English
Related papers

Related papers: Mean-field dynamo as a quantumlike modulational in…

200 papers

We analyze 3D numerical simulations of driven incompressible magnetohydrodynamic (MHD) turbulence in a periodic box threaded by a moderately strong external magnetic field. We sum over nonlinear interactions within Fourier wavebands and…

Astrophysics · Physics 2011-05-10 Jungyeon Cho , Alex Lazarian , Ethan Vishniac

Turbulence simulations play a key role in advancing the general understanding of the physical properties turbulence and in interpreting astrophysical observations of turbulent plasmas. For the sake of simplicity, however, turbulence…

Astrophysics of Galaxies · Physics 2020-02-05 Philipp Grete , Brian W. O'Shea , Kris Beckwith

Magnetic fields are ubiquitous in the interstellar medium, including extended objects such as supernova remnants and diffuse halos around Pulsars. Its turbulent characteristics govern the diffusion of cosmic rays and the multi-wavelength…

High Energy Astrophysical Phenomena · Physics 2024-03-21 Sunil Malik , Ka Ho Yuen , Huirong Yan

The field line random walk (FLRW) of magnetic turbulence is one of the important topics in plasma physics and astrophysics. In this article by using the field line tracing method mean square displacements (MSD) of FLRW is calculated in all…

High Energy Astrophysical Phenomena · Physics 2017-09-13 J. F. Wang , G. Qin , Q. M. Ma , T. Song , S. B. Yuan

We study the asymptotic properties of a stochastic model for the induction equations of the magnetic field in a three dimensional periodic domain. The turbulent velocity field driving the electromotive force on the magnetic field is modeled…

Probability · Mathematics 2025-06-04 Federico Butori , Eliseo Luongo

Helical turbulence is thought to provide the key to the generation of large-scale magnetic fields. Turbulence also generically leads to rapidly growing small-scale magnetic fields correlated on the turbulence scales. These two processes are…

Astrophysics · Physics 2008-11-26 Kandaswamy Subramanian

Recent numerical and observational studies revealed that spectra of magnetic and velocity fluctuations in MHD turbulence have different scaling indexes. This intriguing feature has been recently explained in the case of weak MHD turbulence,…

Astrophysics of Galaxies · Physics 2012-02-17 Stanislav Boldyrev , Jean Carlos Perez , Yuxuan Wang

We establish a new theoretical framework, based on a time-dependent mean field approach, to address the dynamics of the driven Dicke model. The joint evolution of both mean fields and quantum fluctuations gives rise to a rich and generally…

Quantum Physics · Physics 2016-08-18 G. Francica , S. Montangero , M. Paternostro , F. Plastina

It is shown that magnetic islands generated by pressure-gradient-driven turbulence are common across a wide range of conditions. The interaction among turbulence, magnetic island and other large scale structures (the zonal flow and the…

Plasma Physics · Physics 2025-07-01 Daniele Villa , Nicolas Dubuit , Olivier Agullo , Xavier Garbet

A new simple dynamo model for stellar activity cycle is proposed. By considering an inhomogeneous mean flow effect on turbulence, it is shown that turbulent cross helicity (velocity--magnetic-field correlation) should enter the expression…

Solar and Stellar Astrophysics · Physics 2016-06-22 Nobumitsu Yokoi , Dieter Schmitt , Valery Pipin , Fujihiro Hamba

A key uncertainty in the design and development of magnetic confinement fusion energy reactors is predicting edge plasma turbulence. An essential step in overcoming this uncertainty is the validation in accuracy of reduced turbulent…

Plasma Physics · Physics 2022-05-20 Abhilash Mathews , Noah Mandell , Manaure Francisquez , Jerry Hughes , Ammar Hakim

Mean-field galactic dynamo theory is the leading theory to explain the prevalence of regular magnetic fields in spiral galaxies, but its systematic comparison with observations is still incomplete and fragmentary. Here we compare…

Astrophysics of Galaxies · Physics 2016-12-14 Luke Chamandy , Anvar Shukurov , A. Russ Taylor

A mean-field theory of the electrodynamics of a turbulent fluid is formulated under the assumption that the molecular electric conductivity is correlated with the turbulent velocity fluctuation in the (radial) direction, $\mathbf{g}$. It is…

Fluid Dynamics · Physics 2023-05-03 Oliver Gressel , Günther Rüdiger , Detlef Elstner

To explain the large-scale magnetic field of the Sun and other bodies, mean-field dynamo theory is commonly applied where one solves the averaged equations for the mean magnetic field. However, the standard approach breaks down when the…

Solar and Stellar Astrophysics · Physics 2018-06-06 A. Brandenburg , P. Chatterjee

Using the test-field method for nearly irrotational turbulence driven by spherical expansion waves it is shown that the turbulent magnetic diffusivity increases with magnetic Reynolds numbers. Its value levels off at several times the rms…

Astrophysics of Galaxies · Physics 2010-11-05 Axel Brandenburg , Fabio Del Sordo

[ABRIDGED] This paper discusses the importance of parallel perturbations of the magnetic-field in gyrokinetic simulations of electromagnetic instabilities and turbulence at mid-radius in the burning plasma phase of the conceptual…

A weak turbulence theory is derived for magnetohydrodynamics under rapid rotation and in the presence of a large-scale magnetic field. The angular velocity $\Omega_0$ is assumed to be uniform and parallel to the constant Alfv\'en speed…

Geophysics · Physics 2015-06-19 Sebastien Galtier

We study compressible MHD turbulence, which holds key to many astrophysical processes, including star formation and cosmic ray propagation. To account for the variations of the magnetic field in the strongly turbulent fluid we use wavelet…

Astrophysics of Galaxies · Physics 2015-05-18 Grzegorz Kowal , Alex Lazarian

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…

An exact analogy of electromagnetic fields and particles can be found in continuum mechanics of a turbulent perfect fluid with voids. Deviations of the turbulence from a homogeneous isotropic state correspond to electromagnetic fields: with…

General Physics · Physics 2022-03-02 Valery P. Dmitriyev