Colloquium: Magnetohydrodynamic turbulence and time scales in astrophysical and space plasmas

Zhou, Ye; Matthaeus, W. H.; Dmitruk, P.

doi:10.1103/revmodphys.76.1015

Cited by 235 publications

(251 citation statements)

References 96 publications

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“…Simulation results [3,28,36,55,56] and phenomenologies [29,35,57,58] support the notion that small scales are more anisotropic, and achieve their quasitwo-dimensional-type states more rapidly than larger scales.…”

Section: (A) Review Of Observationsmentioning

confidence: 48%

Anisotropy in solar wind plasma turbulence

Oughton

Matthaeus

Wan

et al. 2015

Phil. Trans. R. Soc. A.

128

113

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One contribution of 11 to a theme issue 'Dissipation and heating in solar wind turbulence' . A review of spectral anisotropy and variance anisotropy for solar wind fluctuations is given, with the discussion covering inertial range and dissipation range scales. For the inertial range, theory, simulations and observations are more or less in accord, in that fluctuation energy is found to be primarily in modes with quasi-perpendicular wavevectors (relative to a suitably defined mean magnetic field), and also that most of the fluctuation energy is in the vector components transverse to the mean field. Energy transfer in the parallel direction and the energy levels in the parallel components are both relatively weak. In the dissipation range, observations indicate that variance anisotropy tends to decrease towards isotropic levels as the electron gyroradius is approached; spectral anisotropy results are mixed. Evidence for and against wave interpretations and turbulence interpretations of these features will be discussed. We also present new simulation results concerning evolution of variance anisotropy for different classes of initial conditions, each with typical background solar wind parameters.

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Section: (A) Review Of Observationsmentioning

confidence: 48%

Anisotropy in solar wind plasma turbulence

Oughton

Matthaeus

Wan

et al. 2015

Phil. Trans. R. Soc. A.

128

113

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“…This represents that the large-angle current sheets may originate from a different mechanism from the small-angle population. The first approximate log-normal distribution is similar to the result of Miao, Peng, and Li (2011); this result shows that there are perhaps small-angle current sheets that developed in the solar-wind MHD turbulence, as shown by Zhou, Matthaeus, and Dmitruk (2004) and Chang, Tam, and Wu (2004). Therefore, these current sheets may represent the intrinsic intermittency of the solar-wind MHD turbulence.…”

supporting

confidence: 57%

“…For example, numerical MHD simulations by Zhou, Matthaeus, and Dmitruk (2004) and Chang, Tam, and Wu (2004) showed that current sheets can emerge from the dynamical evolution of the nonlinear interactions of the solar-wind MHD turbulence. All of these studies suggested that the current sheet is an intrinsic property of the solar-wind MHD turbulence.…”

Section: Introductionmentioning

confidence: 99%

Tracking Back the Solar Wind to Its Photospheric Footpoints from Wind Observations – A Statistical Study

Huang¹,

Yan²,

Li³

et al. 2014

Coronal Magnetometry

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It is of great importance to track the solar wind back to its photospheric source region and identify the related current sheets; this will provide key information for investigating the origin and predictions of the solar wind. We report a statistical study relating the photospheric footpoint motion and in-situ observation of current sheets in the solar wind. We used the potential force-free source-surface (PFSS) model and the daily synoptic charts to trace the solar wind back from 1 AU, as observed by the Wind spacecraft, to the solar surface. As the footpoints move along the solar surface we obtain a time series of the jump times between different points. These jumps can be within a cell and between adjacent cells. We obtained the distribution of the jump times and the distribution for a subset of the jump times in which only jumps between adjacent cells were counted. For both cases, the distributions clearly show two populations. These distributions are compared with the distribution of in-situ current sheets reported in an earlier work of Miao, Peng, and Li ( Ann. Geophys. 29, 237, 2011). Its implications on the origin of the current sheets are discussed.

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“…A naive modeling is W + 2 Z − /l, where l is the characteristic length scale of the wave-like component. In fact, a multiplicative factor should be included to account for the shortening of the triple correlation time scale (see equation (A4)) associated with the wave-like propagation effects for this nonlinear term [Kraichnan, 1965;Grappin et al, 1982Grappin et al, , 1983Matthaeus and Zhou, 1989;Zhou et al, 2004]. Generically, these factors are G = (1 + t nl /t A ) −1 < 1, so that for this example term our modeling yields G z zw W + 2 Z − /l.…”

Section: Incompressible Two-component Turbulence Modelmentioning

confidence: 99%

Transport of solar wind fluctuations: A two-component model

et al. 2011

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[1] We present a new model for the transport of solar wind fluctuations which treats them as two interacting incompressible components: quasi-two-dimensional turbulence and a wave-like piece. Quantities solved for include the energy, cross helicity, and characteristic transverse length scale of each component, plus the proton temperature. The development of the model is outlined and numerical solutions are compared with spacecraft observations. Compared to previous single-component models, this new model incorporates a more physically realistic treatment of fluctuations induced by pickup ions and yields improved agreement with observed values of the correlation length, while maintaining good observational accord with the energy, cross helicity, and temperature.

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Colloquium: Magnetohydrodynamic turbulence and time scales in astrophysical and space plasmas

Cited by 235 publications

References 96 publications

Anisotropy in solar wind plasma turbulence

Anisotropy in solar wind plasma turbulence

Tracking Back the Solar Wind to Its Photospheric Footpoints from Wind Observations – A Statistical Study

Transport of solar wind fluctuations: A two-component model

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