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The phenomenology of velocity statistics in turbulent flows, up to now, relates to different models dealing with either signed or unsigned longitudinal velocity increments, with either inertial or dissipative fluctuations. In this paper, we…

Statistical Mechanics · Physics 2007-05-23 L. Chevillard , B. Castaing , E. Leveque , A. Arneodo

We study properties of dilute polymer solutions which are known to depend strongly on polymer elongation. The probability density function (PDF) of polymer end-to-end extensions $R$ in turbulent flows is examined. We demonstrate that if the…

chao-dyn · Physics 2009-10-31 E. Balkovsky , A. Fouxon , V. Lebedev

In star-forming clouds, high velocity flow gives rise to large fluctuations of density. In this work we explore the correlation between velocity magnitude (speed) and density. We develop an analytic formula for the joint probability…

Astrophysics of Galaxies · Physics 2023-08-02 Branislav Rabatin , David C. Collins

The rich structure that we observe in molecular clouds is due to the interplay between strong magnetic fields and supersonic (turbulent) velocity fluctuations. The velocity fluctuations interact with the magnetic field, causing it too to…

Astrophysics of Galaxies · Physics 2020-08-12 James R. Beattie , Christoph Federrath , Amit Seta

We have discovered analytical expressions for the probability density function (PDF) of photons that are multiply scattered in relativistic flows, under the assumption of isotropic and inelastic scattering. These expressions characterize…

We derive the sampling probability density function (pdf) of an ideal localized random electromagnetic field, its amplitude and intensity in an electromagnetic environment that is quasi-statically time-varying statistically homogeneous or…

Mesoscale and Nanoscale Physics · Physics 2015-05-13 L. R. Arnaut

This letter provides the first prediction of the probability density function (PDF) of flux $R$ in plasma sheath sheath region in magnetic fusion devices which is characterized by dynamical equations with exponential non-linearities. By…

Plasma Physics · Physics 2015-05-13 Johan Anderson , Eun-jin Kim

High Reynolds number isotropic magneto-hydro-dynamic turbulence in the presence of large scale magnetic fields is investigated as a function of the magnetic field strength. For a variety of flow configurations the energy dissipation rate…

Fluid Dynamics · Physics 2012-09-20 Alexandros Alexakis

We derive a first order linear differential equation describing the shape of the probability density function of magnetic field strengths in the quiet Sun (PDF). The modeling is very schematic. It considers convective motions which…

Astrophysics · Physics 2008-11-26 J. Sanchez Almeida

We used magnetohydrodynamic (MHD) simulations of interstellar turbulence to study the probability distribution functions (PDFs) of increments of density, velocity, and magnetic field. We found that the PDFs are well described by a Tsallis…

Astrophysics of Galaxies · Physics 2011-08-04 A. Esquivel , A. Lazarian

Mathematical models based on probability density functions (PDF) have been extensively used in hydrology and subsurface flow problems, to describe the uncertainty in porous media properties (e.g., permeability modelled as random field).…

Fluid Dynamics · Physics 2020-06-01 Matteo Icardi , Marco Dentz

Both observational and theoretical research over the past decade has demonstrated that the probability distribution function (PDF) of the gas density in turbulent molecular clouds is a key ingredient for understanding star formation. It has…

Astrophysics of Galaxies · Physics 2018-11-28 Bastian Körtgen , Christoph Federrath , Robi Banerjee

(Abridged) We discuss the probability distribution function (PDF) of column density resulting from density fields with lognormal PDFs, applicable to isothermal gas (e.g., probably molecular clouds). We suggest that a ``decorrelation…

Astrophysics · Physics 2009-11-06 Enrique Vazquez-Semadeni , Nieves Garcia

The probability density function (PDF) of accelerations in turbulence is derived analytically with the help of the multifractal analysis based on generalized entropy, i.e., the Tsallis or the R\'{e}nyi entropy. It is shown that the derived…

Statistical Mechanics · Physics 2007-05-23 T. Arimitsu , N. Arimitsu

Plasma density fluctuations in the edge plasma of the RFX-mod device are measured through the Gas Puffing Imaging Diagnostics. Statistical features of the signal are quantified in terms of the Probability Distribution Function (PDF), and…

Plasma Physics · Physics 2007-05-23 F. Sattin , P. Scarin , M. Agostini , R. Cavazzana , G. Serianni , M. Spolaore , N. Vianello

We present a systematic numerical study of the effect of turbulent velocity fluctuations on the thermal pressure distribution in thermally bistable flows. The simulations employ a random turbulent driving generated in Fourier space rather…

Astrophysics · Physics 2009-11-11 Adriana Gazol , Enrique Vazquez-Semadeni , Jongsoo Kim

The probability distribution function (PDF) tails of the zonal flow structure formation and the PDF tails of momentum flux by incorporating effect of a shear flow in ion-temperature-gradient (ITG) turbulence are computed in the present…

Plasma Physics · Physics 2009-11-13 Johan Anderson , Eun-jin Kim

Recent measurements of solar wind turbulence report the presence of intermittent, exponentially distributed angular discontinuities in the magnetic field. In this Letter, we study whether such discontinuities can be produced by…

Solar and Stellar Astrophysics · Physics 2012-10-15 Vladimir Zhdankin , Stanislav Boldyrev , Joanne Mason , Jean Carlos Perez

The topological and dynamical features of small scales are studied in the context of decaying magnetohydrodynamic turbulent flows using direct numerical simulations. Joint probability density functions (PDFs) of the invariants of gradient…

Fluid Dynamics · Physics 2015-06-15 Vassilios Dallas , Alexandros Alexakis

We present numerical simulations of an isothermal turbulent gas undergoing gravitational collapse, aimed at testing for ``logatropic'' behavior of the form $P_t \sim \log \rho$, where $P_t$ is the ``turbulent pressure'' and $\rho$ is the…

Astrophysics · Physics 2009-10-30 E. Vazquez-Semadeni , J. Canto , S. Lizano