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| Titel |
New observations of flux ropes in the magnetotail reconnection region |
| VerfasserIn |
Shiyong Huang, Alessandro Retino, Tai Phan, W. Bill Daughton, Andris Vaivads, Homa Karimabadi, Ye Pang, Meng Zhou, Fouad Sahraoui, Guanlai Li, Zhigang Yuan, Xiaohua Deng, Huishan Fu, Song Fu, Dedong Wang |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250127266
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| Publikation (Nr.) |
 EGU/EGU2016-7122.pdf |
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| Zusammenfassung |
| Magnetic reconnection is a fundamental physical process that enables the rapid
transfer of magnetic energy into plasma kinetic and thermal energy in the laboratory,
astrophysical and space plasma. Flux ropes have been suggested to play important role in
controlling the micro-scale physics of magnetic reconnection and electron acceleration.
In this presentation, we report new observations of flux ropes in the magnetotail
reconnection region based on the Cluster multi-spacecraft data. Firstly, two consecutive
magnetic flux ropes, separated by less than 30 s (Δt < 30 s), are observed within
one magnetic reconnection diffusion region without strong guide field. In spite
of the small but non-trivial global scale negative guide field (–By), there exists a
directional change of the core fields of two flux ropes, i.e. –By for the first one,
and +By for the second one. This is inconsistent with any theory and simulations.
Therefore, we suggest that the core field of flux ropes is formed by compression of
the local preexisting By, and that the directional change of core field is due to the
change of local preexisting By. Such a change in ambientBy might be caused by
some microscale physics. Secondary, we will present in-situ observations of a small
scale flux rope locally formed at the separatrix region of magnetic reconnection
without large guide field. Bidirectional electron beams (cold and hot beams) and
density cavity accompanied by intense wave activities substantiate the crossing
of the separatrix region. Density compression and one parallel electron beam are
detected inside the flux rope. We suggest that this flux rope is locally generated at the
separatrix region due to the tearing instability within the separatrix current layer. This
observation sheds new light on the 3D picture of magnetic reconnection in space plasma. |
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