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Related papers: Self-similar turbulent dynamo

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The emergence of large-scale magnetic fields observed in the diffuse interstellar medium is explained by a turbulent dynamo. The underlying transport coefficients have previously been extracted from numerical simulations. So far, this was…

Astrophysics of Galaxies · Physics 2015-06-11 Oliver Gressel , Abhijit Bendre , Detlef Elstner

Particle acceleration and magnetic field amplification in relativistic shocks propagating in inhomogeneous media are investigated by three-dimensional magnetohydrodynamical (MHD) simulations and test-particle simulations. The MHD…

High Energy Astrophysical Phenomena · Physics 2024-06-27 Kanji Morikawa , Yutaka Ohira , Takumi Ohmura

The amplification of a magnetic field due to the Richtmyer-Meshkov instability (RMI) is investigated by two-dimensional MHD simulations. Single-mode analysis is adopted to reveal definite relation between the nonlinear evolution of RMI and…

High Energy Astrophysical Phenomena · Physics 2015-06-11 Takayoshi Sano , Katsunobu Nishihara , Chihiro Matsuoka , Tsuyoshi Inoue

We report an experimental investigation on the influence of an external magnetic field on forced 3D turbulence of liquid gallium in a closed vessel. We observe an exponential damping of the turbulent velocity fluctuations as a function of…

Fluid Dynamics · Physics 2015-05-14 Basile Gallet , Michael Berhanu , Nicolas Mordant

The mean-field theory of magnetized stellar convection gives rise to the two possibility of distinct instabilities: the large-scale dynamo instability, operating in the bulk of the convection zone, and a negative effective magnetic pressure…

Solar and Stellar Astrophysics · Physics 2014-11-03 Sarah Jabbari , Axel Brandenburg , Illa R. Losada , Nathan Kleeorin , Igor Rogachevskii

We have tested the ability of driven turbulence to generate magnetic field structure from a weak uniform field using three dimensional numerical simulations of incompressible turbulence. We used a pseudo-spectral code with a numerical…

Astrophysics · Physics 2009-10-31 Jungyeon Cho , Ethan T. Vishniac

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

The amplification and maintenance of the observed magnetic fields in the ICM are usually attributed to the turbulent dynamo action. This is generally derived employing a collisional MHD model. However, in the ICM the ion mean free path…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-16 R. Santos-Lima , E. M. de Gouveia Dal Pino , G. Kowal , D. Falceta-Gonçalves , A. Lazarian , M. S. Nakwacki

The conventional theory of small-scale magnetic field generation in a turbulent flow considers time-reversible random flows. However, real turbulent flows are known to be time irreversible: the presence of energy cascade is an intrinsic…

Fluid Dynamics · Physics 2023-12-20 A. V. Kopyev , A. S. Il'yn , V. A. Sirota , K. P. Zybin

Fast particles diffusing along magnetic field lines in a turbulent plasma can diffuse through and then return to the same eddy many times before the eddy is randomized in the turbulent flow. This leads to an enhancement of particle…

Astrophysics · Physics 2009-11-10 Benjamin D. G. Chandran , Jason L. Maron

Magnetic fields grow quickly even at early cosmological times, suggesting the action of a small-scale dynamo (SSD) in the interstellar medium of galaxies. Many studies have focused on idealized turbulent driving of the SSD. Here we simulate…

Astrophysics of Galaxies · Physics 2021-04-07 Frederick A. Gent , Mordecai-Mark Mac Low , Maarit J. Kapyla , Nishant K. Singh

We consider a two-dimensional athermal binary mixture of Lennard-Jones particles with persistent random active forces. The liquid phase of this system for active forces exceeding a threshold value exhibits self-organization with long-range…

Soft Condensed Matter · Physics 2025-12-24 Atharva Shukla , Chandan Dasgupta

The mechanisms that generate "seed" magnetic fields in our Universe and that amplify them throughout cosmic time remain poorly understood. By means of fully-kinetic particle-in-cell simulations of turbulent, initially unmagnetized plasmas,…

Cosmology and Nongalactic Astrophysics · Physics 2023-08-09 L. Sironi , L. Comisso , R. Golant

Using direct numerical simulations of the equations of magnetohydrodynamics, we study reversals of the magnetic field generated by the flow of an electrically conducting fluid in a sphere. We show that at low magnetic Prandtl numbers,…

Fluid Dynamics · Physics 2015-06-17 Pankaj Mishra , Christophe Gissinger , Emmanuel Dormy , Stephan Fauve

Context. Earlier work has suggested that large-scale dynamos can reach and maintain equipartition field strengths on a dynamical time scale only if magnetic helicity of the fluctuating field can be shed from the domain through open…

Solar and Stellar Astrophysics · Physics 2011-07-08 P. J. Käpylä , M. J. Korpi , A. Brandenburg

Simulations of the magnetorotational instability (MRI) in a homogeneous shearing box have shown that the asymptotic strength of the magnetic field declines steeply with increasing resolution. Here I model the MRI driven dynamo as a large…

High Energy Astrophysical Phenomena · Physics 2011-02-11 Ethan T. Vishniac

The emergence of a large scale magnetic field from randomly forced isotropic strongly helical flows is discussed in terms of the inverse cascade of magnetic helicity and the alpha-effect. In simulations of such flows the maximum field…

Astrophysics · Physics 2007-05-23 Axel Brandenburg

A magnetic field rotating on the free surface of a ferrofluid layer is shown to induce considerable fluid motion toward the direction the field is rolling. The measured flow velocity i) increases with the square of the magnetic field…

Fluid Dynamics · Physics 2007-05-23 Robert Krauss , Mario Liu , Bert Reimann , Reinhard Richter , Ingo Rehberg

We discuss magnetic pressure and density fluctuations in strongly turbulent isothermal MHD flows in "1+2/3" dimensions. We first consider "simple" nonlinear MHD waves, which allow us show that the slow and fast modes have different…

Astrophysics · Physics 2007-05-23 Thierry Passot , Enrique Vazquez-Semadeni

We present preliminary results from high resolution magneto-convection simulations where we find the formation of flux concentrations from an initially uniform magnetic field. We compute the effective magnetic pressure but find that the…

Solar and Stellar Astrophysics · Physics 2015-12-16 P. J. Käpylä , A. Brandenburg , N. Kleeorin , M. J. Mantere , I. Rogachevskii
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