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Start Over Author "P. Louarn" Topic 0105 earth and related environmental sciences
34 results on '"P. Louarn"'

1. Magnetic reconnection as a mechanism to produce multiple thermal proton populations and beams locally in the solar wind

Author

B. Lavraud, R. Kieokaew, N. Fargette, P. Louarn, A. Fedorov, N. André, G. Fruit, V. Génot, V. Réville, A. P. Rouillard, I. Plotnikov, E. Penou, A. Barthe, L. Prech, C. J. Owen, R. Bruno, F. Allegrini, M. Berthomier, D. Kataria, S. Livi, J. M. Raines, R. D’Amicis, J. P. Eastwood, C. Froment, R. Laker, M. Maksimovic, F. Marcucci, S. Perri, D. Perrone, T. D. Phan, D. Stansby, J. Stawarz, S. Toledo-Redondo, A. Vaivads, D. Verscharen, I. Zouganelis, V. Angelini, V. Evans, T. S. Horbury, H. O’Brien, 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), AKKA Technologies, Charles University [Prague] (CU), University College of London [London] (UCL), Laboratoire Population-Environnement-Développement (LPED), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU), The University of Texas at San Antonio (UTSA), 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), Mullard Space Science Laboratory (MSSL), University of Michigan [Ann Arbor], University of Michigan System, INAF - Osservatorio Astronomico di Roma (OAR), Istituto Nazionale di Astrofisica (INAF), Imperial College London, Laboratoire de Physique et Chimie de l'Environnement et de l'Espace (LPC2E), Observatoire des Sciences de l'Univers en région Centre (OSUC), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Università della Calabria [Arcavacata di Rende] (Unical), Italian Space Agency, Space Sciences Laboratory [Berkeley] (SSL), University of California [Berkeley], University of California-University of California, European Space Astronomy Centre (ESAC), European Space Agency (ESA), Royal Institute of Technology [Stockholm] (KTH ), 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), Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), University of California [Berkeley] (UC Berkeley), University of California (UC)-University of California (UC), Agence Spatiale Européenne = European Space Agency (ESA), Science and Technology Facilities Council (STFC), and The Royal Society

Subjects
astro-ph.SR, 010504 meteorology & atmospheric sciences, Proton, FOS: Physical sciences, Astrophysics, Astronomy & Astrophysics, 01 natural sciences, Nuclear physics, Physics - Space Physics, 0201 Astronomical and Space Sciences, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Sun: magnetic fields, Solar and Stellar Astrophysics (astro-ph.SR), 0105 earth and related environmental sciences, Physics, Computer Science::Information Retrieval, Astronomy and Astrophysics, Magnetic reconnection, Space Physics (physics.space-ph), Solar wind, Astrophysics - Solar and Stellar Astrophysics, solar wind, physics.space-ph, Space and Planetary Science, Physics::Space Physics, Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Mechanism (sociology)
Abstract

Context.Spacecraft data revealed early on the frequent observation of multiple near-thermal proton populations in the solar wind. Decades of research on their origin have focused on processes such as magnetic reconnection in the low corona and wave-particle interactions in the corona and locally in the solar wind.Aims.This study aims to highlight the fact that such multiple thermal proton populations and beams are also produced by magnetic reconnection occurring locally in the solar wind.Methods.We used high-resolution Solar Orbiter proton velocity distribution function measurements, complemented by electron and magnetic field data, to analyze the association of multiple thermal proton populations and beams with magnetic reconnection during a period of slow Alfvénic solar wind on 16 July 2020.Results.At least six reconnecting current sheets with associated multiple thermal proton populations and beams, including a case of magnetic reconnection at a switchback boundary, were found on this day. This represents 2% of the measured distribution functions. We discuss how this proportion may be underestimated, and how it may depend on solar wind type and distance from the Sun.Conclusions.Although suggesting a likely small contribution, but which remains to be quantitatively assessed, Solar Orbiter observations show that magnetic reconnection must be considered as one of the mechanisms that produce multiple thermal proton populations and beams locally in the solar wind.

Published
2021

2. Multiscale views of an Alfvénic slow solar wind: 3D velocity distribution functions observed by the Proton-Alpha Sensor of Solar Orbiter

Author

P. Louarn, A. Fedorov, L. Prech, C. J. Owen, R. Bruno, S. Livi, B. Lavraud, A. P. Rouillard, V. Génot, N. André, G. Fruit, V. Réville, R. Kieokaew, I. Plotnikov, E. Penou, A. Barthe, D. Khataria, M. Berthomier, R. D’Amicis, L. Sorriso-Valvo, F. Allegrini, J. Raines, D. Verscharen, V. Fortunato, G. Mele, T. S. Horbury, H. O’brien, V. Evans, V. Angelini, M. Maksimovic, J. C. Kasper, S. D. Bale, 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 Population-Environnement-Développement (LPED), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU), AKKA Technologies, 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), The University of Texas at San Antonio (UTSA), Southwest Research Institute [San Antonio] (SwRI), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)

Subjects
Physics, 010504 meteorology & atmospheric sciences, Proton, turbulence, Astronomy and Astrophysics, Astrophysics, plasmas, 01 natural sciences, Fusion, Plasma and Space Physics, Computational physics, law.invention, Solar wind, Orbiter, Fusion, plasma och rymdfysik, Distribution function, Astronomi, astrofysik och kosmologi, solar wind, Space and Planetary Science, law, 0103 physical sciences, Physics::Space Physics, Astronomy, Astrophysics and Cosmology, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics, 0105 earth and related environmental sciences
Abstract

Context.The Alfvénic slow solar wind is of particular interest, as it is often characterized by intense magnetic turbulence, complex proton 3D velocity distribution functions (VDF), and an ensuing richness of kinetic and dynamic processes.Aims.We take advantage of the fast time cadence of measurements taken by the Proton-Alpha Sensor (PAS) on board Solar Orbiter to analyze the kinetic properties of the proton population, the variability of their VDFs, and the possible link with propagating magnetic structures. We also study the magnetic (B) and velocity (V) correlation that characterizes this type of wind down to the ion gyroperiod.Methods.We analyzed the VDFs measured by PAS, a novelty that take advantages of the capability of 3D measurements at a 4 Hz cadence. In addition, we considered MAG observations.Results.We first show that there is a remarkable correlation between theBandVcomponents observed down to timescales approaching the ion gyrofrequency. This concerns a wide variety of fluctuations, such as waves, isolated peaks, and discontinuities. The great variability of the proton VDFs is also documented. The juxtaposition of a core and a field-aligned beam is the norm but the relative density of the beam, drift speed, and temperatures can considerably change on scales as short as as a few seconds. The characteristics of the core are comparatively more stable. These variations in the beam characteristics mostly explain the variations in the total parallel temperature and, therefore, in the total anisotropy of the proton VDFs. Two magnetic structures that are associated with significant changes in the shape of VDFs, one corresponding to relaxation of total anisotropy and the other to its strong increase, are analyzed here. Our statistical analysis shows a clear link between total anisotropy (and, thus, beam characteristics) and the direction ofBwith respect to the Parker spiral. In the present case, flux tubes aligned with Parker spiral contain an average proton VDF with a much more developed beam (thus, with larger total anisotropy) than those that are inclined, perpendicular, or even reverse with regard to the outward direction.Conclusions.These observations document the variability of the proton VDF shape in relation to the propagation of magnetic structures. This is a key area of interest for understanding of the effect of turbulence on solar wind dynamics.

Published
2021

3. First observations and performance of the RPW instrument on board the Solar Orbiter mission

Author

M. Maksimovic, J. Souček, T. Chust, Y. Khotyaintsev, M. Kretzschmar, X. Bonnin, A. Vecchio, O. Alexandrova, S. D. Bale, D. Bérard, J.-Y. Brochot, N. J. T. Edberg, A. Eriksson, L. Z. Hadid, E. P. G. Johansson, T. Karlsson, B. Katra, V. Krasnoselskikh, V. Krupař, S. Lion, E. Lorfèvre, L. Matteini, Q. N. Nguyen, D. Píša, R. Piberne, D. Plettemeier, H. O. Rucker, O. Santolík, K. Steinvall, M. Steller, Š. Štverák, P. Trávníček, A. Vaivads, A. Zaslavsky, S. Chaintreuil, M. Dekkali, P.-A. Astier, G. Barbary, K. Boughedada, B. Cecconi, F. Chapron, C. Collin, D. Dias, L. Guéguen, L. Lamy, V. Leray, L. R. Malac-Allain, F. Pantellini, J. Parisot, P. Plasson, S. Thijs, I. Fratter, E. Bellouard, P. Danto, S. Julien, E. Guilhem, C. Fiachetti, J. Sanisidro, C. Laffaye, F. Gonzalez, B. Pontet, N. Quéruel, G. Jannet, P. Fergeau, T. Dudok de Wit, T. Vincent, C. Agrapart, J. Pragout, M. Bergerard-Timofeeva, G. T. Delory, P. Turin, A. Jeandet, P. Leroy, J.-C. Pellion, V. Bouzid, W. Recart, I. Kolmašová, O. Krupařová, L. Uhlíř, R. Lán, J. Baše, M. André, L. Bylander, V. Cripps, C. Cully, S.-E. Jansson, W. Puccio, J. Břínek, H. Ottacher, V. Angelini, M. Berthomier, V. Evans, K. Goetz, P. Hellinger, T. S. Horbury, K. Issautier, E. Kontar, O. Le Contel, P. Louarn, M. Martinović, D. Müller, H. O’Brien, C. J. Owen, A. Retino, J. Rodríguez-Pacheco, F. Sahraoui, L. Sanchez, A. P. Walsh, R. F. Wimmer-Schweingruber, I. Zouganelis, Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), 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), Swedish Institute of Space Physics [Uppsala] (IRF), Laboratoire de Physique et Chimie de l'Environnement et de l'Espace (LPC2E), Observatoire des Sciences de l'Univers en région Centre (OSUC), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), Space Sciences Laboratory [Berkeley] (SSL), University of California [Berkeley] (UC Berkeley), University of California (UC)-University of California (UC), Centre National d'Études Spatiales [Toulouse] (CNES), Innovations for High Performance Microelectronics (IHP), Institut für Weltraumforschung = Space Research institute [Graz] (IWF), Osterreichische Akademie der Wissenschaften (ÖAW), Centre Hospitalier Régional Universitaire de Tours (CHRU Tours), Laboratoire de Biométrie et Biologie Evolutive - UMR 5558 (LBBE), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut National de Recherche en Informatique et en Automatique (Inria)-VetAgro Sup - Institut national d'enseignement supérieur et de recherche en alimentation, santé animale, sciences agronomiques et de l'environnement (VAS)-Centre National de la Recherche Scientifique (CNRS), Centre Hospitalier Lyon Sud [CHU - HCL] (CHLS), Hospices Civils de Lyon (HCL), ALTRAN (FRANCE), GeNeuro Innovation [Lyon], Hôpital Saint Eloi (CHRU Montpellier), Centre Hospitalier Régional Universitaire [Montpellier] (CHRU Montpellier), Institut des Neurosciences de Montpellier (INM), Institut National de la Santé et de la Recherche Médicale (INSERM)-Université de Montpellier (UM), Centre National de la Recherche Scientifique (CNRS), Université de Rennes (UR), Nexeya Conseil & Formation, Institute of Atmospheric Physics [Prague] (IAP), Czech Academy of Sciences [Prague] (CAS), Microbes, Intestin, Inflammation et Susceptibilité de l'Hôte (M2iSH), Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre de Recherche en Nutrition Humaine d'Auvergne (CRNH d'Auvergne)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Clermont Auvergne (UCA), Service de Médecine Interne [CHU Clermont-Ferrand], CHU Gabriel Montpied [Clermont-Ferrand], CHU Clermont-Ferrand-CHU Clermont-Ferrand, Royal Institute of Technology [Stockholm] (KTH ), Department of Physics and Astronomy [Calgary], University of Calgary, Space Research Institute of Austrian Academy of Sciences (IWF), Austrian Academy of Sciences (OeAW), NOAA National Marine Fisheries Service (NMFS), National Oceanic and Atmospheric Administration (NOAA), National Institute of Water and Atmospheric Research [Wellington] (NIWA), Department of Physics [Imperial College London], Imperial College London, Université Paris sciences et lettres (PSL), 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), Lunar and Planetary Laboratory [Tucson] (LPL), University of Arizona, University of Belgrade [Belgrade], Laboratoire des sciences de l'ingénieur, de l'informatique et de l'imagerie (ICube), École Nationale du Génie de l'Eau et de l'Environnement de Strasbourg (ENGEES)-Université de Strasbourg (UNISTRA)-Institut National des Sciences Appliquées - Strasbourg (INSA Strasbourg), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Institut National de Recherche en Informatique et en Automatique (Inria)-Les Hôpitaux Universitaires de Strasbourg (HUS)-Centre National de la Recherche Scientifique (CNRS)-Matériaux et Nanosciences Grand-Est (MNGE), Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS), Sorbonne Université (SU), International Centre for Radio Astronomy Research - Curtin University, Curtin University [Perth], Planning and Transport Research Centre (PATREC)-Planning and Transport Research Centre (PATREC), European Space Astronomy Centre (ESAC), Agence Spatiale Européenne = European Space Agency (ESA), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), University of California [Berkeley], University of California-University of California, Institut für Weltraumforschung [Graz] (IWF), CHU Saint-Eloi, Institut des Neurosciences de Montpellier - Déficits sensoriels et moteurs (INM), Université de Montpellier (UM)-Institut National de la Santé et de la Recherche Médicale (INSERM), 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), Institut National des Sciences Appliquées - Strasbourg (INSA Strasbourg), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-École Nationale du Génie de l'Eau et de l'Environnement de Strasbourg (ENGEES)-Réseau nanophotonique et optique, Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Matériaux et nanosciences d'Alsace (FMNGE), Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Strasbourg (UNISTRA)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), European Space Agency (ESA), and Centre Hospitalier Régional Universitaire de Tours (CHRU TOURS)

