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Related papers: Magnetic dynamo action in astrophysical turbulence

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Magnetic turbulence is classified as weak or strong based on the relative amplitude of the magnetic field fluctuations compared to the mean field. These two classifications have different energy transport properties. This study analyzes…

Astrophysics of Galaxies · Physics 2024-11-13 Evangelia Ntormousi , Loukas Vlahos , Anna Konstantinou , Heinz Isliker

We investigate the energy pathways between the velocity and the magnetic fields in a rotating plane layer dynamo driven by Rayleigh-B\'enard convection using direct numerical simulations. The kinetic and magnetic energies are divided into…

Fluid Dynamics · Physics 2022-12-20 Souvik Naskar , Anikesh Pal

The origin of strong magnetic fields in the Universe can be explained by amplifying weak seed fields via turbulent motions on small spatial scales and subsequently transporting the magnetic energy to larger scales. This process is known as…

In stars and planets, magnetic fields are believed to originate from the motion of electrically conducting fluids in their interior, through a process known as the dynamo mechanism. In this Letter, an optimization procedure is used to…

Fluid Dynamics · Physics 2015-03-20 Ashley P. Willis

The diffusion of astrophysical magnetic fields in conducting fluids in the presence of turbulence depends on whether magnetic fields can change their topology via reconnection in highly conducting media. Recent progress in understanding…

Astrophysics of Galaxies · Physics 2012-12-17 R. Santos-Lima , A. Lazarian , E. M. de Gouveia Dal Pino , J. Cho

We derive a new shell model of magnetohydrodynamic (MHD) turbulence in which the energy transfers are not necessary local. Like the original MHD equations, the model conserves the total energy, magnetic helicity, cross-helicity and volume…

Fluid Dynamics · Physics 2009-09-29 F. Plunian , R. Stepanov

The influence of fluctuating conductivity on the coefficients known from the mean-field electrodynamics is considered. If the conductivity fluctuations are assumed as uncorrelated with the turbulent velocity field then only the effective…

Plasma Physics · Physics 2020-07-15 G. Rüdiger , M. Küker , P. J. Käpylä

Context: During the last decades, significant progress has been made in both numerical simulations of turbulent dynamo and theoretical understanding of turbulence. However, there is still lack of quantitative comparison between the…

Fluid Dynamics · Physics 2026-04-08 A. V. Kopyev , A. S. Il'yn , V. A. Sirota , K. P. Zybin

A weak fluctuating magnetic field embedded into a turbulent conducting medium grows exponentially while its characteristic scale decays. In the ISM and protogalactic plasmas, the magnetic Pr is very large, so a broad spectrum of growing…

Astrophysics · Physics 2008-11-26 Alexander Schekochihin , Steven Cowley , Jason Maron , Leonid Malyshkin

We analyze the dynamics of a charged particle moving in the presence of spatially-modulated magnetic fields. From Poincare surfaces of section and Liapunov exponents for characteristic trajectories we find that the fraction of pinned and…

Mesoscale and Nanoscale Physics · Physics 2009-10-31 Esmael Badran , Sergio E. Ulloa

We use direct and stochastic numerical simulations of the magnetohydrodynamic equations to explore the influence of turbulence on the dynamo threshold. In the spirit of the Kraichnan-Kazantsev model, we model the turbulence by a noise, with…

We study a nonlinear quenching of turbulent magnetic diffusion and effective drift velocity of large-scale magnetic field in a developed two-dimensional MHD turbulence at large magnetic Reynolds numbers. We show that transport of the…

Astrophysics · Physics 2009-06-23 N. Kleeorin , I. Rogachevskii

Turbulence and dynamo induced by the magnetorotational instability (MRI) are analyzed using quasi-linear statistical simulation methods. It is found that homogenous turbulence is unstable to a large scale dynamo instability, which saturates…

High Energy Astrophysical Phenomena · Physics 2015-06-01 Jonathan Squire , Amitava Bhattacharjee

The extent to which large scale magnetic fields are susceptible to turbulent diffusion is important for interpreting the need for in situ large scale dynamos in astrophysics and for observationally inferring field strengths compared to…

Cosmology and Nongalactic Astrophysics · Physics 2015-11-18 Eric G. Blackman , Kandaswamy Subramanian

Large-scale magnetic fields thread through the electrically conducting matter of the interplanetary and interstellar medium, stellar interiors, and other astrophysical plasmas, producing anisotropic flows with regions of…

Fluid Dynamics · Physics 2022-07-13 J. Pratt , A. Busse , W. -C. Müller

Dynamo action refers to energy exchange processes through which magnetic fields are generated at the expense of kinetic energy of the plasma flows. Dynamos can generate magnetic fields across scales larger or smaller than the flows…

The dynamics of the two-dimensional (2D) state in driven tridimensional (3D) incompressible magnetohydrodynamic turbulence is investigated through high-resolution direct numerical simulations and in the presence of an external magnetic…

Solar and Stellar Astrophysics · Physics 2015-05-19 Barbara Bigot , Sebastien Galtier

In this review article we will describe recent developments in statistical theory of magnetohydrodynamic (MHD) turbulence. Kraichnan and Iroshnikov first proposed a phenomenology of MHD turbulence where Alfven time-scale dominates the…

Chaotic Dynamics · Physics 2009-11-10 Mahendra K. Verma

The magnetic field of planets or stars is generated by the motion of a conducting fluid through a dynamo instability. The saturation of the magnetic field occurs through the reaction of the Lorentz force on the flow. In relation to this…

Fluid Dynamics · Physics 2009-11-13 Michael Berhanu , Basile Gallet , Nicolas Mordant , Stephan Fauve

The modelling of astrophysical systems such as binary neutron star mergers or the formation of magnetars from the collapse of massive stars involves the numerical evolution of magnetised fluids at extremely large Reynolds numbers. This is a…

High Energy Astrophysical Phenomena · Physics 2023-10-20 Miquel Miravet-Tenés , Pablo Cerdá-Durán , Martin Obergaulinger , José A. Font
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