Dynamic unmagnetized plasma in the diamagnetic cavity around comet 67P/Churyumov–Gerasimenko
| Autor: | James L. Burch, Hans Nilsson, Martin Rubin, Herbert Gunell, Jérôme Moré, Charlotte Goetz, Bruce T. Tsurutani, Gaëtan Wattieaux, X. Vallières, Pierre Henri, Rajkumar Hajra, Zoltán Németh, Ingo Richter, N. Gilet, Anders Eriksson |
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| Přispěvatelé: | 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), Plasmas Réactifs Hors Equilibre (LAPLACE-PRHE), LAboratoire PLasma et Conversion d'Energie (LAPLACE), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées, Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], Jet Propulsion Laboratory (JPL), California Institute of Technology (CALTECH)-NASA, Belgian Institute for Space Aeronomy / Institut d'Aéronomie Spatiale de Belgique (BIRA-IASB), Swedish Institute of Space Physics [Kiruna] (IRF), Swedish Institute of Space Physics [Uppsala] (IRF), Wigner Research Centre for Physics [Budapest], Hungarian Academy of Sciences (MTA), Southwest Research Institute [Boulder] (SwRI), Physikalisches Institut [Bern], Universität Bern [Bern] |
| Jazyk: | angličtina |
| Rok vydání: | 2018 |
| Předmět: |
010504 meteorology & atmospheric sciences
530 Physics Comet Electron 01 natural sciences law.invention Orbiter law Ionization 0103 physical sciences Relative density 010303 astronomy & astrophysics 0105 earth and related environmental sciences Plasma density Physics comets: individual: 67P/Churyumov–Gerasimenko [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph] 520 Astronomy comets: general Astronomy and Astrophysics Plasma 620 Engineering methods: data analysis Space and Planetary Science Diamagnetism Atomic physics methods: observational |
| Zdroj: | Monthly Notices of the Royal Astronomical Society Monthly Notices of the Royal Astronomical Society, Oxford University Press (OUP): Policy P-Oxford Open Option A, 2018, 475 (3), pp.4140-4147. ⟨10.1093/mnras/sty094⟩ Hajra, Rajkumar; Henri, Pierre; Vallières, Xavier; Moré, Jerome; Gilet, Nicolas; Wattieaux, Gaetan; Goetz, Charlotte; Richter, Ingo; Tsurutani, Bruce T; Gunell, Herbert; Nilsson, Hans; Eriksson, Anders I; Nemeth, Zoltan; Burch, James L; Rubin, Martin (2018). Dynamic unmagnetized plasma in the diamagnetic cavity around comet 67P/Churyumov–Gerasimenko. Monthly notices of the Royal Astronomical Society, 475(3), pp. 4140-4147. Oxford University Press 10.1093/mnras/sty094 |
| ISSN: | 0035-8711 1365-2966 |
| DOI: | 10.1093/mnras/sty094⟩ |
| Popis: | International audience; The Rosetta orbiter witnessed several hundred diamagnetic cavity crossings (unmagnetized regions) around comet 67P/Churyumov–Gerasimenko during its two year survey of the comet. The characteristics of the plasma environment inside these diamagnetic regions are studied using in situ measurements by the Rosetta Plasma Consortium instruments. Although the unmagnetized plasma density has been observed to exhibit little dynamics compared to the very dynamical magnetized cometary plasma, we detected several localized dynamic plasma structures inside those diamagnetic regions. These plasma structures are not related to the direct ionization of local cometary neutrals. The structures are found to be steepened, asymmetric plasma enhancements with typical rising-to-descending slope ratio of ∼2.8 (±1.9), skewness ∼0.43 (±0.36), mean duration of ∼2.7 (±0.9) min and relative density variation ΔN/N of ∼0.5 (±0.2), observed close to the electron exobase. Similar steepened plasma density enhancements were detected at the magnetized boundaries of the diamagnetic cavity as well as outside the diamagnetic region. The plausible scalelength and propagation direction of the structures are estimated from simple plasma dynamics considerations. It is suggested that they are large-scale unmagnetized plasma enhancements, transmitted from the very dynamical outer magnetized region to the inner magnetic field-free cavity region. |
| Databáze: | OpenAIRE |
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