Subjects
Sun: general, 010504 meteorology & atmospheric sciences, Astronomy, Astrophysics, 01 natural sciences, 7. Clean energy, law.invention, Orbiter, Astronomi, astrofysik och kosmologi, law, 0103 physical sciences, Astronomy, Astrophysics and Cosmology, Aerospace engineering, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Physics, Sun: radio radiation, business.industry, Astrophysics::Instrumentation and Methods for Astrophysics, Sun, Astronomy and Astrophysics, solar wind, Space and Planetary Science, general, radio radiation, Physics::Space Physics, Astrophysics::Earth and Planetary Astrophysics, business, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

International audience; The Radio and Plasma Waves (RPW) instrument on the ESA Solar Orbiter mission is designed to measure in situ magnetic and electric fields and waves from the continuum up to several hundred kHz. The RPW also observes solar and heliospheric radio emissions up to 16 MHz. It was switched on and its antennae were successfully deployed two days after the launch of Solar Orbiter on February 10, 2020. Since then, the instrument has acquired enough data to make it possible to assess its performance and the electromagnetic disturbances it experiences. In this article, we assess its scientific performance and present the first RPW observations. In particular, we focus on a statistical analysis of the first observations of interplanetary dust by the instrument’s Thermal Noise Receiver. We also review the electro-magnetic disturbances that RPW suffers, especially those which potential users of the instrument data should be aware of before starting their research work.

Published
2021

4. Whistler waves observed by Solar Orbiter/RPW between 0.5 AU and 1 AU

Author

M. Kretzschmar, T. Chust, V. Krasnoselskikh, D. Graham, L. Colomban, M. Maksimovic, Yu. V. Khotyaintsev, J. Soucek, K. Steinvall, O. Santolík, G. Jannet, J.-Y. Brochot, O. Le Contel, A. Vecchio, X. Bonnin, S. D. Bale, C. Froment, A. Larosa, M. Bergerard-Timofeeva, P. Fergeau, E. Lorfevre, D. Plettemeier, M. Steller, Š. Štverák, P. Trávníček, A. Vaivads, T. S. Horbury, H. O’Brien, V. Evans, V. Angelini, C. J. Owen, P. Louarn, Space Sciences Laboratory [Berkeley] (SSL), University of California [Berkeley], University of California-University of California, Laboratoire de Physique et Chimie de l'Environnement et de l'Espace (LPC2E), Observatoire des Sciences de l'Univers en région Centre (OSUC), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), Centre National d'Études Spatiales [Toulouse] (CNES), 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), 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), Swedish Institute of Space Physics [Uppsala] (IRF), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Institute of Atmospheric Physics [Prague] (IAP), Czech Academy of Sciences [Prague] (CAS), Technische Universität Dresden = Dresden University of Technology (TU Dresden), Institut für Weltraumforschung [Graz] (IWF), Osterreichische Akademie der Wissenschaften (ÖAW), Astronomical Institute of the Czech Academy of Sciences (ASU / CAS), Department of Physics [Imperial College London], Imperial College London, Mullard Space Science Laboratory (MSSL), University College of London [London] (UCL), Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), University of California [Berkeley] (UC Berkeley), University of California (UC)-University of California (UC), Institut für Weltraumforschung = Space Research institute [Graz] (IWF), 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), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National d’Études Spatiales [Paris] (CNES)

Subjects
010504 meteorology & atmospheric sciences, Whistler, Astronomy, data analysis, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], FOS: Physical sciences, Astrophysics, 01 natural sciences, law.invention, methods, Orbiter, Fusion, plasma och rymdfysik, Physics - Space Physics, Astronomi, astrofysik och kosmologi, law, 0103 physical sciences, Astronomy, Astrophysics and Cosmology, waves, Sun: heliosphere, 010303 astronomy & astrophysics, Solar and Stellar Astrophysics (astro-ph.SR), 0105 earth and related environmental sciences, Physics, Computer Science::Information Retrieval, Sun, heliosphere, Astronomy and Astrophysics, Fusion, Plasma and Space Physics, methods: data analysis, Space Physics (physics.space-ph), Astrophysics - Solar and Stellar Astrophysics, solar wind, Space and Planetary Science, Physics::Space Physics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

The goal of our study is to detect and characterize the electromagnetic waves that can modify the electron distribution functions, with a special attention to whistler waves. We analyse in details the electric and magnetic field fluctuations observed by the Solar Orbiter spacecraft during its first orbit around the Sun between 0.5 and 1 AU. Using data of the Search Coil Magnetometer and electric antenna, both parts of the Radio and Plasma Waves (RPW) instrumental suite, we detect the electromagnetic waves with frequencies above 3 Hz and determine the statistical distribution of their amplitudes, frequencies, polarization and k-vector as a function of distance. We also discuss relevant instrumental issues regarding the phase between the electric and magnetic measurements and the effective length of the electric antenna. An overwhelming majority of the observed waves are right hand circularly polarized in the solar wind frame and identified as outward propagating and quasi parallel whistler waves. Their occurrence rate increases by a least a factor two from 1 AU to 0.5 AU. These results are consistent with the regulation of the heat flux by the whistler heat flux instability. Near 0.5 AU, whistler waves are found to be more field-aligned and to have smaller normalized frequency ($f/f_{ce}$), larger amplitude, and larger bandwidth than at 1 AU., accepted in A&A

Published
2021

5. The Solar Orbiter Solar Wind Analyser (SWA) suite

Author

C. Brockley-Blatt, Mark Phillips, G. Dirks, A. Malpus, J. Ford, Michael R. Collier, M. Hailey, C. Loeffler, G. Terrier, S. Myers, Iannis Dandouras, D. Rust, G. Capuano, L. M. Kistler, Gethyn R. Lewis, S. Clemens, R. Baruah, John A. Trevino, R. Ascolese, Jean-André Sauvaud, S. Persyn, K. Ruane, C. Urdiales, E. Penou, G. Davison, Timothy J. Stubbs, A. Barthe, J. Yardley, Vincent Génot, A. Lawrenson, R. Thibodeaux, B. Hancock, Glyn Collinson, Jason A. Gilbert, C. Anekallu, C. Jacquey, Robert F. Wimmer-Schweingruber, I. Čermák, S. Gradone, L. Přech, J. Coker, P. Louarn, V. de Giosa, Berend Winter, Timothy S. Horbury, W. Marty, M. Salatti, Daniel Verscharen, Jim M. Raines, P. Devoto, E. Edlund, C. Brysbaert, M. Johnson, J. Rubiella, T. Hunt, Frederic Allegrini, M. Ferris, Roberto Bruno, Matthieu Berthomier, M. Petiot, Christopher J. Owen, K. L. Arnett, A. Rousseau, D. Davies, V. Arciuli, P. Bland, Peter Wurz, J. W. Thomas, G. Mele, R. Calvanese, G. Watson, F. Monti, C. Bancroft, Dennis J. Chornay, P. Wheeler, Andrew Walsh, Jason L. Stange, K. Al Janabi, Dhiren Kataria, V. Fortunato, Keiichi Ogasawara, A. Spencer, Rossana DeMarco, Susan T. Lepri, C. Amoros, Milan Maksimovic, D. Heirtzler, Stefano Livi, N. André, Antoinette B. Galvin, Mark A. Popecki, Benoit Lavraud, A. Alapide, W. Gibson, Leonardo Amoruso, W. Lockhart, Raffaella D'Amicis, G. Willis, C. Mazelle, F. Marcucci, S. Rogacki, A. Pacros, A. P. Rouillard, F. Leblanc, K. Rees, J.-D. Techer, Javier Rodriguez-Pacheco, I. Fratter, Ali Varsani, I. Zouganelis, M. Orlandi, C. Garat, T. Taylor, Marco Castronuovo, C. Frost, G. Fruit, A. De Los Santos, A. Mayall, M. Reden, Andrew Fazakerley, R. Mathon, I. Phillips, A. Fedorov, T. Nguyen, H. Seran, M. Brysch, R. Darnley, Mark Stakhiv, S. Bordon, Institut de recherche en astrophysique et planétologie (IRAP), Centre National de la Recherche Scientifique (CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS), Mullard Space Science Laboratory (MSSL), University College of London [London] (UCL), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), 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), 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), Laboratoire d'études spatiales et d'instrumentation en astrophysique = Laboratory of Space Studies and Instrumentation in Astrophysics (LESIA), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), 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 d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)

Subjects
010504 meteorology & atmospheric sciences, Analyser, Astrophysics, 7. Clean energy, 01 natural sciences, law.invention, Orbiter, law, Sun: particle emission, 0103 physical sciences, Thermal, Astrophysics::Solar and Stellar Astrophysics, Aerospace engineering, Sun: heliosphere, 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Physics, Spacecraft, business.industry, instrumentation: detectors, [SDU.ASTR.SR]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Solar and Stellar Astrophysics [astro-ph.SR], Astronomy and Astrophysics, Plasma, plasmas, [SDU.ASTR.IM]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM], Solar wind, solar wind, Space and Planetary Science, [SDU]Sciences of the Universe [physics], Physics::Space Physics, Astrophysical plasma, Astrophysics::Earth and Planetary Astrophysics, business, Heliosphere
Abstract

