In situ evidence of firehose instability in multiple magnetic reconnection
| Autor: | Hugo Breuillard, Filomena Catapano, Olivier Le Contel, Andrey Divin, Alessandro Retinò, Alexandra Alexandrova, Jan Deca, Giulia Cozzani, Lorenzo Matteini |
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| Přispěvatelé: | 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), Saint Petersburg State University (SPBU), Department of Physics [Imperial College London], Imperial College London, Department of Earth Observation Future Missions, European Space Research Institute (ESRIN), European Space Agency (ESA)-European Space Agency (ESA), Swedish Institute of Space Physics [Uppsala] (IRF), Laboratory for Atmospheric and Space Physics [Boulder] (LASP), University of Colorado [Boulder] |
| Rok vydání: | 2020 |
| Předmět: | |
| Zdroj: | EGU General Assembly 2020 EGU General Assembly 2020, May 2020, Vienna, Austria. ⟨10.5194/egusphere-egu2020-18188⟩ |
| Popis: | Energy conversion via reconnecting current sheets is common in space and astrophysical plasma. Frequently, current sheets disrupt at multiple reconnection sites, leading to the formation of plasmoid structures between the sites, which might affect energy conversion. We present in situ observations of multiple reconnection in the Earth’s magnetotail. The observed highly accelerated proton beams parallel to magnetic field and the ion-scale wave-like fluctuations of the whistler type imply the development of firehose instability between two active reconnection sites. The linear wave dispersion relation estimated for the measured plasma parameters, indicates a positive growth rate of the firehose-related electromagnetic fluctuations. The detailed time-space evolution of the plasmoid is obtained by reconstruction of observations with the 2.5D implicit particle-in-cell simulations. In course of time, plasma on the periphery of the plasmoid becomes anisotropic and as it overcomes the firehose marginal stability threshold, the corresponding magnetic field fluctuations arise. The results of observations and simulations suggest that the firehose instability operating between reconnection sites, converts plasma energy of the proton temperature anisotropy to the energy of magnetic field fluctuations, counteracting with the conversion of magnetic energy to the energy of plasma in reconnection sites. |
| Databáze: | OpenAIRE |
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