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Magnetic fields correlated on several kiloparsec scales are seen in spiral galaxies. Their origin could be due to amplification of a small seed field by a turbulent galactic dynamo. We critically review the current status of the galactic…

Astrophysics · Physics 2007-05-23 Kandaswamy Subramanian

Origin of the magnetic field ubiquitous in the Universe is studied based on the Biermann mechanism, which is expected to work in the non-barotropic region. We perform a series of two-dimensional MHD simulations of the first generation…

Cosmology and Nongalactic Astrophysics · Physics 2010-11-17 Hidekazu Hanayama , Keitaro Takahashi , Kohji Tomisaka

Magnetic fields are observed beyond the peripheries of optically detected galactic discs, while numerical models of their origin and the typical magnitudes are still absent. Previously, studies of galactic dynamo have avoided considering…

Astrophysics of Galaxies · Physics 2014-09-05 E. Mikhailov , A. Kasparova , D. Moss , R. Beck , D. Sokoloff , A. Zasov

Primordial magnetic fields (PMFs) are possible candidates for explaining the observed magnetic fields in galaxy clusters. Two competing scenarios of primordial magnetogenesis have been discussed in the literature: inflationary and…

Cosmology and Nongalactic Astrophysics · Physics 2023-02-17 Salome Mtchedlidze , Paola Domínguez-Fernández , Xiaolong Du , Wolfram Schmidt , Axel Brandenburg , Jens Niemeyer , Tina Kahniashvili

We discuss the inflationary production of magnetic seeds for the galactic dynamo through the photon-graviphoton mixing typical of extended models of local supersymmetry. An analisys of the allowed region in parameter space shows that such a…

Astrophysics · Physics 2009-10-31 M. Gasperini

Three-dimensional electron phase space holes are shown to be positive charges on the plasma background which produce a radial electric field and force the trapped electron component into an azimuthal drift. In this way electron holes…

Space Physics · Physics 2012-04-20 R. A. Treumann , W. Baumjohann

Inflation is known to produce both gravitational waves and seed magnetic fields on scales well beyond the size of the horizon. The general relativistic interaction between these two sources at the end of inflation showed a significant…

Astrophysics · Physics 2009-11-13 Christos G. Tsagas

The exteriors of stellar and galactic dynamos are usually modeled as current-free potential fields. A more realistic description might instead be that of a force-free magnetic field. Here, we suggest that, in the absence of outflows,…

High Energy Astrophysical Phenomena · Physics 2026-05-06 Axel Brandenburg , Oindrila Ghosh , Franco Vazza , Andrii Neronov

Using superposition and numerical approximations of a published analytical expression for the magnetic field generated by a finite solenoid, we show that the magnetic field external to parallel identical solenoids can be nearly uniform and…

Classical Physics · Physics 2017-12-05 Melody Xuan Lim , Henry Greenside

A completely new mechanism to generate the observed amount of large-scale cosmological magnetic fields is introduced in the context of three-form inflation. The amplification of the fields occurs via fourth order dynamics of the vector…

Cosmology and Nongalactic Astrophysics · Physics 2012-04-17 Tomi S. Koivisto , Federico R. Urban

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

Cosmological and astrophysical observations indicate the presence of magnetic field over all scales. In order to explain these magnetic fields, it is assumed that there exists a seed magnetic field that gets amplified by dynamos. These seed…

Cosmology and Nongalactic Astrophysics · Physics 2021-09-06 Arun Kumar Pandey , Sampurn Anand

The possible existence of a primordial magnetic field in the universe has been previously investigated in many articles. Studies involving the influence of a magnetic field in the nucleosyntesis era, studies considering the effects in the…

Astrophysics · Physics 2009-10-30 J. C. N. de Araujo , R. Opher

We initiate numerical studies of differentially rotating magnetised (proto) neutron stars by studying - through construction from first principles - the coupling between an assumed differential rotation and an impressed magnetic field. For…

Astrophysics · Physics 2007-05-23 A. V. Thampan

Magnetic fields have been detected on stars across the H-R diagram and substellar objects either directly by their effect on the formation of spectral lines, or through the activity phenomena they power which can be observed across a large…

Solar and Stellar Astrophysics · Physics 2015-06-11 J. Morin

Inflation has the potential to seed the galactic magnetic fields observed today. However, there is an obstacle to the amplification of the quantum fluctuations of the electromagnetic field during inflation: namely the conformal invariance…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Amjad Ashoorioon , Robert B. Mann

Most of the baryonic matter in the Universe is permeated by magnetic fields which affect many, if not most, of astrophysical phenomena both, in compact sources and in diffuse gas. Recent years have been marked by a worldwide surge of…

Cosmology and Nongalactic Astrophysics · Physics 2010-03-23 Elisabete M. de Gouveia Dal Pino

Magnetic perturbations to the frequencies of low degree, high radial order, axisymmetric pulsations in stellar models permeated by large scale magnetic fields are presented. Magnetic fields with dipolar, quadrupolar and a superposition of…

Astrophysics · Physics 2008-11-26 M. S. Cunha

Magnetic fields observed across cosmic scales are difficult to explain within conventional physics. A primordial origin is, thus, often assumed. While a nonminimal coupling of the inflaton with the electromagnetic field could theoretically…

Cosmology and Nongalactic Astrophysics · Physics 2026-05-22 Debottam Nandi , Debajyoti Choudhury

Massive stars are crucial building blocks of galaxies and the universe, as production sites of heavy elements and as stirring agents and energy providers through stellar winds and supernovae. The field of magnetic massive stars has seen…

Solar and Stellar Astrophysics · Physics 2015-05-27 Rolf Walder , Doris Folini , Georges Meynet
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