The Solar Orbiter mission seeks to make connections between the physical processes occurring at the Sun or in the solar corona and the nature of the solar wind created by those processes which is subsequently observed at the spacecraft. The mission also targets physical processes occurring in the solar wind itself during its journey from its source to the spacecraft. To meet the specific mission science goals, Solar Orbiter will be equipped with both remote-sensing and in-situ instruments which will make unprecedented measurements of the solar atmosphere and the inner heliosphere. A crucial set of measurements will be provided by the Solar Wind Analyser (SWA) suite of instruments. This suite consists of an Electron Analyser System (SWA-EAS), a Proton and Alpha particle Sensor (SWA-PAS), and a Heavy Ion Sensor (SWA-HIS) which are jointly served by a central control and data processing unit (SWA-DPU). Together these sensors will measure and categorise the vast majority of thermal and suprathermal ions and electrons in the solar wind and determine the abundances and charge states of the heavy ion populations. The three sensors in the SWA suite are each based on the top hat electrostatic analyser concept, which has been deployed on numerous space plasma missions. The SWA-EAS uses two such heads, each of which have 360° azimuth acceptance angles and ±45° aperture deflection plates. Together these two sensors, which are mounted on the end of the boom, will cover a full sky field-of-view (FoV) (except for blockages by the spacecraft and its appendages) and measure the full 3D velocity distribution function (VDF) of solar wind electrons in the energy range of a few eV to ∼5 keV. The SWA-PAS instrument also uses an electrostatic analyser with a more confined FoV (−24° to +42° × ±22.5° around the expected solar wind arrival direction), which nevertheless is capable of measuring the full 3D VDF of the protons and alpha particles arriving at the instrument in the energy range from 200 eV/q to 20 keV/e. Finally, SWA-HIS measures the composition and 3D VDFs of heavy ions in the bulk solar wind as well as those of the major constituents in the suprathermal energy range and those of pick-up ions. The sensor resolves the full 3D VDFs of the prominent heavy ions at a resolution of 5 min in normal mode and 30 s in burst mode. Additionally, SWA-HIS measures 3D VDFs of alpha particles at a 4 s resolution in burst mode. Measurements are over a FoV of −33° to +66° × ±20° around the expected solar wind arrival direction and at energies up to 80 keV/e. The mass resolution (m/Δm) is > 5. This paper describes how the three SWA scientific sensors, as delivered to the spacecraft, meet or exceed the performance requirements originally set out to achieve the mission’s science goals. We describe the motivation and specific requirements for each of the three sensors within the SWA suite, their expected science results, their main characteristics, and their operation through the central SWA-DPU. We describe the combined data products that we expect to return from the suite and provide to the Solar Orbiter Archive for use in scientific analyses by members of the wider solar and heliospheric communities. These unique data products will help reveal the nature of the solar wind as a function of both heliocentric distance and solar latitude. Indeed, SWA-HIS measurements of solar wind composition will be the first such measurements made in the inner heliosphere. The SWA data are crucial to efforts to link the in situ measurements of the solar wind made at the spacecraft with remote observations of candidate source regions. This is a novel aspect of the mission which will lead to significant advances in our understanding of the mechanisms accelerating and heating the solar wind, driving eruptions and other transient phenomena on the Sun, and controlling the injection, acceleration, and transport of the energetic particles in the heliosphere.

Published
2020

6. In Situ Observations Connected to the Io Footprint Tail Aurora

Author

Denis Grodent, William S. Kurth, Scott Bolton, Fran Bagenal, Joachim Saur, Frederic Allegrini, Robert E. Ergun, Bertrand Bonfond, G. R. Gladstone, D. J. McComas, Stavros Kotsiaros, George Hospodarsky, R. J. Wilson, P. Louarn, Vincent Hue, Philip W Valek, Jamey Szalay, George Clark, Barry Mauk, John E. P. Connerney, Robert Ebert, Steven Levin, 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, Proton, Cyclotron, Io, Astrophysics, Electron, 01 natural sciences, Jovian, law.invention, Jupiter, Atmosphere, Geochemistry and Petrology, law, 0103 physical sciences, Earth and Planetary Sciences (miscellaneous), Transit (astronomy), 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Physics, aurora, Geophysics, [SDU]Sciences of the Universe [physics], Space and Planetary Science, Physics::Space Physics, Longitude
Abstract

The Juno spacecraft crossed flux tubes connected to the Io footprint tail at low Jovian altitudes on multiple occasions. The transits covered longitudinal separations of approximately 10 degrees to 120 degrees along the footprint tail. Juno's suite of magnetospheric instruments acquired detailed measurements of the Io footprint tail. Juno observed planetward electron energy fluxes of similar to 70mW/m(2) near the Io footprint and similar to 10mW/m(2) farther down the tail, along with correlated, intense electric and magnetic wave signatures, which also decreased down the tail. All observed electron distributions were broad in energy, suggesting a dominantly broadband acceleration process, and did not show any broad inverted-V structure that would be indicative of acceleration by a quasi-static, discrete, parallel potential. Observed waves were primarily below the proton cyclotron frequency, yet identification of a definitive wave mode is elusive. Beyond 40 degrees down the footprint tail, Juno observed depleted upward loss cones, suggesting that the broadband acceleration occurred at distances beyond Juno's transit distance of 1.3 to 1.7R(J). For all transits, Juno observed fine structure on scales of approximately tens of kilometers and confirmed independently with electron and wave measurements that a bifurcated tail can intermittently exist. Plain Language Summary The Juno spacecraft crossed regions magnetically connected to auroral structures associated with Jupiter's moon Io on multiple occasions. The transits covered longitudinal separations of approximately 10 degrees to 120 degrees along Io's auroral tail. Juno's suite of instruments acquired detailed measurements of these auroral structures. Juno directly observed the electrons that sustain these auroral features before they crash into the atmosphere and generate the brilliant aurora. The flux of these electrons decreased as Juno transited the tail farther from Io's longitude. While there are two main explanations for Io's auroral signatures, the nature of the observed electrons in this work favors one mechanism over the other. When Juno was far from Io's longitude, the observations suggest that the spacecraft was below the point at which the electrons are accelerated into the atmosphere. For all transits, Juno observed fine structure on scales of approximately tens of kilometers and confirmed that a bifurcated tail can intermittently exist.

Published
2018

7. Solar Orbiter observations of the Kelvin-Helmholtz waves in the solar wind

Author

Y. Yang, David Ruffolo, Julia E. Stawarz, N. Fargette, William H. Matthaeus, Andrei Fedorov, Vincent Génot, Helen O'Brien, P. Louarn, Christopher J. Owen, R. Kieokaew, A. P. Rouillard, Claire Foullon, S. Aizawa, Vincent Evans, V. Angelini, Emmanuel Penou, Timothy S. Horbury, Rui Pinto, Benoit Lavraud, 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), Harvard University [Cambridge], University of Warwick [Coventry], 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), Harvard University, Science and Technology Facilities Council (STFC), and The Royal Society

Subjects
astro-ph.SR, TANGENTIAL DISCONTINUITIES, 010504 meteorology & atmospheric sciences, INSTABILITY, MAGNETOPAUSE, SURFACE-WAVES, Astrophysics, Astronomy & Astrophysics, magnetohydrodynamics (MHD), 01 natural sciences, methods, law.invention, Orbiter, symbols.namesake, law, physics.plasm-ph, RECONNECTION, 0201 Astronomical and Space Sciences, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, observational, Sun: heliosphere, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Physics, Science & Technology, PLASMA, Computer Science::Information Retrieval, Sun, heliosphere, Astronomy, Astronomy and Astrophysics, MAGNETIC SHEAR, CURRENT SHEETS, plasmas, Solar wind, solar wind, physics.space-ph, instabilities, 13. Climate action, Space and Planetary Science, Helmholtz free energy, Physical Sciences, DIRECTIONAL DISCONTINUITIES, Physics::Space Physics, symbols, TURBULENCE, methods: observational, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

Context.The Kelvin-HeImholtz (KH) instability is a nonlinear shear-driven instability that develops at the interface between shear flows in plasmas. KH waves have been inferred in various astrophysical plasmas, and have been observed in situ at the magnetospheric boundaries of solar-system planets and through remote sensing at the boundaries of coronal mass ejections.Aims.KH waves are also expected to develop at flow shear interfaces in the solar wind. While they were hypothesized to play an important role in the mixing of plasmas and in triggering solar wind fluctuations, their direct and unambiguous observation in the solar wind was still lacking.Methods.We report in situ observations of quasi-periodic magnetic and velocity field variations plausibly associated with KH waves using Solar Orbiter during its cruise phase. They are found in a shear layer in the slow solar wind in the close vicinity of the heliospheric current sheet. An analysis was performed to derive the local configuration of the waves. A 2D magnetohydrodynamics simulation was also set up with approximate empirical values to test the stability of the shear layer. In addition, magnetic spectra of the event were analyzed.Results.We find that the observed conditions satisfy the KH instability onset criterion from the linear theory analysis, and its development is further confirmed by the simulation. The current sheet geometry analyses are found to be consistent with KH wave development, albeit with some limitations likely owing to the complex 3D nature of the event and solar wind propagation. Additionally, we report observations of an ion jet consistent with magnetic reconnection at a compressed current sheet within the KH wave interval. The KH activity is found to excite magnetic and velocity fluctuations with power law scalings that approximately followk−5/3andk−2.8in the inertial and dissipation ranges, respectively. Finally, we discuss reasons for the lack of in situ KH wave detection in past data.Conclusions.These observations provide robust evidence of KH wave development in the solar wind. This sheds new light on the process of shear-driven turbulence as mediated by the KH waves with implications for the driving of solar wind fluctuations.

Published
2021

8. Multi-spacecraft study of the solar wind at solar minimum: Dependence on latitude and transient outflows

Author

Emma E. Davies, Stuart D. Bale, Julia E. Stawarz, Daniel Heyner, V. Angelini, T. Woolley, L. D. Woodham, Matt J. Owens, Timothy S. Horbury, Vincent Evans, Lorenzo Matteini, P. Louarn, Ingo Richter, Jonathan Eastwood, R. Laker, Christopher J. Owen, A. Fedorov, Helen O'Brien, Science and Technology Facilities Council (STFC), Imperial College London, 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, Astrophysics, Space weather, 01 natural sciences, Physics - Space Physics, MAGNETIC RECONNECTION, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Physics::Atmospheric and Oceanic Physics, SOURCE-SURFACE, Physics, COROTATING INTERACTION REGIONS, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], PLASMA, Sun, heliosphere, CORONAL MASS EJECTIONS, Solar wind, Astrophysics - Solar and Stellar Astrophysics, solar wind, physics.space-ph, Physical Sciences, Physics::Space Physics, Astrophysics::Earth and Planetary Astrophysics, coronal mass ejections (CMEs), Solar minimum, astro-ph.SR, Sun: coronal mass ejections (CMEs), FOS: Physical sciences, Context (language use), Astronomy & Astrophysics, Latitude, INTERPLANETARY, 0201 Astronomical and Space Sciences, 0103 physical sciences, Sun: heliosphere, Solar and Stellar Astrophysics (astro-ph.SR), 0105 earth and related environmental sciences, Science & Technology, Spacecraft, business.industry, Astronomy and Astrophysics, Geophysics, Space Physics (physics.space-ph), MODEL, [SDU]Sciences of the Universe [physics], 13. Climate action, Space and Planetary Science, HELIOSPHERIC CURRENT SHEET, STREAM, AU, Heliospheric current sheet, business, Heliosphere
Abstract

