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Related papers: Magnetized cosmological perturbations

200 papers

The generation of magnetohydrodynamic (MHD) waves and their instabilities are studied in galactic gaseous rotating plasmas with the effects of the magnetic field, the self gravity, the diffusion-convection of cosmic rays as well as the gas…

Plasma Physics · Physics 2022-11-07 Jyoti Turi , A. P. Misra

Gravitational instabilities in a magnetized Friedman - Robertson - Walker (FRW) Universe, in which the magnetic field was assumed to be too weak to destroy the isotropy of the model, are known and have been studied in the past. Accordingly,…

In most of the literature on evolution of cosmological magnetic fields, it is found that large-scale magnetic fields evolve as $B^{2}\propto a^{-4}$ (adiabatic magnetic decay) where $a$ is the cosmological scale factor and $B$ is the…

General Relativity and Quantum Cosmology · Physics 2020-04-23 Timothy Oreta , Bob Osano

We present a new mechanism for generation of large-scale magnetic field by thermal convection which does not involve the alpha-effect. We consider weakly nonlinear perturbations of space-periodic steady convective magnetic dynamos in a…

Fluid Dynamics · Physics 2015-12-01 Roman Chertovskih , Vladislav Zheligovsky

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

At second order in perturbation theory, the unstable r-mode of a rotating star includes growing differential rotation whose form and growth rate are determined by gravitational-radiation reaction. With no magnetic field, the angular…

High Energy Astrophysical Phenomena · Physics 2018-03-05 John L. Friedman , Lee Lindblom , Luciano Rezzolla , Andrey I. Chugunov

The existence of large-scale anisotropy can not be ruled out by the cosmic microwave background (CMB) radiation. Over the years, several models have been proposed in the context of anisotropic inflation to account for CMB's cold spot and…

Cosmology and Nongalactic Astrophysics · Physics 2023-11-15 Sourav Pal , Debaprasad Maity , Tuan Q. Do

Arguably the main challenge of galactic magnetism studies is to explain how the interstellar medium of galaxies reaches energetic equipartition despite the extremely weak cosmic primordial magnetic fields that are originally predicted to…

Astrophysics of Galaxies · Physics 2018-06-20 Sergio Martin-Alvarez , Julien Devriendt , Adrianne Slyz , Romain Teyssier

Strong magnetic fields in relativistic stars can be a cause of crust fracturing, resulting in the excitation of global torsional oscillations. Such oscillations could become observable in gravitational waves or in high-energy radiation,…

Astrophysics · Physics 2009-11-06 Neophytos Messios , Demetrios B. Papadopoulos , Nikolaos Stergioulas

We study the generation and evolution of density perturbations and peculiar velocities due to primordial magnetic fields. We assume that a random magnetic field was present before recombination and follow the field's effect on the baryon…

Astrophysics · Physics 2009-10-22 Eun-jin Kim , Angela Olinto , Robert Rosner

The evolution and viscous damping of cosmic magnetic fields in the early universe, is analysed. Using the fact that the fluid, electromagnetic, and shear viscous energy-momentum tensors are all conformally invariant, the evolution is…

Astrophysics · Physics 2011-09-29 Kandaswamy Subramanian , John D. Barrow

We study the role of viscosity and the effects of a magnetic field on a rotating, self-gravitating fluid, using Newtonian theory and adopting the ideal magnetohydrodynamic approximation. Our results confirm that viscosity can generate…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-03 F. Dosopoulou , F. Del Sordo , C. G. Tsagas , A. Brandenburg

In strongly compressible magnetohydrodynamic turbulence, obliqueness between the large-scale density gradient and magnetic field gives an electromotive force mediated by density variance (intensity of density fluctuation). This effect is…

Solar and Stellar Astrophysics · Physics 2022-05-31 Nobumitsu Yokoi , Steven M. Tobias

The growth and saturation of magnetic field in conducting turbulent media with large magnetic Prandtl numbers are investigated. This regime is very common in low-density hot astrophysical plasmas. During the early (kinematic) stage, weak…

Astrophysics · Physics 2009-11-07 A. A. Schekochihin , S. C. Cowley , G. W. Hammett , J. L. Maron , J. C. McWilliams

{\em Voyager 1} and {\em 2} data reveals that magnetic field fluctuations are compressive and exhibit a Gaussian distribution in the compressed heliosheath plasma, whereas they follow a lognormal distribution in a nearly incompressible…

Space Physics · Physics 2015-05-18 Dastgeer Shaikh

Magnetic fields interact with gravitational waves in various ways. We consider the coupling between the Weyl and the Maxwell fields in cosmology and study the effects of the former on the latter. The approach is fully analytical and the…

Cosmology and Nongalactic Astrophysics · Physics 2010-04-06 Christos G. Tsagas

Galactic magnetic fields are observed of order $\sim 10^{-6}G$, but their origin is not definitely known yet. In this paper we consider the primordial magnetic fields generated in the early universe and analyse their effects on the density…

Astrophysics · Physics 2016-08-30 Seoktae Koh , Chul H. Lee

Magnetic field amplification is an integral part of the process of particle acceleration at non-relativistic shocks. It is necessary to reach the maximum energies required by observations, especially in supernova remnants, thought to be…

High Energy Astrophysical Phenomena · Physics 2026-05-29 Antonio Capanema , Pasquale Blasi , Emanuele Sobacchi

Flow nonnormality induced linear transient phenomena in thin self-gravitating astrophysical discs are studied in the shearing sheet approximation. The considered system includes two modes of perturbations: vortex and (spiral density) wave.…

Astrophysics · Physics 2009-11-13 G. R. Mamatsashvili , G. D. Chagelishvili

In this work, we study the effect of a magnetic field on the growth of cosmological perturbations. We develop a mathematical consistent treatment in which a perfect fluid and a uniform magnetic field evolve together in a Bianchi I universe.…

General Relativity and Quantum Cosmology · Physics 2019-11-19 Federico Di Gioia , Giovanni Montani