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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 dipole-multipole transition in rapidly rotating dynamos is investigated through the analysis of forced magnetohydrodynamic waves in an unstably stratified fluid. The focus of this study is on the inertia-free limit applicable to…

Fluid Dynamics · Physics 2023-09-25 Debarshi Majumder , Binod Sreenivasan , Gaurav Maurya

We consider fermionic dense matter under a magnetic field, where fermions couple minimally to gauge fields, and calculate anomalous currents at one loop. We find anomalous currents are spontaneously generated along the magnetic field but…

High Energy Physics - Theory · Physics 2011-06-16 Deog Ki Hong

Experimentally an asymmetry of the reversal modes has been found in certain exchange bias systems. From a numerical investigation of the domain state model evidence is gained that this effect depends on the angle between the easy axis of…

Condensed Matter · Physics 2009-11-10 B. Beckmann , U. Nowak , K. D. Usadel

The asymmetric shape of reversals of the Earth's magnetic field indicates a possible connection with relaxation oscillations as they were early discussed by van der Pol. A simple mean-field dynamo model with a spherically symmetric $\alpha$…

Geophysics · Physics 2009-05-20 Frank Stefani , Mingtian Xu , Luca Sorriso-Valvo , Gunter Gerbeth , Uwe Günther

In order to explore the magnetostrophic regime expected for planetary cores, experiments have been conducted in a rotating sphere filled with liquid sodium, with an imposed dipolar magnetic field (the DTS setup). The field is produced by a…

We analyze the initial, kinematic stage of magnetic field evolution in an isotropic and homogeneous turbulent conducting fluid with a rough velocity field, v(l) ~ l^alpha, alpha<1. We propose that in the limit of small magnetic Prandtl…

Astrophysics · Physics 2007-05-23 Stanislav Boldyrev , Fausto Cattaneo

We investigate the structure of magnetic field amplified by turbulent velocity fluctuations, in the framework of the kinematic Kazantsev-Kraichnan model. We consider Kolmogorov distribution of velocity fluctuations, and assume that both…

Astrophysics · Physics 2010-01-15 Leonid Malyshkin , Stanislav Boldyrev

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

This paper considers a possibility of magnetic-field generation by local turbulent flows at the bottom of convective zone. The cycle of magnetic-field generation in this model can be represented in the form of sequency of processes. There…

Solar and Stellar Astrophysics · Physics 2013-10-18 Andrey G. Tlatov

The main issue of the pulsar magnetosphere is how the rotation power is converted into both particle beams which causes pulsed emissions, and a highly relativistic wind of electron-positron plasmas which forms surrounding nebulae shining in…

High Energy Astrophysical Phenomena · Physics 2015-05-30 Tomohide Wada , Shinpei Shibata

Using simulations of helically driven turbulence, it is shown that the ratio of kinetic to magnetic energy dissipation scales with the magnetic Prandtl number in power law fashion with an exponent of approximately 0.6. Over six orders of…

Solar and Stellar Astrophysics · Physics 2011-05-16 A. Brandenburg

High-resolution observations with the Swedish 1-m Solar Telescope (SST) and the Solar Dynamics Observatory (SDO) reveal rotating magnetic field structures that extend from the solar surface into the chromosphere and the corona. These…

Solar and Stellar Astrophysics · Physics 2015-06-22 Sven Wedemeyer , Oskar Steiner

I present the numerical computation of speed and direction of the drift of a spiral wave in an excitable medium in the presence of an electric field. In contrast to earlier results, the drift speed presents a strong variation close to the…

Soft Condensed Matter · Physics 2007-05-23 Herve Henry

The turbulent diffusion tensor describing the evolution of the mean concentration of a passive scalar is investigated for non-helically forced turbulence in the presence of rotation or a magnetic field. With rotation, the Coriolis force…

Solar and Stellar Astrophysics · Physics 2009-05-09 Axel Brandenburg , Andreas Svedin , Geoffrey M. Vasil

For the understanding of planetary and stellar dynamos an overview of the major parameter dependences of convection driven dynamos in rotating spherical fluid shells is desirable. Although the computationally accessible parameter space is…

Fluid Dynamics · Physics 2009-04-29 F. H. Busse , R. D. Simitev

Hydrodynamic and magnetohydrodynamic convective attractors in three-dimensional rotating Rayleigh-B\'enard convection are studied numerically by varying the Taylor and Rayleigh numbers as control parameters. First, an analysis of…

Fluid Dynamics · Physics 2024-09-23 Dalton N. Oliveira , Roman Chertovskih , Erico L. Rempel , Francis F. Franco

We investigate analytically the amplification of a weak magnetic field in a homogeneous and isotropic turbulent flow lacking reflectional symmetry (helical turbulence). We propose that the spectral distributions of magnetic energy and…

Astrophysics · Physics 2007-05-23 Stanislav Boldyrev , Fausto Cattaneo , Robert Rosner

We have measured the statistical properties of magnetic reversal in nanomagnets driven by a spin-polarized current. Like reversal induced by a magnetic field, spin-transfer-driven reversal near room temperature exhibits the properties of…

Mesoscale and Nanoscale Physics · Physics 2009-11-07 E. B. Myers , F. J. Albert , J. C. Saneky , E. Bonet , R. A. Buhrman , D. C. Ralph

The magnetic field generated by an electron bound in a spherically symmetric potential is calculated for eigenstates of the orbital and total angular momentum. General expressions are presented for the current density in such states and the…

Quantum Physics · Physics 2009-10-31 K. Ayuel , P. F. de Chatel