The recent launches of Parker Solar Probe (PSP), Solar Orbiter (SO) and BepiColombo, along with several older spacecraft, have provided the opportunity to study the solar wind at multiple latitudes and distances from the Sun simultaneously. We take advantage of this unique spacecraft constellation, along with low solar activity across two solar rotations between May and July 2020, to investigate how the solar wind structure, including the Heliospheric Current Sheet (HCS), varies with latitude. We visualise the sector structure of the inner heliosphere by ballistically mapping the polarity and solar wind speed from several spacecraft onto the Sun's source surface. We then assess the HCS morphology and orientation with the in situ data and compare with a predicted HCS shape. We resolve ripples in the HCS on scales of a few degrees in longitude and latitude, finding that the local orientation of sector boundaries were broadly consistent with the shape of the HCS but were steepened with respect to a modelled HCS at the Sun. We investigate how several CIRs varied with latitude, finding evidence for the compression region affecting slow solar wind outside the latitude extent of the faster stream. We also identified several transient structures associated with HCS crossings, and speculate that one such transient may have disrupted the local HCS orientation up to five days after its passage. We have shown that the solar wind structure varies significantly with latitude, with this constellation providing context for solar wind measurements that would not be possible with a single spacecraft. These measurements provide an accurate representation of the solar wind within $\pm 10^{\circ}$ latitude, which could be used as a more rigorous constraint on solar wind models and space weather predictions. In the future, this range of latitudes will increase as SO's orbit becomes more inclined., Comment: Accepted version

Published
2021

9. Plasma measurements in the Jovian polar region with Juno/JADE

Author

John E. P. Connerney, Chris Paranicas, Steven Levin, D. J. Gershman, Michelle F. Thomsen, R. J. Wilson, M. Reno, Fran Bagenal, S. Weidner, David J. McComas, Barry Mauk, Robert Ebert, William S. Kurth, L. P. Dougherty, P. Louarn, Philip W Valek, D. A. Ranquist, Jamey Szalay, George Clark, Frederic Allegrini, and Scott Bolton

Subjects
Physics, education.field_of_study, 010504 meteorology & atmospheric sciences, Population, Plasma sheet, Astronomy, Magnetosphere, Torus, Plasma, 01 natural sciences, Jovian, Jupiter, Geophysics, Physics::Plasma Physics, Physics::Space Physics, 0103 physical sciences, General Earth and Planetary Sciences, Polar, Astrophysics::Earth and Planetary Astrophysics, education, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences
Abstract

Jupiter's main auroral oval provides a window into the complex magnetospheric dynamics of the jovian system. The Juno spacecraft entered orbit about Jupiter on 5 July 2016 and carries onboard the Auroral Distributions Experiment (JADE) that can directly sample the auroral plasma structures. Here, we identify five distinct regimes in the JADE data based on composition/energy boundaries and magnetic field mappings, which exhibit considerable symmetry between the northern and southern passes. These intervals correspond to periods when Juno was connected to the Io torus, inner plasma sheet, middle plasma sheet, outer plasma sheet, and the polar region. When connected to the torus and inner plasma sheet, the heavy ions are consistent with a corotating pickup population. For Juno's first perijove, we do not find evidence for a broad auroral acceleration region at Jupiter's main auroral oval for energies below 100 keV.

Published
2017

10. Plasma environment at the dawn flank of Jupiter's magnetosphere: Juno arrives at Jupiter

Author

Philip W Valek, David J. McComas, Scott Bolton, William S. Kurth, Jamey Szalay, M. Reno, S. Weidner, P. Louarn, Michelle F. Thomsen, John E. P. Connerney, Barry Mauk, R. J. Wilson, Fran Bagenal, Robert Ebert, and Frederic Allegrini

Subjects
Physics, 010504 meteorology & atmospheric sciences, Astronomy, Magnetosphere, Plasma, Bow shocks in astrophysics, 01 natural sciences, JADE (particle detector), Jovian, Jupiter, Geophysics, 0103 physical sciences, General Earth and Planetary Sciences, Magnetopause, Ionosphere, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences
Abstract

This study examines the first observations from the Jovian Auroral Distributions Experiment (JADE) as the Juno spacecraft arrived at Jupiter. JADE observations show that Juno crossed the bow shock at 08:16 UT on 2016 day of year (DOY) 176 and magnetopause at 21:20 on DOY 177, with additional magnetopause encounters until 23:39 on DOY 181. JADE made the first detailed observations of the plasma environment just inside the dawn flank of the magnetopause. We find subcorotational ions and variable electron beaming, with multiple flux tubes of varying plasma properties. Ion composition shows a dearth of heavy ions; protons dominate the plasma, with only intermittent, low fluxes of O+/S++, along with traces of O++ and S+++. We also find very little H3+ or He+, which are expected for an ionospheric plasma source. A few heavy ion bursts occur when the radial field nears reversal, but many other such reversals are not accompanied by heavy ions.

Published
2017

11. Generation of the Jovian hectometric radiation: First lessons from Juno

Author

Frederic Allegrini, P. Louarn, R. J. Wilson, N. André, J. L. Zink, William S. Kurth, Scott Bolton, John E. P. Connerney, Steven Levin, S. Weidner, Jamey Szalay, Robert Ebert, Masafumi Imai, David J. McComas, Philip W Valek, Fran Bagenal, 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, 010504 meteorology & atmospheric sciences, Magnetosphere, Astronomy, Auroral kilometric radiation, 01 natural sciences, Instability, radio waves, Jovian, law.invention, Jupiter, Geophysics, [SDU]Sciences of the Universe [physics], law, Physics::Space Physics, 0103 physical sciences, magnetosphere, General Earth and Planetary Sciences, Pitch angle, Maser, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Radio wave
Abstract

International audience; Using Juno plasma and wave and magnetic observations (JADE and Waves and MAG instruments), the generation mechanism of the Jovian hectometric radio emission is analyzed. It is shown that suitable conditions for the cyclotron maser instability (CMI) are observed in the regions of the radio sources. Pronounced loss cone in the electron distributions are likely the source of free energy for the instability. The theory reveals that sufficient growth rates are obtained from the distribution functions that are measured by the JADE-Electron instrument. The CMI would be driven by upgoing electron populations at 5-10 keV and 10-30° pitch angle, the amplified waves propagating at 82°-87° from the B field, a fraction of a percent above the gyrofrequency. Typical e-folding times of 10-4 s are obtained, leading to an amplification path of 1000 km. Overall, this scenario for generation of the Jovian hectometric waves differs significantly from the case of the auroral kilometric radiation at Earth.

Published
2017

12. Accelerated flows at Jupiter's magnetopause: Evidence for magnetic reconnection along the dawn flank

Author

M. Reno, Michelle F. Thomsen, Jamey Szalay, George Clark, Gina A. DiBraccio, P. Louarn, D. J. Gershman, D. J. McComas, Scott Bolton, Frederic Allegrini, S. Weidner, Steven Levin, Philip W Valek, William S. Kurth, Barry Mauk, Robert Ebert, John E. P. Connerney, R. J. Wilson, and Fran Bagenal

Subjects
Physics, 010504 meteorology & atmospheric sciences, Magnetosphere, Magnetic reconnection, Geophysics, Astrophysics, 01 natural sciences, Jovian, Jupiter, Magnetosheath, Magnetosphere of Saturn, Physics::Space Physics, 0103 physical sciences, General Earth and Planetary Sciences, Magnetopause, Astrophysics::Earth and Planetary Astrophysics, Magnetosphere of Jupiter, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences
Abstract

We report on plasma and magnetic field observations from Juno's Jovian Auroral Distributions Experiment and Magnetic Field Investigation at eighteen magnetopause crossings when the spacecraft was located at ~6 h magnetic local time and 73 – 114 jovian radii from Jupiter. Several crossings showed evidence of plasma energization, accelerated ion flows, and large magnetic shear angles, each representing a signature of magnetic reconnection. These signatures were observed for times when the magnetosphere was in both compressed and expanded states. We compared the flow change magnitudes to a simplified Walen relation and found ~60% of the events to be 110% or less of the predicted values. Close examination of two magnetopause encounters revealed characteristics of a rotational discontinuity and an open magnetopause. These observations provide compelling evidence that magnetic reconnection can occur at Jupiter's dawn magnetopause and should be incorporated into theories of solar wind coupling and outer magnetosphere dynamics at Jupiter.

Published
2017

13. Jovian High‐Latitude Ionospheric Ions: Juno In Situ Observations

Author

John E. P. Connerney, Steve Levin, Michelle F. Thomsen, P. Louarn, Robert Ebert, T. K. Kim, Jamey Szalay, R. J. Wilson, P. W. Valek, Frederic Allegrini, Fran Bagenal, D. J. McComas, Scott Bolton, Southwest Research Institute [San Antonio] (SwRI), The University of Texas at San Antonio (UTSA), Laboratory for Atmospheric and Space Physics [Boulder] (LASP), University of Colorado [Boulder], NASA Goddard Space Flight Center (GSFC), Space Systems Research Corporation (SSRC), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), 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), Princeton University, Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), and Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)

Subjects
In situ, Physics, 010504 meteorology & atmospheric sciences, Astronomy, 7. Clean energy, 01 natural sciences, Jovian, Ion, Physics::Geophysics, Jupiter, Geophysics, 13. Climate action, Physics::Plasma Physics, [SDU]Sciences of the Universe [physics], High latitude, 0103 physical sciences, Physics::Space Physics, General Earth and Planetary Sciences, Astrophysics::Earth and Planetary Astrophysics, Ionosphere, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences
Abstract

International audience; The lowaltitude, highvelocity trajectory of the Juno spacecraft enables the Jovian Auroral Distributions Experiment to make the rst in situ observations of the highlatitude ionospheric plasma. Ions are observed to energies below 1 eV. The highlatitude ionospheric ions are observed simultaneously with a loss cone in the magnetospheric ions, suggesting precipitating magnetospheric ions contribute to the heating of the upper ionosphere, raising the scale height, and pushing ionospheric ions to altitudes of 0.5 RJ above the planet where they are observed by Jovian Auroral Distributions Experiment. The source of the magnetospheric ions is tied to the Io torus and plasma sheet, indicated by the cutoff seen in both the magnetospheric and ionospheric plasma at the Io Mshells. Equatorward of the Io Mshell boundary, the ionospheric ions are not observed, indicating a drop in the scale height of the ionospheric ions at those latitudes.

Published
2019

14. Comparing Electron Energetics and UV Brightness in Jupiter's Northern Polar Region During Juno Perijove 5

Author

Fran Bagenal, G. R. Gladstone, Steven Levin, Barry Mauk, Thomas K. Greathouse, Vincent Hue, P. Louarn, R. J. Wilson, Michelle F. Thomsen, Jamey Szalay, John E. P. Connerney, Robert Ebert, Masafumi Imai, P. W. Valek, George Clark, William S. Kurth, Frederic Allegrini, David J. McComas, Scott Bolton, Chris Paranicas, Southwest Research Institute [San Antonio] (SwRI), Laboratory for Atmospheric and Space Physics [Boulder] (LASP), University of Colorado [Boulder], NASA Goddard Space Flight Center (GSFC), Department of Nuclear Engineering, Kyoto University, ECLIPSE 2015, Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), University of Iowa [Iowa City], Institut de recherche en astrophysique et planétologie (IRAP), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-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), Johns Hopkins University Applied Physics Laboratory [Laurel, MD] (APL), Princeton University, Institut de médecine moléculaire de Rangueil (I2MR), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées- Institut Fédératif de Recherche Bio-médicale Institution (IFR150)-Institut National de la Santé et de la Recherche Médicale (INSERM), School of Social and Community Medicine [Bristol], University of Bristol [Bristol], Louarn, Philippe, Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Université de Toulouse (UT)-Université de Toulouse (UT)- Institut Fédératif de Recherche Bio-médicale Institution (IFR150)-Institut National de la Santé et de la Recherche Médicale (INSERM), Kyoto University [Kyoto], 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), and Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-IFR150-Institut National de la Santé et de la Recherche Médicale (INSERM)

