbert, J. F. Fennell, James L. Burch, Barbara L. Giles, and Daniel Schmid

Subjects
Geomagnetic storm, Physics, 010504 meteorology & atmospheric sciences, Magnetosphere, Geophysics, Space weather, 01 natural sciences, Solar wind, symbols.namesake, Van Allen radiation belt, Physics::Space Physics, 0103 physical sciences, Substorm, symbols, General Earth and Planetary Sciences, Van Allen Probes, Interplanetary magnetic field, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences
Abstract

An active storm period in June 2015 showed that particle injection events seen sequentially by the four (MagnetosphericMultiscale) MMS spacecraft subsequently fed the enhancement of the outer radiation belt observed by Van Allen Probes mission sensors. Several episodes of significant southward interplanetary magnetic field along with a period of high solar wind speed (Vsw 500kms) on 22 June occurred following strong interplanetary shock wave impacts on the magnetosphere. Key events on 22 June 2015 show that the magnetosphere progressed through a sequence of energy-loading and stress-developing states until the entire system suddenly reconfigured at 19:32 UT. Energetic electrons, plasma, and magnetic fields measured by the four MMS spacecraft revealed clear dipolarization front characteristics. It was seen that magnetospheric substorm activity provided a seed electron population as observed by MMS particle sensors as multiple injections and related enhancements in electron flux.

Published
2016

43. Thick escaping magnetospheric ion layer in magnetopause reconnection with MMS observations

Author

Mitsuo Oka, Rumi Nakamura, Levon A. Avanov, James L. Burch, Craig J. Pollock, Iku Shinohara, Kevin Genestreti, Barbara L. Giles, John C. Dorelli, Daniel J. Gershman, William R. Paterson, Michael O. Chandler, J. A. Sauvaud, Naritoshi Kitamura, Hiroshi Hasegawa, Christopher T. Russell, Thomas E. Moore, Robert J. Strangeway, Yoshifumi Saito, Victoria N. Coffey, Tsugunobu Nagai, Shoichiro Yokota, and Benoit Lavraud

Subjects
Physics, 010504 meteorology & atmospheric sciences, Field line, Magnetosphere, Magnetic reconnection, Geophysics, Astrophysics, 01 natural sciences, Ion, Magnetic field, Magnetosheath, Physics::Plasma Physics, Physics::Space Physics, 0103 physical sciences, General Earth and Planetary Sciences, Magnetopause, Magnetospheric Multiscale Mission, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences
Abstract

The structure of asymmetric magnetopause reconnection is explored with multiple point and high-time-resolution ion velocity distribution observations from the Magnetospheric Multiscale mission. On 9 September 2015, reconnection took place at the magnetopause, which separated the magnetosheath and the magnetosphere with a density ratio of 25:2. The magnetic field intensity was rather constant, even higher in the asymptotic magnetosheath. The reconnected field line region had a width of approximately 540 km. In this region, streaming and gyrating ions are discriminated. The large extension of the reconnected field line region toward the magnetosheath can be identified where a thick layer of escaping magnetospheric ions was formed. The scale of the magnetosheath side of the reconnected field line region relative to the scale of its magnetospheric side was 4.5:1.

Published
2016

44. Electron energization and mixing observed by MMS in the vicinity of an electron diffusion region during magnetopause reconnection

Author

John C. Dorelli, Benoit Lavraud, William Daughton, Robert E. Ergun, Yuri V. Khotyaintsev, Naoki Bessho, Shan Wang, Thomas E. Moore, Craig J. Pollock, Levon A. Avanov, Barbara L. Giles, Robert J. Strangeway, Tai Phan, James L. Burch, Roy B. Torbert, Christopher T. Russell, Michael Hesse, Li-Jen Chen, and Daniel J. Gershman

Subjects
Physics, 010504 meteorology & atmospheric sciences, Magnetic reconnection, Electron, 01 natural sciences, Computational physics, Magnetic field, Particle acceleration, Geophysics, Electric field, Physics::Space Physics, 0103 physical sciences, General Earth and Planetary Sciences, Magnetopause, Atomic physics, 010303 astronomy & astrophysics, Magnetosphere particle motion, Mixing (physics), 0105 earth and related environmental sciences
Abstract

Measurements from the Magnetospheric Multiscale (MMS) mission are reported to show distinct features of electron energization and mixing in the diffusion region of the terrestrial magnetopause reconnection. At the ion jet and magnetic field reversals, distribution functions exhibiting signatures of accelerated meandering electrons are observed at an electron out-of-plane flow peak. The meandering signatures manifested as triangular and crescent structures are established features of the electron diffusion region (EDR). Effects of meandering electrons on the electric field normal to the reconnection layer are detected. Parallel acceleration and mixing of the inflowing electrons with exhaust electrons shape the exhaust flow pattern. In the EDR vicinity, the measured distribution functions indicate that locally, the electron energization and mixing physics is captured by two-dimensional reconnection, yet to account for the simultaneous four-point measurements, translational invariant in the third dimension must be violated on the ion-skin-depth scale.

