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Titel |
Reconnection current sheet structure in a turbulent medium |
VerfasserIn |
E. T. Vishniac, S. Pillsworth, G. Eyink, G. Kowal, A. Lazarian, S. Murray |
Medientyp |
Artikel
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Sprache |
Englisch
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ISSN |
1023-5809
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Digitales Dokument |
URL |
Erschienen |
In: Nonlinear Processes in Geophysics ; 19, no. 6 ; Nr. 19, no. 6 (2012-11-08), S.605-610 |
Datensatznummer |
250014259
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Publikation (Nr.) |
copernicus.org/npg-19-605-2012.pdf |
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Zusammenfassung |
In the presence of turbulence, magnetic field lines lose their dynamical identity and
particles entrained on field lines diffuse through space at a rate determined by the amplitude of the turbulence.
In previous work (Lazarian and Vishniac, 1999; Kowal et al., 2009; Eyink et
al., 2011) we showed that this leads to reconnection speeds which are independent
of resistivity. In particular, in Kowal et
al. (2009) we showed that numerical simulations were consistent with the predictions
of this model. Here we examine the structure of the current sheet in simulations of turbulent reconnection. Laminar flows
consistent with the Sweet-Parker reconnection model produce very thin and well ordered currents sheets. On the other hand,
the simulations of Kowal et
al. (2009) show a strongly disordered state even for relatively low levels of turbulence. Comparing
data cubes with and without reconnection, we find that large scale field reversals are the cumulative effect of many individual
eddies, each of which has magnetic properties which are not very different from turbulent eddies in a homogeneous background.
This implies that the properties of stationary and homogeneous MHD turbulence are a reasonable guide to understanding turbulence
during large scale magnetic reconnection events. In addition, dissipation and high energy particle acceleration during reconnection
events take place over a macroscopic volume, rather than being confined to a narrow zone whose properties depend on microscopic
transport coefficients. |
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