Subjects
Juno, Brightness, Jupiter's aurora, 010504 meteorology & atmospheric sciences, polar auroral region, Astrophysics::High Energy Astrophysical Phenomena, Energy flux, Electron, Astrophysics, [SDU.ASTR] Sciences of the Universe [physics]/Astrophysics [astro-ph], 7. Clean energy, 01 natural sciences, Jupiter, [SDU] Sciences of the Universe [physics], Planetary Sciences: Solar System Objects, Flux (metallurgy), Altitude, Aurorae, 0103 physical sciences, Research Letter, Magnetospheric Physics, 010303 astronomy & astrophysics, Planetary Sciences: Fluid Planets, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Physics, electron energy flux, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Energetics, Planetary Magnetospheres, Energetic Particles: Precipitating, Polar Regions, Research Letters, polar UV emissions, Geophysics, Magnetospheres, precipitating electrons, 13. Climate action, [SDU]Sciences of the Universe [physics], Physics::Space Physics, General Earth and Planetary Sciences, Polar, Space Sciences
Abstract

We compare electron and UV observations mapping to the same location in Jupiter's northern polar region, poleward of the main aurora, during Juno perijove 5. Simultaneous peaks in UV brightness and electron energy flux are identified when observations map to the same location at the same time. The downward energy flux during these simultaneous observations was not sufficient to generate the observed UV brightness; the upward energy flux was. We propose that the primary acceleration region is below Juno's altitude, from which the more intense upward electrons originate. For the complete interval, the UV brightness peaked at ~240 kilorayleigh (kR); the downward and upward energy fluxes peaked at 60 and 700 mW/m2, respectively. Increased downward energy fluxes are associated with increased contributions from tens of keV electrons. These observations provide evidence that bidirectional electron beams with broad energy distributions can produce tens to hundreds of kilorayleigh polar UV emissions., Key Points Simultaneous peaks are observed in electron energy flux and UV brightness when they map to same location in Jupiter's polar region at the same timeUpward greater than downward electron energy fluxes are observed, suggesting that primary acceleration region may be below ~1.5 jovian radiiDownward energy fluxes able to produce tens to hundreds of kilorayleigh polar UV emissions are identified; increases in energy flux due to tens of keV electrons

Published
2019

15. Observation of Electron Conics by Juno: Implications for Radio Generation and Acceleration Processes

Author

Jamey Szalay, Scott Bolton, Frederic Allegrini, Robert Ebert, Philip W Valek, David J. McComas, Steven Levin, Fran Bagenal, William S. Kurth, R. J. Wilson, N. André, Masafumi Imai, P. Louarn, Centre d'étude spatiale des rayonnements (CESR), Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées, Southwest Research Institute [San Antonio] (SwRI), Princeton University, University of Iowa [Iowa City], Laboratory for Atmospheric and Space Physics [Boulder] (LASP), University of Colorado [Boulder], Vecteurs - Infections tropicales et méditerranéennes (VITROME), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut de Recherche Biomédicale des Armées (IRBA), 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 Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut de Recherche Biomédicale des Armées [Brétigny-sur-Orge] (IRBA)

Subjects
Physics, 010504 meteorology & atmospheric sciences, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Electron, 01 natural sciences, Computational physics, Acceleration, Geophysics, Conic section, 0103 physical sciences, General Earth and Planetary Sciences, 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences
Abstract

International audience

Published
2018

16. Observation of energy-time dispersed ion structures in the magnetosheath by CLUSTER: possible signatures of transient acceleration processes at shock

Author

Karim Meziane, Iannis Dandouras, Malcolm Dunlop, George K. Parks, J. M. Bosqued, P. Louarn, André Balogh, Ermanno Amata, Urs Mall, H. Rème, J. A. Sauvaud, L. M. Kistler, E. Budnik, P. W. Daly, Centre d'étude spatiale des rayonnements (CESR), Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées, University of California, MPAE, STFC Rutherford Appleton Laboratory (RAL), Science and Technology Facilities Council (STFC), Blackett Laboratory, Imperial College London, University of New Hamsphire, ISFI, 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)

Subjects
Shock wave, Atmospheric Science, 010504 meteorology & atmospheric sciences, Astrophysics::High Energy Astrophysical Phenomena, Magnetosphere, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, 01 natural sciences, Relativistic particle, Magnetosheath, 0103 physical sciences, Earth and Planetary Sciences (miscellaneous), lcsh:Science, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Physics, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, lcsh:QC801-809, Geology, Astronomy and Astrophysics, Fermi acceleration, lcsh:QC1-999, Computational physics, Shock (mechanics), Particle acceleration, lcsh:Geophysics. Cosmic physics, Solar wind, Classical mechanics, Space and Planetary Science, Physics::Space Physics, lcsh:Q, lcsh:Physics
Abstract

We analyse energy-time dispersed ion signatures that have been observed by CLUSTER in the dayside magnetosheath. These events are characterized by sudden increases in the ion flux at energies larger than 10 keV. The high energy ions (30 keV) are first detected, with the transition to the low energy ions (5 keV) lasting about 100 s. These injections are often associated with transient plasma structures of a few minutes in duration, characterized by a hotter, less dense plasma and a diverted flow velocity, thus presenting similarities with "hot flow anomalies". They also involve modifications of the magnetic field direction, suggesting that the shock interacts with a solar wind discontinuity at the time of the event. The injections can originate from the magnetosphere or the shock region. Studying in detail a particular event, we discuss this last hypothesis. We show that the observed energy/time dispersion can be explained by combining a time-of-flight effect with a drift of the source of energetic particles along the shock. We propose that the acceleration results from a Fermi process linked to the interaction of the discontinuity with a quasi-perpendicular shock. This model explains the observed pitch-angle selection of the accelerated particles. The Fermi process acting on the beam of ions reflected from the shock appears to be sufficiently efficient to accelerate over short time scales (less than 30 s) particles at energies above 30 keV.Key words. Magnetospheric physics (solar-wind-magnetosphere interaction; magnetosheath) – Space plasma physics (shock waves)

Published
2018

17. A new view of Jupiter's auroral radio spectrum

Author

Fran Bagenal, Steven Levin, George Hospodarsky, Scott Bolton, Frederic Allegrini, P. Louarn, Philip W Valek, Masafumi Imai, P. Zarka, Alberto Adriani, David J. McComas, Barry Mauk, G. R. Gladstone, William S. Kurth, John E. P. Connerney, D. A. Gurnett, Department of Physics and Astronomy [Iowa City], University of Iowa [Iowa City], 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), Southwest Research Institute [San Antonio] (SwRI), NASA Goddard Space Flight Center (GSFC), Johns Hopkins University Applied Physics Laboratory [Laurel, MD] (APL), Jet Propulsion Laboratory (JPL), California Institute of Technology (CALTECH)-NASA, Istituto di Astrofisica e Planetologia Spaziali - INAF (IAPS), Istituto Nazionale di Astrofisica (INAF), Laboratory for Atmospheric and Space Physics [Boulder] (LASP), University of Colorado [Boulder], Department of Astrophysical Sciences [Princeton], Princeton University, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), 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 NASA-California Institute of Technology (CALTECH)

Subjects
010504 meteorology & atmospheric sciences, Astrophysics::High Energy Astrophysical Phenomena, Cyclotron, Magnetosphere, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Radio spectrum, Orbital inclination, law.invention, Jupiter, law, 0103 physical sciences, Broadband, Maser, 010303 astronomy & astrophysics, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Physics, [PHYS]Physics [physics], Waves in plasmas, Astronomy, Geophysics, [SDU]Sciences of the Universe [physics], Physics::Space Physics, General Earth and Planetary Sciences, Astrophysics::Earth and Planetary Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

Juno's first perijove science observations were carried out on 27 August 2016. The 90° orbit inclination and 4163 km periapsis altitude provide the first opportunity to explore Jupiter's polar magnetosphere. A radio and plasma wave instrument on Juno called Waves provided a new view of Jupiter's auroral radio emissions from near 10 kHz to ~30 MHz. This frequency range covers the classically named decametric, hectometric, and broadband kilometric radio emissions, and Juno observations showed much of this entire spectrum to consist of V-shaped emissions in frequency-time space with intensified vertices located very close to the electron cyclotron frequency. The proximity of the radio emissions to the cyclotron frequency along with loss cone features in the energetic electron distribution strongly suggests that Juno passed very close to, if not through, one or more of the cyclotron maser instability sources thought to be responsible for Jupiter's auroral radio emissions.

Published
2017

18. Spatial Distribution and Properties of 0.1-100 keV Electrons in Jupiter's Polar Auroral Region

Author

Vincent Hue, Joachim Saur, D. J. McComas, George Clark, William S. Kurth, G. R. Gladstone, Michelle F. Thomsen, Robert Ebert, Jamey Szalay, M. Reno, Steve Levin, P. Louarn, Fran Bagenal, Frederic Allegrini, Chris Paranicas, S. Weidner, Scott Bolton, John E. P. Connerney, R. J. Wilson, Barry Mauk, Philip W Valek, 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
Juno, 010504 meteorology & atmospheric sciences, Energy flux, Astrophysics, Electron, Radiation, medicine.disease_cause, 01 natural sciences, Jovian, Electric field, 0103 physical sciences, medicine, polar aurora, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Physics, electron acceleration, parallel electric fields, Astronomy, polar magnetosphere, Magnetic field, Geophysics, [SDU]Sciences of the Universe [physics], Jupiter, Physics::Space Physics, General Earth and Planetary Sciences, Polar, Ultraviolet
Abstract

We present observations of 0.1-100 keV electrons from Juno's Jovian Auroral Distributions Experiment Electron instrument over Jupiter's polar auroral region for periods around four Juno perijoves (PJ1, PJ3, PJ4, and PJ5). The observations reveal regions containing magnetic field aligned beams of bidirectional electrons having broad energy distributions interspersed between beams of upward electrons with narrow, peaked energy distributions, regions void of these electrons, and regions dominated by penetrating radiation. The electrons show evidence of acceleration via parallel electric fields (inverted-V structures) and via stochastic processes (bidirectional distributions). The inverted-V structures shown here were observed from similar to 1.4 to 2.9 R-J and had spatial scales of hundreds to thousands of kilometers along Juno's trajectory. The upward electron energy flux was typically greater than the downward flux, the latter ranging between similar to 0.01 and 5 mW m(-2) for two cases shown here which we estimate could produce similar to 0.1-50 kR of ultraviolet emission. Plain Language Summary We report on observations of 0.1 - 100 kilo-electron volt electrons from the Jovian Auroral Distributions Experiment Electron instrument (JADE-E) on Juno over the region where Jupiter's ultraviolet (UV) polar aurora is produced. The observations show electrons moving both towards and away from Jupiter. These electrons show both broad and narrow energy distributions, suggesting the presence of at least two different acceleration mechanisms. Regions void of these electrons and regions dominated by penetrating radiation were also identified. The energy flux of the electrons moving towards Jupiter was sufficient to produce the weaker UV polar auroral emissions observed at Jupiter but a different source of electrons, likely with higher energies, is required to account for the brighter emissions.

