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This paper presents the numerical verification of an asymptotic analytical solution for the nonlinear interaction between counterpropagating Alfven waves, the fundamental building block of astrophysical plasma turbulence. The analytical…

Solar and Stellar Astrophysics · Physics 2015-06-16 Kevin D. Nielson , Gregory G. Howes , William Dorland

We present numerical simulations and explore scalings and anisotropy of compressible magnetohydrodynamic (MHD) turbulence. Our study covers both gas pressure dominated (high beta) and magnetically dominated (low beta) plasmas at different…

Astrophysics · Physics 2011-05-05 Jungyeon Cho , A. Lazarian

An asymptotic limit of a class of Cahn-Hilliard systems is investigated to obtain a general nonlinear diffusion equation. The target diffusion equation may reproduce a number of well-known model equations: Stefan problem, porous media…

Analysis of PDEs · Mathematics 2015-12-01 Pierluigi Colli , Takeshi Fukao

Reduced fluid models including electron inertia and ion finite Larmor radius corrections are derived asymptotically, both from fluid basic equations and from a gyrofluid model. They apply to collisionless plasmas with small ion-to-electron…

Plasma Physics · Physics 2022-02-02 Thierry Passot , Pierre-Louis Sulem , Emanuele Tassi

The spatial diffusion of cosmic rays in turbulent magnetic fields can, in the most general case, be fully anisotropic, i.e. one has to distinguish three diffusion axes in a local, field-aligned frame. We reexamine the transformation for the…

Following a general heuristic approach, algebraic constraints are established between the parallel and perpendicular power-law exponents of non-axisymmetric, highly aligned magnetohydrodynamic turbulence, both with and without strong…

Plasma Physics · Physics 2025-04-28 Ramesh Sasmal , Supratik Banerjee

Quasilinear perpendicular diffusion of charged particles in fluctuating electromagnetic fields is the focus of this paper. A general transport parameter for perpendicular diffusion is presented being valid for an arbitrary turbulence…

Astrophysics · Physics 2007-05-23 O. Stawicki

We investigate the influence of a uniform magnetic field ${\bf B_0}=B_0 e//$ on energy decay laws in incompressible magnetohydrodynamic (MHD) turbulence. The nonlinear transfer reduction along $B_0$ is included in a model that distinguishes…

Fluid Dynamics · Physics 2009-11-13 Barbara Bigot , Sebastien Galtier , Helene Politano

A fourth-order and a second-order nonlinear diffusion models in spectral space are proposed to describe gravitational wave turbulence in the approximation of strongly local interactions. We show analytically that the model equations satisfy…

General Relativity and Quantum Cosmology · Physics 2019-03-27 Sébastien Galtier , Sergey V. Nazarenko , Éric Buchlin , Simon Thalabard

The nonlinear interaction between counterpropagating Alfven waves is the physical mechanism underlying the cascade of energy to small scales in astrophysical plasma turbulence. Beginning with the equations for incompressible MHD, an…

Solar and Stellar Astrophysics · Physics 2015-06-16 Gregory G. Howes , Kevin D. Nielson

A non-perturbative nonlinear statistical approach is presented to describe turbulent magnetic systems embedded in a uniform mean magnetic field. A general formula in the form of an ordinary differential equation for magnetic field-line…

Astrophysics · Physics 2009-11-13 A. Shalchi , I. Kourakis

By using the quantum hydrodynamic and Maxwell equations, we derive nonlinear electron-magnetohydrodynamic (MHD), Hall-MHD, and dust Hall-MHD equations for dense quantum magnetoplasmas. The nonlinear equations include the electromagnetic,…

Plasma Physics · Physics 2015-05-13 N. Shukla , G. Brodin , M. Marklund , P. K. Shukla , L. Stenflo

A relativistic bounce-averaged quasilinear diffusion equation is derived to describe stochastic particle transport associated with arbitrary-frequency electromagnetic fluctuations in a nonuniform magnetized plasma. Expressions for the…

Space Physics · Physics 2009-11-10 Alain J. Brizard , Anthony A. Chan

We use the 3D fully kinetic simulation to study different turbulence modes and turbulence anisotropy of relativistic turbulence in magnetically dominated collisionless plasmas. We extend the method developed by Cho & Lazarian (2002) for…

Plasma Physics · Physics 2026-04-24 Samuel T. Sebastian , Siyao Xu , Yue Hu , Luca Comisso , Saikat Das , Joonas Nättilä

Turbulence in astrophysical and space plasmas is dominated by the nonlinear interaction of counterpropagating Alfven waves. Most Alfven wave turbulence theories have been based on ideal plasma models, such as incompressible MHD, for Alfven…

Anisotropy of MHD turbulence has been studied extensively for many years, most prominently by measurements in the solar wind and high resolution simulations. The spectrum parallel to the local magnetic field was observed to be steeper than…

Solar and Stellar Astrophysics · Physics 2015-06-22 Andrey Beresnyak

Stochasticity of magnetic field lines is important for particle transport properties. Magnetic field lines separate faster than diffusively in turbulent plasma, which is called superdiffusion. We discovered that this superdiffusion is…

High Energy Astrophysical Phenomena · Physics 2015-06-15 Andrey Beresnyak

We have extended our previous mean-field galactic dynamo model which included algebraic and dynamic alpha nonlinearities (Kleeorin et al., A&A, v. 387, 453, 2002), to include also a quenching of turbulent diffusivity. We readily obtain…

Astrophysics · Physics 2014-10-13 N. Kleeorin , D. Moss , I. Rogachevskii , D. Sokoloff

Anisotropic Alfv\'{e}nic fluctuations with $k_{\parallel}/k_{\perp}\ll 1$ remain at frequencies much smaller than the ion cyclotron frequency in the presence of a strong background magnetic field. Based on the simplest truncation of the…

Solar and Stellar Astrophysics · Physics 2015-05-19 N. H. Bian , E. P. Kontar

The nonlinear theory of driven magnetohydrodynamics (MHD) waves in strongly anisotropic and dispersive plasmas, developed for slow resonance by Clack and Ballai [Phys. Plasmas, 15, 2310 (2008)] and Alfv\'en resonance by Clack \emph{et al.}…

Solar and Stellar Astrophysics · Physics 2014-11-18 C. Clack , I. Ballai