Published
2016

45. Magnetospheric Multiscale Mission observations and non-force free modeling of a flux transfer event immersed in a super-Alfvénic flow

Author

Wenyuan Yu, Charlie J. Farrugia, S. A. Fuselier, I. Kacem, Per-Arne Lindqvist, J. R. Shuster, Robert J. Strangeway, Göran Marklund, Robert E. Ergun, Roy B. Torbert, L. Alm, Matthew R. Argall, John C. Dorelli, Yu. V. Khotyaintsev, Hiroshi Matsui, D. J. Gershman, Christopher T. Russell, Barbara L. Giles, Jonathan Eastwood, Benoit Lavraud, Craig J. Pollock, James L. Burch, Kristoff Paulson, and Tai Phan

Subjects
Physics, 010504 meteorology & atmospheric sciences, Plasma, Geophysics, Mechanics, 01 natural sciences, Magnetic field, Physics::Plasma Physics, Electric field, Physics::Space Physics, 0103 physical sciences, General Earth and Planetary Sciences, Magnetopause, Flux transfer event, Dynamic pressure, Transient (oscillation), Magnetospheric Multiscale Mission, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences
Abstract

We analyze plasma, magnetic field, and electric field data for a flux transfer event (FTE) to highlight improvements in our understanding of these transient reconnection signatures resulting from h ...

Published
2016

46. Whistler mode waves and Hall fields detected by MMS during a dayside magnetopause crossing

Author

James L. Burch, Christopher T. Russell, Kenneth R. Bromund, Daniel B. Graham, T. Chust, D. J. Gershman, Ferdinand Plaschke, Alexandros Chasapis, Roy B. Torbert, Thomas E. Moore, Brian J. Anderson, Alessandro Retinò, D. Rau, I. Dors, Levon A. Avanov, L. Mirioni, Robert J. Strangeway, Per-Arne Lindqvist, Robert E. Ergun, Laurence Rezeau, Craig J. Pollock, Hugo Breuillard, M. Chutter, Hannes K. Leinweber, John C. Dorelli, P. Robert, Guan Le, Benoit Lavraud, Yu. V. Khotyaintsev, Frederick Wilder, J. Needell, Matthew R. Argall, Göran Marklund, Yoshitaka Saito, O. Le Contel, Barbara L. Giles, Werner Magnes, David Fischer, and K. A. Goodrich

Subjects
Physics, Ion flow, 010504 meteorology & atmospheric sciences, Separatrix, Astrophysics::High Energy Astrophysical Phenomena, Geophysics, 01 natural sciences, Physics::Plasma Physics, Physics::Space Physics, 0103 physical sciences, General Earth and Planetary Sciences, Magnetopause, Whistler mode, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences
Abstract

We present Magnetospheric Multiscale (MMS) mission measurements during a full magnetopause crossing associated with an enhanced southward ion flow. A quasi-steady magnetospheric whistler mode wave ...

Published
2016

47. Ion-scale structure in Mercury's magnetopause reconnection diffusion region

Author

John C. Dorelli, Thomas H. Zurbuchen, Gangkai Poh, Jim M. Raines, Gina A. DiBraccio, James A. Slavin, and Daniel J. Gershman

Subjects
Physics, 010504 meteorology & atmospheric sciences, Magnetosphere, Magnetic reconnection, Geophysics, 01 natural sciences, Magnetic flux, Magnetic field, Computational physics, Solar wind, Physics::Space Physics, 0103 physical sciences, General Earth and Planetary Sciences, Flux transfer event, Magnetopause, Astrophysics::Earth and Planetary Astrophysics, Mercury's magnetic field, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences
Abstract

The strength and time dependence of the electric field in a magnetopause diffusion region relate to the rate of magnetic reconnection between the solar wind and a planetary magnetic field. Here we use approximately 150 milliseconds measurements of energetic electrons from the Mercury Surface, Space Environment, GEochemistry, and Ranging (MESSENGER) spacecraft observed over Mercury's dayside polar cap boundary (PCB) to infer such small-scale changes in magnetic topology and reconnection rates. We provide the first direct measurement of open magnetic topology in flux transfer events at Mercury, structures thought to account for a significant portion of the open magnetic flux transport throughout the magnetosphere. In addition, variations in PCB latitude likely correspond to intermittent bursts of approximately 0.3 to 3 millivolts per meter reconnection electric fields separated by approximately 5 to10 seconds, resulting in average and peak normalized dayside reconnection rates of approximately 0.02 and approximately 0.2, respectively. These data demonstrate that structure in the magnetopause diffusion region at Mercury occurs at the smallest ion scales relevant to reconnection physics.

