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In dilute astrophysical plasmas, the collisional mean free path of a particle can exceed its Larmor radius. Under these conditions, the thermal conductivity and viscosity of the plasma can be dramatically altered. This alteration allows…

Astrophysics · Physics 2009-11-11 Tanim Islam , Steven Balbus

Primordial magnetic fields generated in the early universe are subject of considerable investigation, and observational limits on their strength are required to constrain the theory. Due to their impact on the reionization process, the…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-30 Dominik R. G. Schleicher , Francesco Miniati

We review here some magnetic phenomena in astrophysical particle accelerators associated with collisionless shocks in supernova remnants, radio galaxies and clusters of galaxies. A specific feature is that the accelerated particles can play…

High Energy Astrophysical Phenomena · Physics 2012-05-09 Andrei M. Bykov , Donald C. Ellison , Matthieu Renaud

Recently Ricca and Maggione [MHD (2008)] have presented a very simple and interesting model of stretch-twist-fold dynamo in diffusive media based on numerical simulations of Riemannian flux tubes. In this paper we present a yet simpler way…

Fluid Dynamics · Physics 2009-04-13 Garcia de Andrade

Chicone et al [CMP (1995)] have shown that, kinematic fast dynamos in diffusive media, could exist only on a closed, 2D Riemannian manifold of constant negative curvature. This report, shows that their result cannot be extended to…

Plasma Physics · Physics 2009-06-17 Garcia de Andrade

In weakly collisional extragalactic plasmas such as the intracluster medium, viscous stress and the rate of change of the magnetic-field strength are proportional to the local pressure anisotropy, so subject to constraints imposed by the…

Cosmology and Nongalactic Astrophysics · Physics 2015-08-26 Federico Mogavero , Alexander A. Schekochihin

Primordial magnetic fields (PMFs), which were generated in the early Universe before recombination, affect the motion of plasma and then the cosmic microwave background and the matter power spectrum. We consider constraints on PMFs with a…

Cosmology and Nongalactic Astrophysics · Physics 2013-12-03 Dai G. Yamazaki , Kiyotomo Ichiki , Keitaro Takahashi

In this paper, we revisit in detail the effects of primordial magnetic fields on big bang nucleosynthesis (BBN) including a discussion of the magnetic field geometry and the anomalous magnetic moment. The presence of magnetic fields affects…

Astrophysics · Physics 2009-12-30 Baolian Cheng , Angela V. Olinto , David N. Schramm , James W. Truran

The dynamo mechanism is a process of magnetic field self-excitation in a moving electrically conducting fluid. One of the most interesting applications of this mechanism related to the astrophysical systems is the case of a random motion of…

Solar and Stellar Astrophysics · Physics 2021-08-04 E. A. Illarionov , D. D. Sokoloff

Magnetic fields at the surface of a few early-type stars have been directly detected. These fields have magnitudes between a few hundred G up to a few kG. In one case, evidence of magnetic braking has been found. We investigate the effects…

Solar and Stellar Astrophysics · Physics 2015-05-20 Georges Meynet , Patrick Eggenberger , Andre Maeder

Simple exact solutions presented here describe the universes which spatial geometries are asymptotically homogeneous and isotropic near the initial singularity, but which evolution goes under the influence of primordial magnetic fields. In…

Cosmology and Nongalactic Astrophysics · Physics 2013-12-19 G. A. Alekseev

During stellar evolution, especially in the PMS, stellar structure and rotation evolve significantly causing major changes in the dynamics and global flows of the star. We wish to assess the consequences of these changes on stellar dynamo,…

Solar and Stellar Astrophysics · Physics 2017-09-15 Constance Emeriau-Viard , Allan Sacha Brun

We investigate hydromagnetic turbulence of primordial magnetic fields using magnetohydrodynamics (MHD) in an expanding universe. We present the basic, covariant MHD equations, find solutions for MHD waves in the early universe, and…

Astrophysics · Physics 2014-10-13 Axel Brandenburg , Kari Enqvist , Poul Olesen

Large scale strong magnetic fields in galaxies are generally thought to have been generated by a mean field dynamo. In order to have generated the fields observed, the dynamo would have had to have operated for a sufficiently long period of…

Astrophysics · Physics 2007-05-23 A. Kandus , R. Opher , S. R. M. Barros

A large-scale cosmic magnetic field affects not only the growth of density perturbations, but also rotational instabilities and anisotropic deformation in the density distribution. We give a fully relativistic treatment of all these…

Astrophysics · Physics 2008-11-26 Christos Tsagas , Roy Maartens

Recently Guenther et al the globally diagonalized ${\alpha}^{2}$ dynamo operator spectrum [J Phys A 2007) in mean field media, and its Krein space related perturbation theory [J Phys A 2006). Earlier, an example of fast dynamos in stretch…

Mathematical Physics · Physics 2010-03-15 L. C. Garcia de Andrade

In the standard cosmological model, magnetic fields and vorticity are generated during the radiation era via second-order density perturbations. In order to clarify the complicated physics of this second-order magnetogenesis, we use a…

Astrophysics · Physics 2008-11-26 Tsutomu Kobayashi , Roy Maartens , Tetsuya Shiromizu , Keitaro Takahashi

We study the generation of magnetic field in the primordial plasma of the standard model (SM) particles at temperature $T>80$~TeV much higher than the electroweak scale. It is assumed that there is an excess number of right-handed electrons…

Cosmology and Nongalactic Astrophysics · Physics 2016-09-07 Jitesh R. Bhatt , Arun Kumar Pandey

Faraday rotation induced B-modes can provide a distinctive signature of primordial magnetic fields because of their characteristic frequency dependence and because they are only weakly damped on small scales, allowing them to dominate…

Cosmology and Nongalactic Astrophysics · Physics 2011-09-29 Levon Pogosian , Amit P. S. Yadav , Yi-Fung Ng , Tanmay Vachaspati

While present standard model of cosmology yields no clear prediction for the initial magnetic field strength, efficient dynamo action may compensate for initially weak seed fields via rapid amplification. In particular, the small-scale…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-12 M. A. Latif , D. R. G. Schleicher , W. Schmidt , J. Niemeyer