Published
2017

19. Electron beams and loss cones in the auroral regions of Jupiter

Author

R. J. Wilson, Barry Mauk, John E. P. Connerney, D. A. Ranquist, Robert Ebert, T. K. Kim, S. Weidner, Fran Bagenal, M. Reno, Scott Bolton, Steven Levin, Michelle F. Thomsen, P. Louarn, David J. McComas, William S. Kurth, J. L. Zink, George Clark, Phil Valek, Frederic Allegrini, Craig J. Pollock, Jamey Szalay, 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, 010504 meteorology & atmospheric sciences, Jovian electrons, Astronomy, Electron, 01 natural sciences, Power law, JADE (particle detector), Jovian, Spectral line, Latitude, electron beams, Jupiter, auroral electrons, Acceleration, Geophysics, [SDU]Sciences of the Universe [physics], 0103 physical sciences, Physics::Space Physics, General Earth and Planetary Sciences, Astrophysics::Earth and Planetary Astrophysics, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences
Abstract

International audience; We report on the first observations of 100 eV to 100 keV electrons over the auroral regions of Jupiter by the Jovian Auroral Distributions Experiment (JADE) on board the Juno mission. The focus is on the regions that were magnetically connected to the main auroral oval. Amongst the most remarkable features, JADE observed electron beams, mostly upward going but also some downward going in the south, at latitudes from 69° to 72° and -66° to -70° corresponding to M shells ("M" for magnetic) from 18 to 54 and 28 to 61, respectively. The beams were replaced by upward loss cones at lower latitudes. There was no evidence of strongly accelerated downward electrons analogous to the auroral "inverted Vs" at Earth. Rather, the presence of upward loss cones suggests a diffuse aurora process. The energy spectra resemble tails of distributions or power laws (suggestive of a stochastic acceleration process) but can also have some clear enhancements or even peaks generally between 1 and 10 keV. Electron intensities change on timescales of a second or less at times implying that auroral structures can be of the order of a few tens of kilometers.

Published
2017

20. The Jovian Auroral Distributions Experiment (JADE) on the Juno Mission to Jupiter

Author

N. Alexander, d. T. Everett, Tiffany J. Finley, B. Rodriguez, George Clark, J. Johnson, R.D. Hill, M. Maple, Fran Bagenal, P. Louarn, C. Loeffler, Daniel Santos-Costa, A. Gribanova, M. Reno, David J. McComas, Robert Wilson, J. Dickinson, F. J. Crary, Phil Valek, W. Mills, Craig J. Pollock, D. White, Frederic Allegrini, P. Wilson, Chip R. Beebe, A. De Los Santos, M. I. Desai, Jean-Noël Rouzaud, C. Kofoed, S. Weidner, and D. Demkee

Subjects
Physics, 010504 meteorology & atmospheric sciences, Spacecraft, business.industry, Magnetosphere, Astronomy, Astronomy and Astrophysics, Field of view, 01 natural sciences, JADE (particle detector), Jovian, Jupiter, Planetary science, Exploration of Jupiter, Space and Planetary Science, 0103 physical sciences, business, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences
Abstract

The Jovian Auroral Distributions Experiment (JADE) on Juno provides the critical in situ measurements of electrons and ions needed to understand the plasma energy particles and processes that fill the Jovian magnetosphere and ultimately produce its strong aurora. JADE is an instrument suite that includes three essentially identical electron sensors (JADE-Es), a single ion sensor (JADE-I), and a highly capable Electronics Box (EBox) that resides in the Juno Radiation Vault and provides all necessary control, low and high voltages, and computing support for the four sensors. The three JADE-Es are arrayed 120∘ apart around the Juno spacecraft to measure complete electron distributions from ∼0.1 to 100 keV and provide detailed electron pitch-angle distributions at a 1 s cadence, independent of spacecraft spin phase. JADE-I measures ions from ∼5 eV to ∼50 keV over an instantaneous field of view of 270∘×90∘ in 4 s and makes observations over all directions in space each 30 s rotation of the Juno spacecraft. JADE-I also provides ion composition measurements from 1 to 50 amu with m/Δm∼2.5, which is sufficient to separate the heavy and light ions, as well as O+ vs S+, in the Jovian magnetosphere. All four sensors were extensively tested and calibrated in specialized facilities, ensuring excellent on-orbit observations at Jupiter. This paper documents the JADE design, construction, calibration, and planned science operations, data processing, and data products. Finally, the Appendix describes the Southwest Research Institute [SwRI] electron calibration facility, which was developed and used for all JADE-E calibrations. Collectively, JADE provides remarkably broad and detailed measurements of the Jovian auroral region and magnetospheric plasmas, which will surely revolutionize our understanding of these important and complex regions.

Published
2013

21. Electrostatic drift instability in a magnetotail configuration: The role of bouncing electrons

Author

G. Fruit, A. Tur, and P. Louarn

Subjects
Physics, 010504 meteorology & atmospheric sciences, Vlasov equation, Plasma, Electron, Condensed Matter Physics, 01 natural sciences, Instability, 010305 fluids & plasmas, Magnetic field, Distribution function, Physics::Plasma Physics, Dispersion relation, 0103 physical sciences, Atomic physics, Magnetosphere particle motion, 0105 earth and related environmental sciences
Abstract

To understand the possible destabilization of two-dimensional current sheets, a kinetic model is proposed to describe the resonant interaction between electrostatic modes and trapped electrons that bounce within the sheet. This work follows the initial investigation by Tur, Louarn, and Yanovsky [Phys. Plasmas 17, 102905 (2010)] and Fruit, Louarn, and Tur [Phys. Plasmas 20, 022113 (2013)] that is revised and extended. Using a quasi-dipolar equilibrium state, the linearized gyro-kinetic Vlasov equation is solved for electrostatic fluctuations with a period of the order of the electron bounce period. Using an appropriated Fourier expansion of the particle motion along the magnetic field, the complete time integration of the non-local perturbed distribution functions is performed. The dispersion relation for electrostatic modes is then obtained through the quasineutrality condition. It is found that for a mildly stretched configuration ( L∼8), strongly unstable electrostatic modes may develop in the current s...

Published
2017

22. A study of the propagation of Alfvén waves in the auroral density cavities

Author

Vincent Génot, P. Louarn, D. Le Quéau, Centre d'étude spatiale des rayonnements (CESR), Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées, Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)

Subjects
Atmospheric Science, 010504 meteorology & atmospheric sciences, Wave propagation, Soil Science, Magnetosphere, Aquatic Science, Oceanography, 01 natural sciences, [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], Alfvén wave, Geochemistry and Petrology, Electric field, 0103 physical sciences, Earth and Planetary Sciences (miscellaneous), 14. Life underwater, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Earth-Surface Processes, Water Science and Technology, Physics, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Ecology, Paleontology, Forestry, Geophysics, Polarization (waves), Magnetic field, Computational physics, Particle acceleration, Amplitude, Space and Planetary Science, Physics::Space Physics, Magnetospheric Physics: Auroral phenomena
Abstract

From the Viking and, more recently, the FAST spacecraft observations, it is known that the auroral acceleration regions correspond to relatively small-scale density cavities (a few kilometers to a few tens of kilometers in a direction perpendicular to the magnetic field). In order to study how Alfven waves can contribute to the auroral acceleration, we analyze their propagation in the presence of the sharp density gradients that characterize the edges of these cavities. It is shown that an Alfven wave packet entering into the cavity quickly develops short perpendicular length scales in the region of density inhomogeneity. Transverse scales of the order of c/ω pe are reached after a propagation of a few tenths of second, which corresponds to ∼ 2000 km in the cavity. This contributes to the creation of significant parallel electric field in the region of density gradient. Its amplitude is enhanced by the formation, on the gradients, of strong space charges due to the ion polarization drift. As the auroral cavities are known to be strong current regions, the density gradients would thus be the sites of particularly powerful wave/particle energy transfer and consequently, if the incident flux of Alfven waves coming from the magnetosphere is high enough, of the strongest particle acceleration.

Published
1999

23. [Untitled]

Author

P. Louarn, J. M. Nappa, L. Friel, Wlodek Kofman, N. Cornilleau-Wehrlin, R. Manning, S. Perraut, P. Robert, C. de Villedary, D. Hubert, F. Wouters, Laurence Rezeau, Jean-Louis Pinçon, Y. de Conchy, C. Lacombe, A. Meyer, François Lefeuvre, S. Louis, Michel Parrot, A. Roux, B. Poirier, C. C. Harvey, and P. Chauveau

Subjects
Electromagnetic field, Physics, Spectrum analyzer, 010504 meteorology & atmospheric sciences, Field (physics), Dynamic range, Magnetometer, Acoustics, Astronomy and Astrophysics, 01 natural sciences, law.invention, Search coil, Solar wind, Nuclear magnetic resonance, Space and Planetary Science, law, 0103 physical sciences, Waveform, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences
Abstract

The Spatio-Temporal Analysis of Field Fluctuations (STAFF) experiment is one of five experiments which together comprise the Wave Experiment Consortium (WEC). STAFF consists of a three-axis search coil magnetometer to measure magnetic fluctuations at frequencies up to 4 kHz, and a spectrum analyser to calculate in near-real time aboard the spacecraft, the complete auto- and cross-spectral matrices using the three magnetic and two electric components of the electromagnetic field. The magnetic waveform at frequencies below either 10 Hz or 180 Hz is also transmitted. The sensitivity of the search coil is adapted to the phenomena theo be studied: the values 3 × 10-3 nT Hz-1/2 and 3 × 10-5 nT Hz-1/2 are achieved respectively at 1 Hz and 100 Hz. The dynamic range of the STAFF instruments is about 96 dB in both waveform and spectral power, so as to allow the study of waves near plasma boundaries. Scientific objectives of the STAFF investigations, particularly those requiring four point measurements, are discussed. Methods by which the wave data will be characterised are described with emphasis on those specific to four-point measurements, including the use of the Field Energy Distribution function.

Published
1997

24. Solar wind plasma interaction with solar probe plus spacecraft

Author

S. Guillemant, V. Génot, J.-C. Matéo-Vélez, R. Ergun, P. Louarn, 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), ONERA - The French Aerospace Lab [Châtillon], ONERA-Université Paris Saclay (COmUE), Laboratory for Atmospheric and Space Physics [Boulder] (LASP), University of Colorado [Boulder], Thèse CNES / Région Midi-Pyrénées, 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
spacecraft charging, Atmospheric Science, 010504 meteorology & atmospheric sciences, [PHYS.ASTR.EP]Physics [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], Electron, 01 natural sciences, 7. Clean energy, Secondary electrons, 010305 fluids & plasmas, Spacecraft charging, numerical simulations, Solar Probe Plus, 0103 physical sciences, Earth and Planetary Sciences (miscellaneous), lcsh:Science, 0105 earth and related environmental sciences, Physics, Spacecraft, business.industry, solar wind plasma, lcsh:QC801-809, Geology, Astronomy and Astrophysics, Plasma, Photoelectric effect, lcsh:QC1-999, Solar wind, lcsh:Geophysics. Cosmic physics, Space and Planetary Science, Physics::Space Physics, lcsh:Q, Particle-in-cell, Astrophysics::Earth and Planetary Astrophysics, Atomic physics, business, lcsh:Physics
Abstract

3-D PIC (Particle In Cell) simulations of spacecraft-plasma interactions in the solar wind context of the Solar Probe Plus mission are presented. The SPIS software is used to simulate a simplified probe in the near-Sun environment (at a distance of 0.044 AU or 9.5 RS from the Sun surface). We begin this study with a cross comparison of SPIS with another PIC code, aiming at providing the static potential structure surrounding a spacecraft in a high photoelectron environment. This paper presents then a sensitivity study using generic SPIS capabilities, investigating the role of some physical phenomena and numerical models. It confirms that in the near- sun environment, the Solar Probe Plus spacecraft would rather be negatively charged, despite the high yield of photoemission. This negative potential is explained through the dense sheath of photoelectrons and secondary electrons both emitted with low energies (2–3 eV). Due to this low energy of emission, these particles are not ejected at an infinite distance of the spacecraft and would rather surround it. As involved densities of photoelectrons can reach 106 cm−3 (compared to ambient ions and electrons densities of about 7 × 103 cm−3), those populations affect the surrounding plasma potential generating potential barriers for low energy electrons, leading to high recollection. This charging could interfere with the low energy (up to a few tens of eV) plasma sensors and particle detectors, by biasing the particle distribution functions measured by the instruments. Moreover, if the spacecraft charges to large negative potentials, the problem will be more severe as low energy electrons will not be seen at all. The importance of the modelling requirements in terms of precise prediction of spacecraft potential is also discussed.

