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| Titel |
The (in)efficiency of plasma mixing in collisionless turbulence |
| VerfasserIn |
Pierre Henri, Francesco Califano, Stefano Markidis, Giovanni Lapenta |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250097163
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| Publikation (Nr.) |
 EGU/EGU2014-12714.pdf |
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| Zusammenfassung |
| A relevant mixing between the solar wind and the magnetospheric plasma is observed at low latitude even in northward magnetic field conditions, when the solar wind and magnetospheric magnetic fields are nearly parallel thus preventing the development of magnetic reconnection. An alternative mechanism to reconnection can be found in the Kelvin-Helmholtz instability, able to provide an efficient mechanism for the formation of a mixing layer.
The nonlinear evolution of the Kelvin-Helmholtz instability indeed enables to efficiently mix two media separated by a velocity shear when the collisionality is high enough, through the effect of viscosity and/or resistivity. But what happens in the case of collisionless media such as most space plasma?
Using full kinetic plasma simulations from MHD to kinetic electron scales, we show that the nonlinear evolution of a magnetized, collisionsless shear plasma flow forms a turbulent layer that is however highly inefficient from a mixing point of view. The results are discussed in the context of the magnetosphere-magnetosheath boundary, where we show that the magnetosphere and magnetosheath plasma remains well separated even in the turbulent layer.
The research leading to these results has received funding from the European Commission’s Seventh Framework Programme (FP7/20072013) under the grant agreement SWIFF (Project No. 263340, www.swiff.eu). We acknowledge the access to the HPC resources of CINECA made available within the Distributed European Computing Initiative by the PRACE-2IP, receiving funding from the European Community's Seventh Framework Programme (FP7/2007-2013) under grant agreement RI-283493 and project number 2012071282. This work was supported by the Italian Supercomputing Center CINECA under the ISCRA initiative. |
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