@article{Franci:2016:1/91,
author = {Franci, L and Landi, S and Matteini, L and Verdini, A and Hellinger, P},
doi = {1/91},
journal = {Astrophysical Journal},
title = {Plasma beta dependence of the ion-scale spectral break of solar wind turbulence: high-resolution 2D hybrid simulations},
url = {http://dx.doi.org/10.3847/1538-4357/833/1/91},
volume = {833},
year = {2016}
}

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TY  - JOUR
AB  - We investigate properties of the ion-scale spectral break of solar wind turbulence by means of two-dimensional high-resolution hybrid particle-in-cell simulations. We impose an initial ambient magnetic field perpendicular to the simulation box and add a spectrum of in-plane, large-scale, magnetic and kinetic fluctuations. We perform a set of simulations with different values of the plasma β, distributed over three orders of magnitude, from 0.01 to 10. In all cases, once turbulence is fully developed, we observe a power-law spectrum of the fluctuating magnetic field on large scales (in the inertial range) with a spectral index close to −5/3, while in the sub-ion range we observe another power-law spectrum with a spectral index systematically varying with β (from around −3.6 for small values to around −2.9 for large ones). The two ranges are separated by a spectral break around ion scales. The length scale at which this transition occurs is found to be proportional to the ion inertial length, d i , for β Lt 1 and to the ion gyroradius, ${\rho }_{i}={d}_{i}\sqrt{\beta }$, for β Gt 1, i.e., to the larger between the two scales in both the extreme regimes. For intermediate cases, i.e., β ~ 1, a combination of the two scales is involved. We infer an empiric relation for the dependency of the spectral break on β that provides a good fit over the whole range of values. We compare our results with in situ observations in the solar wind and suggest possible explanations for such a behavior.
AU  - Franci,L
AU  - Landi,S
AU  - Matteini,L
AU  - Verdini,A
AU  - Hellinger,P
DO  - 1/91
PY  - 2016///
SN  - 0004-637X
TI  - Plasma beta dependence of the ion-scale spectral break of solar wind turbulence: high-resolution 2D hybrid simulations
T2  - Astrophysical Journal
UR  - http://dx.doi.org/10.3847/1538-4357/833/1/91
UR  - http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000390792000003&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=1ba7043ffcc86c417c072aa74d649202
UR  - http://hdl.handle.net/10044/1/44545
VL  - 833
ER  - 

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