Published
2012

25. Emission and propagation of Saturn kilometric radiation: Magnetoionic modes, beaming pattern, and polarization state

Author

Baptiste Cecconi, P. Louarn, D. J. Menietti, D. A. Gurnett, Robert L. Mutel, William S. Kurth, P. Schippers, Patrick Canu, L. Lamy, and P. Zarka

Subjects
Atmospheric Science, 010504 meteorology & atmospheric sciences, Plasma parameters, Soil Science, Magnetosphere, Auroral kilometric radiation, Aquatic Science, Oceanography, 7. Clean energy, 01 natural sciences, Geochemistry and Petrology, 0103 physical sciences, Earth and Planetary Sciences (miscellaneous), Wave vector, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Earth-Surface Processes, Water Science and Technology, Physics, Ecology, Waves in plasmas, Paleontology, Forestry, Polarization (waves), Computational physics, Geophysics, 13. Climate action, Space and Planetary Science, Magnetosphere of Saturn, Physics::Space Physics, Mode coupling
Abstract

[1] The Cassini mission crossed the source region of the Saturn kilometric radiation (SKR) on 17 October 2008. On this occasion, the Radio and Plasma Wave Science (RPWS) experiment detected both local and distant radio sources, while plasma parameters were measured in situ by the magnetometer and the Cassini Plasma Spectrometer. A goniopolarimetric inversion was applied to RPWS three-antenna electric measurements to determine the wave vector k and the complete state of polarization of detected waves. We identify broadband extraordinary (X) mode as well as narrowband ordinary (O) mode SKR at low frequencies. Within the source region, SKR is emitted just above the X mode cutoff frequency in a hot plasma, with a typical electron-to-wave energy conversion efficiency of ∼1% (2% peak). The knowledge of the k vector is then used to derive the locus of SKR sources in the kronian magnetosphere, which shows X and O components emanating from the same regions. We also compute the associated beaming angle at the source θ′ = (k, −B) either from (1) in situ measurements or a model of the magnetic field vector (for local to distant sources) or (2) polarization measurements (for local sources). Obtained results, similar for both modes, suggest quasi-perpendicular emission for local sources, whereas the beaming pattern of distant sources appears as a hollow cone with a frequency-dependent constant aperture angle: θ′ = 75° ± 15° below 300 kHz, decreasing at higher frequencies to reach θ′ (1000 kHz) = 50° ± 25°. Finally, we investigate quantitatively the SKR polarization state, observed to be strongly elliptical at the source, and quasi-purely circular for sources located beyond approximately two kronian radii. We show that conditions of weak mode coupling are achieved along the raypath, under which the magnetoionic theory satisfactorily describes the evolution of the observed polarization. These results are analyzed comparatively with the auroral kilometric radiation at Earth.

Published
2011

26. Alfvén : Magnetosphere -Ionosphere Connection Explorers

Author

Dhiren Kataria, J. A. Davies, J. Manninen, Laurent Lamy, Betty Lanchester, Joachim Vogt, Yu. V. Khotyaintsev, Kirsti Kauristie, Mike Hapgood, Stephen E. Milan, E. Turunen, F. Mottez, T. Chust, Alain Roux, P. Louarn, Anastasios Anastasiadis, Masatoshi Yamauchi, Octav Marghitu, Milan Maksimovic, Anasuya Aruliah, Michel Parrot, R. Pottelette, Göran Marklund, E. A. Lucek, Vincent Génot, Maria Hamrin, Laurence Rezeau, Jean-Louis Pinçon, Christopher J. Owen, F. Pitout, Roberto Bruno, Gerhard Haerendel, P. Canu, Baptiste Cecconi, Ingrid Sandahl, I. Zouganelis, Philippe Zarka, Aurélie Marchaudon, Ioannis A. Daglis, Clare E. J. Watt, C. H. Perry, S. Kemble, C. Briand, Joran Moen, M. W. Dunlop, Rickard Lundin, Jim Wild, Olga Alexandrova, Sebastien Hess, Andrew Fazakerley, Tuija Pulkkinen, P.-L. Blelly, Nikolai Østgaard, Dominique Fontaine, Arne Pedersen, Holger Nilsson, I. J. Rae, Andrew Walsh, Hannu Koskinen, Colin Forsyth, Björn Gustavsson, Matthieu Berthomier, Ingmar Sandberg, Laboratoire de Physique des Plasmas (LPP), Université Paris-Sud - Paris 11 (UP11)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-École polytechnique (X)-Sorbonne Universités-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Mullard Space Science Laboratory (MSSL), University College of London [London] (UCL), Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Atmospheric Physics Laboratory [UCL London], Institut de recherche en astrophysique et planétologie (IRAP), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), ONERA, Finnish Meteorological Institute (FMI), Swedish Institute of Space Physics [Kiruna] (IRF), Max-Planck-Institut für Extraterrestrische Physik (MPE), Department of Physics and Astronomy [Leicester], University of Leicester, Laboratoire Univers et Théories (LUTH (UMR_8102)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de physique et chimie de l'environnement (LPCE), Université d'Orléans (UO)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), STFC Rutherford Appleton Laboratory (RAL), Science and Technology Facilities Council (STFC), Université Paris-Sud - Paris 11 (UP11)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-École polytechnique (X)-Sorbonne Universités-Sorbonne Université (SU)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École polytechnique (X)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS), 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), Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), 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 sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7), 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, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)

Subjects
Cosmic Vision, 010504 meteorology & atmospheric sciences, Magnetosphere, 01 natural sciences, 7. Clean energy, Physics::Geophysics, [PHYS.PHYS.PHYS-PLASM-PH]Physics [physics]/Physics [physics]/Plasma Physics [physics.plasm-ph], High latitude, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Physics, [PHYS]Physics [physics], Astronomy, Astronomy and Astrophysics, Plasma, Connection (mathematics), Solar wind, Space and Planetary Science, Physics::Space Physics, Astrophysics::Earth and Planetary Astrophysics, Ionosphere, Energy source, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

The aurorae are dynamic, luminous displays that grace the night skies of Earth’s high latitude regions. The solar wind emanating from the Sun is their ultimate energy source, but the chain of plasma physical processes leading to auroral displays is complex. The special conditions at the interface between the solar wind-driven magnetosphere and the ionospheric environment at the top of Earth’s atmosphere play a central role. In this Auroral Acceleration Region (AAR) persistent electric fields directed along the magnetic field accelerate magnetospheric electrons to the high energies needed to excite luminosity when they hit the atmosphere. The “ideal magnetohydrodynamics” description of space plasmas which is useful in much of the magnetosphere cannot be used to understand the AAR. The AAR has been studied by a small number of single spacecraft missions which revealed an environment rich in wave-particle interactions, plasma turbulence, and nonlinear acceleration processes, acting on a variety of spatio-temporal scales. The pioneering 4-spacecraft Cluster magnetospheric research mission is now fortuitously visiting the AAR, but its particle instruments are too slow to allow resolve many of the key plasma physics phenomena. The Alfvén concept is designed specifically to take the next step in studying the aurora, by making the crucial high-time resolution, multi-scale measurements in the AAR, needed to address the key science questions of auroral plasma physics. The new knowledge that the mission will produce will find application in studies of the Sun, the processes that accelerate the solar wind and that produce aurora on other planets.

Published
2011

27. Bifurcated current sheet: model and Cluster observations

Author

Jean-André Sauvaud, Vincent Génot, Fabrice Mottez, André Balogh, P. Louarn, G. Fruit, Centre d'étude spatiale des rayonnements (CESR), Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées, Centre d'étude des environnements terrestre et planétaires (CETP), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Blackett Laboratory, Imperial College London, Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)

Subjects
010504 meteorology & atmospheric sciences, 01 natural sciences, [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], symbols.namesake, Current sheet, 0103 physical sciences, Kinetic equilibrium, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Physics, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Cluster observations, Astronomy and Astrophysics, Plasma, Magnetic field, Computational physics, Temperature gradient, Amplitude, Distribution function, Maxwell's equations, Space and Planetary Science, Physics::Space Physics, symbols, Atomic physics, Magnetotail, Vector potential
Abstract

Cluster observations have recently confirmed previous ISEE and Geotail observations showing that the magnetotail current sheet can present a bifurcated structure with two off-centre current peaks. We show in this paper that such a structure can be described by a kinetic tangential equilibrium which is an exact solution of the Vlasov Maxwell equations. A tangential equilibrium is characterized by a bulk plasma velocity and magnetic field perpendicular to the density and/or temperature gradient direction. The particle distribution functions are sums of an infinite number of elementary functions parametrized by a vector potential. The model is consistent with Cluster observations of a plasma density plateau between the current peaks and the typical size and amplitude of the current distribution. We briefly review existing models and propose some studies which could be carried out with our model.

Published
2005

28. Alfvén wave interaction with inhomogeneous plasmas: acceleration and energy cascade towards small-scales

Author

V. Génot, P. Louarn, F. Mottez, Astronomy Unit [London] (AU), Queen Mary University of London (QMUL), Centre d'étude spatiale des rayonnements (CESR), Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées, Centre d'étude des environnements terrestre et planétaires (CETP), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Université Fédérale Toulouse Midi-Pyrénées-Météo-France -Institut de Recherche pour le Développement (IRD)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)

Subjects
Atmospheric Science, 010504 meteorology & atmospheric sciences, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, 7. Clean energy, 01 natural sciences, Electric charge, 010305 fluids & plasmas, [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], Alfvén wave, symbols.namesake, Physics::Plasma Physics, 0103 physical sciences, Earth and Planetary Sciences (miscellaneous), lcsh:Science, Debye length, 0105 earth and related environmental sciences, Physics, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], lcsh:QC801-809, Geology, Astronomy and Astrophysics, Plasma, Plasma acceleration, lcsh:QC1-999, Charged particle, Computational physics, Particle acceleration, lcsh:Geophysics. Cosmic physics, Classical mechanics, Space and Planetary Science, Energy cascade, symbols, lcsh:Q, lcsh:Physics
Abstract

Investigating the process of electron acceleration in auroral regions, we present a study of the temporal evolution of the interaction of Alfvén waves (AW) with a plasma inhomogeneous in a direction transverse to the static magnetic field. This type of inhomogeneity is typical of the density cavities extended along the magnetic field in auroral acceleration regions. We use self-consistent Particle In Cell (PIC) simulations which are able to reproduce the full nonlinear evolution of the electromagnetic waves, as well as the trajectories of ions and electrons in phase space. Physical processes are studied down to the ion Larmor radius and electron skin depth scales. We show that the AW propagation on sharp density gradients leads to the formation of a significant parallel (to the magnetic field) electric field (E-field). It results from an electric charge separation generated on the density gradients by the polarization drift associated with the time varying AW E-field. Its amplitude may reach a few percents of the AW E-field. This parallel component accelerates electrons up to keV energies over a distance of a few hundred Debye lengths, and induces the formation of electron beams. These beams trigger electrostatic plasma instabilities which evolve toward the formation of nonlinear electrostatic structures (identified as electron holes and double layers). When the electrostatic turbulence is fully developed we show that it reduces the further wave/particle exchange. This sequence of mechanisms is analyzed with the program WHAMP, to identify the instabilities at work and wavelet analysis techniques are used to characterize the regime of energy conversions (from electromagnetic to electrostatic structures, from large to small length scales). This study elucidates a possible scenario to account for the particle acceleration and the wave dissipation in inhomogeneous plasmas. It would consist of successive phases of acceleration along the magnetic field, the development of an electrostatic turbulence, the thermalization and the heating of the plasma. Space plasma physics (charged particle motion and acceleration; numerical studies).

