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Related papers: The Nonlinear Turbulent Dynamo

200 papers

This is a brief review of the main results of our recent studies of the nonlinear evolution of the small-scale MHD dynamo in the high-Prandtl-number regime and of the structure of the resulting saturated state of the isotropic homogeneous…

Astrophysics · Physics 2007-05-23 A. A. Schekochihin , S. C. Cowley , G. W. Hammett , J. L. Maron , J. C. McWilliams

The turbulent dynamo is a powerful mechanism that converts turbulent kinetic energy to magnetic energy. A key question regarding the magnetic field amplification by turbulence, is, on what scale, $k_{\rm p}$, do magnetic fields become most…

Solar and Stellar Astrophysics · Physics 2022-04-08 Neco Kriel , James R. Beattie , Amit Seta , Christoph Federrath

The question of whether a dynamo can be triggered by gravitational collapse is of great interest, especially for the early Universe. Here, we employ supercomoving coordinates to study the magnetic field amplification from decaying…

Astrophysics of Galaxies · Physics 2025-09-11 Axel Brandenburg , Evangelia Ntormousi

We present results from numerical simulations of nonlinear MHD dynamo action produced by three-dimensional flows that become turbulent for high values of the fluid Reynolds number. The magnitude of the forcing function driving the flow is…

Astrophysics · Physics 2009-11-07 Vasilis Archontis , Bertil Dorch , Aake Nordlund

We explore the amplification of magnetic fields in the high-redshift Universe. For this purpose, we perform high-resolution cosmological simulations following the formation of primordial halos with \sim10^7 M_solar, revealing the presence…

We investigate the Lagrangian mechanism of the kinematic ``fluctuation'' magnetic dynamo in turbulent plasma flow at small magnetic Prandtl numbers. The combined effect of turbulent advection and plasma resistivity is to carry infinitely…

Plasma Physics · Physics 2015-05-13 Gregory L. Eyink , Antonio F. Neto

We study the evolution of magnetic fields in turbulent hot plasma of the early Universe accounting for the chiral magnetic effect. The magnetohydrodynamic turbulence is modeled by replacing the matter velocity in the advection term in the…

Cosmology and Nongalactic Astrophysics · Physics 2018-01-17 Maxim Dvornikov

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

The flow of an electrically conducting fluid in a thin disc under the action of an azimuthal Lorentz force is studied experimentally. At small forcing, the Lorentz force is balanced by either viscosity or inertia, yielding quasi-Keplerian…

Fluid Dynamics · Physics 2021-09-14 Marlone Vernet , Michael Pereira , Stephan Fauve , Christophe Gissinger

The existence of a weak galactic magnetic field has been repeatedly confirmed by observational data. The origin of this field has not as yet been explained in a fully satisfactory way and represents one of the main challenges of the…

Astrophysics · Physics 2009-11-06 Alexander Schekochihin , Stanislav Boldyrev , Russell Kulsrud

We present results from particle-in-cell simulations of driven turbulence in magnetized, collisionless, and relativistic pair plasma. We find that fluctuations are consistent with the classical $k_\perp^{-5/3}$ magnetic energy spectrum at…

Plasma Physics · Physics 2017-02-14 Vladimir Zhdankin , Gregory R. Werner , Dmitri A. Uzdensky , Mitchell C. Begelman

We perform two-dimensional relativistic magnetohydrodynamic simulations of a mildly relativistic shock propagating through an inhomogeneous medium. We show that the postshock region becomes turbulent owing to preshock density inhomogeneity,…

High Energy Astrophysical Phenomena · Physics 2015-05-20 Yosuke Mizuno , Martin Pohl , Jacek Niemiec , Bing Zhang , Ken-Ichi Nishikawa , Philip E. Hardee

The small-scale dynamo is typically studied by assuming that the correlation time of the velocity field is zero. Some authors have used a smooth renovating flow model to study how the properties of the dynamo are affected by the correlation…

Astrophysics of Galaxies · Physics 2024-05-01 Kishore Gopalakrishnan , Nishant K Singh

(abridged) Context: Turbulent diffusion of large-scale flows and magnetic fields play major roles in many astrophysical systems. Aims: Our goal is to compute turbulent viscosity and magnetic diffusivity, relevant for diffusing large-scale…

Solar and Stellar Astrophysics · Physics 2020-04-29 Petri J. Käpylä , Matthias Rheinhardt , Axel Brandenburg , Maarit J. Käpylä

We explore the effect of the magnetic Prandtl number Pm on energy and dissipation in fully resolved direct numerical simulations of steady-state, mechanically forced homogeneous magnetohydrodynamic turbulence in the range Pm = 1/32 to 32.…

Fluid Dynamics · Physics 2019-01-17 Mairi E. McKay , Arjun Berera , Richard D. J. G. Ho

The amplification of magnetic fields in a highly conducting fluid is studied numerically. During growth, the magnetic field is spatially intermittent: it does not uniformly fill the volume, but is concentrated in long thin folded…

Chaotic Dynamics · Physics 2009-11-10 A. A. Schekochihin , S. C. Cowley , J. L. Maron , J. C. McWilliams

Magnetized turbulence is ubiquitous in many astrophysical and terrestrial systems but no complete, uncontested theory even in the simplest form, magnetohydrodynamics (MHD), exists. Many theories and phenomenologies focus on the joint…

Plasma Physics · Physics 2021-03-24 Philipp Grete , Brian W. O'Shea , Kris Beckwith

Via amplification by turbulent dynamo, magnetic fields can be potentially important for the formation of the first stars. To examine the dynamo behavior during the gravitational collapse of primordial gas, we extend the theory of nonlinear…

Solar and Stellar Astrophysics · Physics 2020-08-26 Siyao Xu , Alex Lazarian

Small-scale dynamos (SSDs) amplify magnetic fields in turbulent plasmas. Theory predicts nonlinear magnetic energy growth $E_\mathrm{mag} \propto t^{p_\mathrm{nl}}$, but this scaling has not been tested across flow regimes. Using a large…

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