Properties of the singing comet waves in the 67P/Churyumov-Gerasimenko plasma environment as observed by the Rosetta mission

Autor: Ingo Richter, Pierre Henri, Xavier Vallières, F. L. Johansson, Hugo Breuillard, Anders Eriksson, Charlotte Goetz, Elias Odelstad, Rajkumar Hajra, L. Bucciantini, Martin Volwerk, Tomas Karlsson
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)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université d'Orléans (UO)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Centre National d’Études Spatiales [Paris] (CNES), Laboratoire de Physique des Plasmas (LPP), 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), Space Research Institute of Austrian Academy of Sciences (IWF), Austrian Academy of Sciences (OeAW), Department of Space and Plasma Physics [Stockholm], KTH School of Electrical Engineering, Royal Institute of Technology [Stockholm] (KTH )-Royal Institute of Technology [Stockholm] (KTH ), Swedish Institute of Space Physics [Uppsala] (IRF), Technische Universität Braunschweig [Braunschweig], 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), Université Paris-Saclay-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11)-École polytechnique (X)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig]
Jazyk: angličtina
Rok vydání: 2019
Předmět:
010504 meteorology & atmospheric sciences
Comet
observational [methods]
Astrophysics
01 natural sciences
general [comets]
Fusion
plasma och rymdfysik
comets: individual: 67P
Astronomi
astrofysik och kosmologi
Physics::Plasma Physics
0103 physical sciences
data analysis [methods]
Astronomy
Astrophysics and Cosmology
waves
010303 astronomy & astrophysics
0105 earth and related environmental sciences
Churyumov-Gerasimenko
Physics
Spacecraft
[SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph]
business.industry
comets: general
Astronomy
Astronomy and Astrophysics
Plasma
plasmas
Methods observational
methods: data analysis
Fusion
Plasma and Space Physics
On board
13. Climate action
Space and Planetary Science
Physics::Space Physics
Astrophysics::Earth and Planetary Astrophysics
methods: observational
business
individual: 67P/Churyumov-Gerasimenko [comets]
Zdroj: Astronomy and Astrophysics-A&A
Astronomy and Astrophysics-A&A, EDP Sciences, 2019, 630, pp.A39. ⟨10.1051/0004-6361/201834876⟩
ISSN: 0004-6361
DOI: 10.1051/0004-6361/201834876⟩
Popis: Using in situ measurements from different instruments on board the Rosetta spacecraft, we investigate the properties of the newly discovered low-frequency oscillations, known as singing comet waves, that sometimes dominate the close plasma environment of comet 67P/Churyumov-Gerasimenko. These waves are thought to be generated by a modified ion-Weibel instability that grows due to a beam of water ions created by water molecules that outgass from the comet. We take advantage of a cometary outburst event that occurred on 2016 February 19 to probe this generation mechanism. We analyze the 3D magnetic field waveforms to infer the properties of the magnetic oscillations of the cometary ion waves. They are observed in the typical frequency range (similar to 50 mHz) before the cometary outburst, but at similar to 20 mHz during the outburst. They are also observed to be elliptically right-hand polarized and to propagate rather closely (similar to 0-50 degrees) to the background magnetic field. We also construct a density dataset with a high enough time resolution that allows us to study the plasma contribution to the ion cometary waves. The correlation between plasma and magnetic field variations associated with the waves indicates that they are mostly in phase before and during the outburst, which means that they are compressional waves. We therefore show that the measurements from multiple instruments are consistent with the modified ion-Weibel instability as the source of the singing comet wave activity. We also argue that the observed frequency of the singing comet waves could be a way to indirectly probe the strength of neutral plasma coupling in the 67P environment.
Databáze: OpenAIRE
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