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The intermittency of density fluctuations in the solar wind at kinetic scales has been examined using high time resolution Faraday cup measurements from the Spektr-R spacecraft. It was found that the probability density functions (PDFs) of…

空间物理 · 物理学 2014-06-23 C. H. K. Chen , L. Sorriso-Valvo , J. Šafránková , Z. Němeček

Fluctuations of solar wind magnetic field and plasma parameters exhibit a typical turbulence power spectrum with a spectral index ranging between $\sim -5/3$ and $\sim -3/2$. In particular, at $1$ AU, the magnetic field spectrum, observed…

空间物理 · 物理学 2019-07-10 R. Bruno , D. Telloni , L. Sorriso-Valvo , R. Marino , R. De Marco , R. DAmicis

We analyse velocity fluctuations in the solar wind at magneto-fluid scales in two datasets, extracted from Wind data in the period 2005-2015, that are characterised by strong or weak expansion. Expansion affects measurements of anisotropy…

太阳与恒星天体物理 · 物理学 2019-04-24 Andrea Verdini , Roland Grappin , Olga Alexandrova , Luca Franci , Simone Landi , Lorenzo Matteini , Emanuele Papini

The anisotropy of turbulence in the fast solar wind, between the ion and electron gyroscales, is directly observed using a multispacecraft analysis technique. Second order structure functions are calculated at different angles to the local…

空间物理 · 物理学 2012-08-20 C. H. K. Chen , T. S. Horbury , A. A. Schekochihin , R. T. Wicks , O. Alexandrova , J. Mitchell

We present a quantitative estimate of the anisotropic power and scaling of magnetic field fluctuations in inertial range magnetohydrodynamic turbulence, using a novel wavelet technique applied to spacecraft measurements in the solar wind.…

等离子体物理 · 物理学 2009-11-13 T. S. Horbury , M. A. Forman , S. Oughton

The solar wind is a structured and complex system, in which the fields vary strongly over a wide range of spatial and temporal scales. As an example, the turbulent activity in the wind affects the evolution in the heliosphere of the…

空间物理 · 物理学 2015-06-19 M. E. Ruiz , S. Dasso , W. H. Matthaeus , J. M. Weygand

Incompressible and isotropic magnetohydrodynamic turbulence in plasms can be described by an exact relation for the energy flux through the scales. This Yaglom-like scaling law has been recently observed in the solar wind above the solar…

空间物理 · 物理学 2015-05-18 V. Carbone , R. Marino , L. Sorriso-Valvo , A. Noullez , R. Bruno

Measurements and simulations of inertial compressive turbulence in the solar wind are characterized by anti-correlated magnetic fluctuations parallel to the mean field and density structures. This signature has been interpreted as…

空间物理 · 物理学 2018-03-14 Trevor A. Bowen , Samuel Badman , Petr Hellinger , Stuart D. Bale

Scaling exponents are the central quantitative prediction of theories of turbulence and in-situ satellite observations of the high Reynolds number solar wind flow have provided an extensive testbed of these. We propose a general, instrument…

太阳与恒星天体物理 · 物理学 2015-06-03 G. Gogoberidze , S. C. Chapman , B. Hnat , M. W. Dunlop

Local scaling and singularity properties of solar wind and geomagnetic time series were analysed using H\"{o}lder exponents $\alpha$. It was shown that in analysed cases due to multifractality of fluctuations $\alpha$ changes from point to…

计算物理 · 物理学 2020-01-29 Z. Vörös , D. Jankovičová

The magnetic variance anisotropy ($\mathcal{A}_m$) of the solar wind has been used widely as a method to identify the nature of solar wind turbulent fluctuations; however, a thorough discussion of the meaning and interpretation of the…

空间物理 · 物理学 2015-06-05 J. M. TenBarge , J. J. Podesta , K. G. Klein , G. G. Howes

We investigate Venus Express (VEX) observations of magnetic field fluctuations performed systematically in the solar wind at 0.72 Astronomical Units (AU), between 2007 and 2009, during the deep minimum of the solar cycle 24. The Power…

空间物理 · 物理学 2015-05-21 Eliza Teodorescu , Marius Echim , Costel Munteanu , Tielong Zhang , Roberto Bruno , Peter Kovacs

The turbulent spectrum of magnetic fluctuations in the solar wind displays a spectral break at ion characteristic scales. At electron scales the spectral shape is not yet completely established. Here, we perform a statistical study of 102…

等离子体物理 · 物理学 2011-11-28 O. Alexandrova , C. Lacombe , A. Mangeney , R. Grappin

The question is addressed to what extent incompressible magnetohydrodynamics (MHD) can describe random magnetic and velocity fluctuations measured in the solar wind. It is demonstrated that distributions of spectral indices for the…

星系天体物理 · 物理学 2015-05-28 Stanislav Boldyrev , Jean Carlos Perez , Joseph E. Borovsky , John J. Podesta

The sun as an oscillator produces frequencies which propagate in the heliosphere, via solar wind, to the terrestrial magnetosphere. We searched for those frequencies in the parameters of the near Earth solar plasma and the geomagnetic…

太阳与恒星天体物理 · 物理学 2016-11-11 Ch. Katsavrias , P. Preka-Papadema , X. Moussas

We have analyzed long-term wind speed time-series from five field sites up to a height of 300 m from the ground. Structure function-based scaling analysis has revealed that the scaling exponents in the mesoscale regime systematically depend…

流体动力学 · 物理学 2015-09-09 V. P. Kiliyanpilakkil , S. Basu , A. Ruiz-Columbié , G. Araya , L. Castillo , B. Hirth , W. Burgett

The interaction between the Earth's magnetic field and the solar wind plasma results in a natural plasma confinement system which stores energy. Dissipation of this energy through Joule heating in the ionosphere can be studied via the…

天体物理学 · 物理学 2016-08-30 N. W. Watkins , M. P. Freeman , C. S. Rhodes , G. Rowlands

Solar wind turbulence is often perceived as weakly compressible and the density fluctuations remain poorly understood both theoretically and observationally. Compressible magnetohydrodynamic simulations provide useful insights into the…

空间物理 · 物理学 2023-04-12 Senbei Du , Hui Li , Zhaoming Gan , Xiangrong Fu

Solar wind magnetic fluctuation spectra exhibit a significant power law steepening at frequencies f>1Hz. The origin of this multi-scaling is investigated through dispersive Hall magnetohydrodynamics. We perform three-dimensional numerical…

天体物理学 · 物理学 2008-11-26 S. Galtier , E. Buchlin

At the electron scales the power spectrum of solar-wind magnetic fluctuations can be highly variable and the dissipation mechanisms of the magnetic energy into the various particle species is under debate. In this paper we investigate data…