Published
2016

48. Estimates of terms in Ohm's law during an encounter with an electron diffusion region

Author

Per-Arne Lindqvist, Frederick Wilder, Roy B. Torbert, Thomas E. Moore, Matthew R. Argall, H. A. Faith, K. A. Goodrich, Craig Kletzing, Charlie J. Farrugia, John C. Dorelli, Christopher T. Russell, James L. Burch, T. D. Phan, Werner Magnes, Robert J. Strangeway, William Daughton, Daniel J. Gershman, Göran Marklund, Scott R. Bounds, J. R. Shuster, Robert E. Ergun, Levon A. Avanov, Yu. V. Khotyaintsev, Barbara L. Giles, and Craig J. Pollock

Subjects
Physics, Ohm's law, 010504 meteorology & atmospheric sciences, Geophysics, Electron, Dissipation, 01 natural sciences, Computational physics, symbols.namesake, Physics::Space Physics, 0103 physical sciences, symbols, General Earth and Planetary Sciences, Magnetopause, Astrophysics::Earth and Planetary Astrophysics, Diffusion (business), 010303 astronomy & astrophysics, Event (particle physics), Pressure gradient, 0105 earth and related environmental sciences, Three dimensional model
Abstract

We present measurements from the Magnetospheric Multiscale (MMS) mission taken during a reconnection event on the dayside magnetopause which includes a passage through an electron diffusion region ...

Published
2016

49. Magnetospheric Multiscale observations of large-amplitude, parallel, electrostatic waves associated with magnetic reconnection at the magnetopause

Author

Benoit Lavraud, P. A. Lindqvist, Paul Cassak, Julia E. Stawarz, John C. Dorelli, Levon A. Avanov, David M. Malaspina, James L. Burch, K. A. Goodrich, Christopher T. Russell, O. Le Contel, Martin V. Goldman, Yuri V. Khotyaintsev, Steven J. Schwartz, T. D. Phan, Matthew R. Argall, Mats André, L. J. Chen, Roy B. Torbert, Maha Ashour-Abdalla, Robert J. Strangeway, Michael Shay, Barbara L. Giles, Alessandro Retinò, Rumi Nakamura, Frederick Wilder, David Newman, Craig J. Pollock, A. P. Sturner, Maria Usanova, Michael Hesse, James Drake, Marit Øieroset, Justin Holmes, Robert E. Ergun, Jonathan Eastwood, Stefan Eriksson, and Meng Zhou

Subjects
Physics, 010504 meteorology & atmospheric sciences, Parallel flow, Magnetic reconnection, Geophysics, 01 natural sciences, Magnetosheath, Amplitude, Physics::Plasma Physics, Electric field, Physics::Space Physics, 0103 physical sciences, Ionic diffusion, General Earth and Planetary Sciences, Magnetopause, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences
Abstract

We report observations from the Magnetospheric Multiscale satellites of large-amplitude, parallel, electrostatic waves associated with magnetic reconnection at the Earth's magnetopause. The observe ...

Published
2016

50. Shift of the magnetopause reconnection line to the winter hemisphere under southward IMF conditions: Geotail and MMS observations

Author

Tsugunobu Nagai, Benoit Lavraud, John C. Dorelli, William R. Paterson, James L. Burch, Roy B. Torbert, Iku Shinohara, Hiroshi Hasegawa, Levon A. Avanov, J. A. Sauvaud, V. N. Coffey, Thomas E. Moore, M. O. Chandler, Shoichiro Yokota, Yoshifumi Saito, Robert J. Strangeway, Naritoshi Kitamura, Craig J. Pollock, D. J. Gershman, Christopher Russell, and Barbara L. Giles

Subjects
Physics, 010504 meteorology & atmospheric sciences, Subsolar point, Magnetic reconnection, Geophysics, 01 natural sciences, Current sheet, Magnetosheath, Earth's magnetic field, Physics::Space Physics, 0103 physical sciences, General Earth and Planetary Sciences, Magnetopause, Interplanetary magnetic field, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Line (formation)
Abstract

At 02:13 UT on 18 November 2015 when the geomagnetic dipole was tilted by -27deg, the MMS spacecraft observed southward reconnection jets near the subsolar magnetopause under southward and dawnward interplanetary magnetic field conditions. Based on four-spacecraft estimations of the magnetic field direction near the separatrix and the motion and direction of the current sheet, the location of the reconnection line was estimated to be approx.1.8 R(sub E) or further northward of MMS. The Geotail spacecraft at GSM Z approx. 1.4 R(sub E) also observed southward reconnection jets at the dawnside magnetopause 30-40 min later. The estimated reconnection line location was northward of GSM Z approx.2 R(sub E). This crossing occurred when MMS observed purely southward magnetic fields in the magnetosheath. The simultaneous observations are thus consistent with the hypothesis that the dayside magnetopause reconnection line shifts from the subsolar point toward the northem (winter) hemisphere due to the effect of geomagnetic dipole tilt.

Published
2016

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