Published
2004

29. On the propagation of low-frequency fluctuations in the plasma sheet: 2. Characterization of the MHD eigenmodes and physical implications

Author

D. Le Quéau, J. A. Sauvaud, G. Fruit, Nicole Cornilleau-Wehrlin, André Balogh, Elizabeth Lucek, H. Rème, P. Louarn, E. Budnik, C. Jacquey, Department of Mathematics, University of Waikato, The University of Waikato, Centre d'étude spatiale des rayonnements (CESR), Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées, Imperial College London, Centre d'étude des environnements terrestre et planétaires (CETP), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)

Subjects
Atmospheric Science, 010504 meteorology & atmospheric sciences, Meteorology, Soil Science, Aquatic Science, Low frequency, Oceanography, 01 natural sciences, [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], Geochemistry and Petrology, Normal mode, 0103 physical sciences, Substorm, Earth and Planetary Sciences (miscellaneous), MHD waves and instabilities, 010303 astronomy & astrophysics, plasma sheet, storms and substorms, 0105 earth and related environmental sciences, Earth-Surface Processes, Water Science and Technology, Physics, magnetotail, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Ecology, Oscillation, Plasma sheet, Paleontology, Forestry, Wavelength, Geophysics, Amplitude, Space and Planetary Science, Quantum electrodynamics, Physics::Space Physics, Magnetohydrodynamics
Abstract

[1] In a first analysis of the low-frequency fluctuations observed by Cluster during a crossing of the plasma sheet [Louarn et al., 2004], we identify oscillations that likely correspond to MHD eigenmodes. They are intense (10 nT), have a rather short period (20–25 s), have a wavelength of ∼5 Re, and are observed during an active period that follows a substorm onset. We show here that they combine both sausage and kink modes propagating in the x direction with a common spectral peak at ∼0.04 Hz, the sausage oscillations presenting also a secondary peak at 0.13 Hz. Using a complete theory of the linear MHD response of the plasma sheet, we reconstruct the sheet oscillations starting from given external perturbations. This method leads to quantitative predictions concerning the magnetic and pressure fluctuations. The existence of natural resonant frequencies of the sheet can indeed be foreseen and the relative weight of the kink-like and sausage-like modes can also be estimated. We show that the kink mode (0.04 Hz) and the high-frequency sausage mode (0.14 Hz) are perfectly compatible with the MHD model of Harris sheet oscillations, with wavelength of ∼6 Re and ∼3 Re, respectively. The corresponding amplitude of the pressure and magnetic fluctuations also appears to be remarkably consistent with the theoretical predictions. Conversely, the low-frequency sausage mode (0.04 Hz) is hardly explained by the MHD model. We propose that it could be a nonideal MHD or a kinetic mode, as the tearing mode.

Published
2004

30. On the propagation of low-frequency fluctuations in the plasma sheet: 1. Cluster observations and magnetohydrodynamic analysis

Author

H. Rème, D. Le Quéau, J. A. Sauvaud, P. Louarn, E. Budnik, C. Jacquey, André Balogh, Elizabeth Lucek, G. Fruit, Centre d'étude spatiale des rayonnements (CESR), Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées, Department of Mathematics, University of Waikato, The University of Waikato, Imperial College London, Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)

Subjects
Atmospheric Science, 010504 meteorology & atmospheric sciences, Soil Science, Magnetosphere, Aquatic Science, Oceanography, 01 natural sciences, 010305 fluids & plasmas, [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], Physics::Plasma Physics, Geochemistry and Petrology, Normal mode, 0103 physical sciences, Substorm, Earth and Planetary Sciences (miscellaneous), MHD waves and instabilities, Magnetohydrodynamic drive, plasma sheet, storms and substorms, 0105 earth and related environmental sciences, Earth-Surface Processes, Water Science and Technology, Physics, magnetotail, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Ecology, Oscillation, Plasma sheet, Paleontology, Forestry, Geophysics, Computational physics, Wavelength, 13. Climate action, Space and Planetary Science, Physics::Space Physics, Magnetohydrodynamics
Abstract

[1] Low-frequency pressure and magnetic oscillations observed by Cluster in the plasma sheet are investigated with the aim of determining if they are magnetohydrodynamic (MHD) eigenmodes. We analyze the plasma sheet crossing occurring on 22 August 2001, as the magnetosphere was first quiet and then active, and compare the observations with theoretical results concerning the MHD propagation in a Harris sheet. The theory shows that the eigenmodes have periods scaled by a characteristic time, τ, equal to the ratio between (1) the thickness of the sheet and (2) the sound speed. Using the Cluster 4 spacecraft, we estimate the sheet thickness and determine this characteristic time. It is compared with the typical periods of the fluctuations deduced from a wavelet analysis. During the quiet period, the fluctuations have periods larger than 100 s or 15τ. Discrete MHD eigenmodes with such periods would have wavelengths larger than the distance separating Cluster from Earth (18 RE). Thus they are very unlikely interpreted as freely propagating eigenmodes. However, fluctuations of shorter periods (∼20 s) are observed during and just after the substorm onset. We demonstrate that they are compatible with the fundamental MHD eigenmode (kink-like mode) of the sheet, with a wavelength of ∼5–6 RE, their direction of propagation being not determined at this stage of the analysis. We thus conclude that freely propagating MHD eigenmodes observable by Cluster would have periods that hardly exceed a minute for typical plasma sheet parameters (thickness of 1 RE, temperature of a few keV).

Published
2004

31. The Cassini Radio and Plasma Wave Investigation

Author

D. A. Gurnett, W. S. Kurth, D. L. Kirchner, G. B. Hospodarsky, T. F. Averkamp, P. Zarka, A. Lecacheux, R. Manning, A. Roux, P. Canu, N. Cornilleau-Wehrlin, P. Galopeau, A. Meyer, R. Boström, G. Gustafsson, J.-E. Wahlund, L. Åhlen, H. O. Rucker, H. P. Ladreiter, W. Macher, L. J. C. Woolliscroft, H. Alleyne, M. L. Kaiser, M. D. Desch, W. M. Farrell, C. C. Harvey, P. Louarn, P. J. Kellogg, K. Goetz, and A. Pedersen

Subjects
010504 meteorology & atmospheric sciences, 0103 physical sciences, 010303 astronomy & astrophysics, 01 natural sciences, 0105 earth and related environmental sciences
Published
2004

32. On the asymptotic theory of localized structures in a thin two-dimensional Harris current sheet: plasmoids, multiplasmoids and X points

Author

A. Tur, P. Louarn, Vincent Génot, D. Le Queau, V. Yanovsky, Centre d'étude spatiale des rayonnements (CESR), Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées, institute for single crystals, national academy of science, 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, Asymptotic analysis, 010504 meteorology & atmospheric sciences, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Vlasov equation, Plasmoid, Condensed Matter Physics, 01 natural sciences, 010305 fluids & plasmas, [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], Nonlinear system, symbols.namesake, Current sheet, Maxwell's equations, 0103 physical sciences, Physics::Space Physics, symbols, Finite set, 0105 earth and related environmental sciences, Mathematical physics
Abstract

We develop a new asymptotic method of resolution of the two-dimensional equilibrium equation of collisionless plasmas described by the Maxwell–Vlasov equations. This method differs from the classical one proposed by K. Schindler [Earth's Magnetospheric Processes (ed. B. M. McCormac). Norwood, MA: Reidel, 1972, pp. 200–209.] since we consider free-boundary plasmas. Our method is a generalization of the usual multiscale asymptotic developments. The first-approximation asymptotic solutions are found from the elimination of increasing and singular terms in the next approximation. We apply the method to the mathematical description of nonlinear structures that may form in neutral sheets. Particular solutions describing localized plasmoids (O-point configuration) as well as X-point magnetic configurations are obtained. We also find more general solutions describing a finite number of ‘magnetic islands' (multiplasmoid solutions) separated by X points.

Published
2001

33. Electron acceleration by Alfvén waves in density cavities

Author

Vincent Génot, P. Louarn, Fabrice Mottez, Centre d'étude spatiale des rayonnements (CESR), Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées, Centre d'étude des environnements terrestre et planétaires (CETP), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), 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
Space Plasma Physics: Charged particle motion and acceleration, Atmospheric Science, Guiding center, 010504 meteorology & atmospheric sciences, Wave propagation, Soil Science, Electron, Aquatic Science, Oceanography, 01 natural sciences, Alfvén wave, [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], Optics, Geochemistry and Petrology, Physics::Plasma Physics, Electric field, 0103 physical sciences, Earth and Planetary Sciences (miscellaneous), Space Plasma Physics: Wave/particle interactions, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, Earth-Surface Processes, Water Science and Technology, Physics, Ecology, Space Plasma Physics: Numerical simulation studies, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], business.industry, Paleontology, Forestry, Computational physics, Magnetic field, Particle acceleration, Wavelength, Geophysics, Space and Planetary Science, Physics::Space Physics, business, Magnetospheric Physics: Auroral phenomena
Abstract

A new electromagnetic two-dimensional guiding center particle in cell (PIC) code is used to investigate the propagation of an Alfven wave in the perpendicular density gradients that characterize the edges of the auroral density cavities. It is shown that the wave planes are strongly distorted by the inhomogeneities of the plasma and that a significant electric field develops in the direction parallel to the background magnetic field during the propagation. This field efficiently accelerates the electrons in the parallel direction, and the incident wave is thus strongly absorbed. The associated dissipation rate is sufficiently strong to explain a complete wave absorption on the density gradients over a fraction of wavelength. The electron parallel acceleration is also characterized. It corresponds to a global parallel acceleration of the electron population. These PIC simulations suggest that the perpendicular density gradients corresponding to the auroral plasma cavities play an important role in the auroral particle acceleration.

Published
2000

34. Beaming Cone of Io-Controlled Jovian Decameter Radio Emission and Existence of Localized Active Longitude

Author

Mohammed Y. Boudjada, Patrick H. M. Galopeau, HELIOS - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Space Research Institute of Austrian Academy of Sciences (IWF), Austrian Academy of Sciences (OeAW), H.O. Rucker, W.S. Kurth, P. Louarn, and and G. Fischer (eds)

Subjects
Physics, 010504 meteorology & atmospheric sciences, Cyclotron, Astrophysics, 01 natural sciences, Instability, Jovian, Flattening, law.invention, Magnetic field, Azimuth, [SDU]Sciences of the Universe [physics], 13. Climate action, law, Physics::Space Physics, 0103 physical sciences, Astrophysics::Earth and Planetary Astrophysics, Maser, Longitude, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences
Abstract

International audience; The occurrence probability of the Jovian decameter radio emissions depends on two essential parameters: the central meridian longitude (CML) and the orbital phase of the satellite Io. Four main zones of enhanced occurrence probability emerge from the CML-Io phase diagram: the so-called Io-controlled sources Io-A, Io-B, Io-C and Io-D. We study the compatibility of the location of these sources with the existence of a specific active longitude range, anchored in Jupiter's magnetic field, and favoring the radio emissions. A theoretical model, based on the cyclotron maser instability (CMI), was proposed a few years ago in order to explain the existence of such active longitudes, assuming that the radiation was emitted at the local gyrofrequency in a hollow cone of constant angle, along a magnetic field line carried away by Io through its revolution around Jupiter. Unfortunately this model was not able to justify the dimension in longitude of all the Io-controlled sources, in particular those located in the Jovian southern hemisphere (Io-C and Io-D). We show that the azimuthal distribution of the four occurrence regions (Io-A, Io-B, Io-C and Io-D) around the gradient of the local magnetic field is not constant so that the emission cone (in each Jovian hemisphere) presents a significant flattening in the direction of the magnetic field vector. Introducing a beaming cone with an elliptical section makes the location and extension in longitude of the sources (in the CML-Io phase diagram) compatible with the existence of an active longitude. A theory of the CMI, acting in an inhomogeneous medium in which the magnetic field vector and the gradient of its modulus are not aligned, shall be required in order to justify the flattening of the emission cone.

Published
2011

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