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We present an analytic model of a magnetized galactic halo surrounding a Mestel gravitating disc. The magnetic field is taken to be in energy equipartition with the pressure dominant rotating halo gas ({\it not} with the cosmic rays), and…

Astrophysics of Galaxies · Physics 2016-03-23 Richard N. Henriksen , Judith A. Irwin

Radio continuum and polarization observations of several nearby galaxies allowed to determine their vertical scaleheights, magnetic field strengths and large-scale magnetic field patterns. They all show a similar large-scale magnetic field…

Astrophysics of Galaxies · Physics 2012-07-13 Marita Krause

In this review, I will first introduce possible methods to probe the large-scale magnetic fields in our Galaxy and discuss their limitations. The magnetic fields in the Galactic halo, mainly revealed by the sky distribution of rotation…

Astrophysics · Physics 2007-05-23 J. L. Han

The origin and maintenance of large scale magnetic fields in the Universe is discussed. A popular idea is that cosmic batteries generate seed magnetic fields which were amplified by magnetic induction due to turbulent motions, at times…

Cosmology and Nongalactic Astrophysics · Physics 2018-09-12 Kandaswamy Subramanian

The large-scale structure of the Universe has been observed to be characterized by long filaments, forming polyhedra, with a remarkable 100-200 Mpc periodicity, suggesting a regular network. The introduction of magnetic fields into the…

Astrophysics · Physics 2007-05-23 E. Battaner , E. Florido

Combined action of helical motions of plasma (the $\alpha$ effect) and non-uniform (differential) rotation is a key dynamo mechanism of solar and galactic large-scale magnetic fields. Dynamics of magnetic helicity of small-scale fields is a…

Solar and Stellar Astrophysics · Physics 2022-09-20 N. Kleeorin , I. Rogachevskii

The existence of magnetic fields associated with the intracluster medium in clusters of galaxies is now well established through different methods of analysis. Magnetic fields are investigated in the radio band from studies of the rotation…

Astrophysics · Physics 2009-11-10 Federica Govoni , Luigina Feretti

Magnetic fields play an important role in producing and modifying the photospheric chemical peculiarities of intermediate-mass main sequence stars. This article discusses the basic theory and methods of measurement used to detect and…

Astrophysics · Physics 2007-05-23 G. A. Wade

In this paper we investigate the dynamics of magnetic helicity in magnetohydrodynamic (MHD) turbulent flows focusing at scales larger than the forcing scale. Our results show a nonlocal inverse cascade of magnetic helicity, which occurs…

Fluid Dynamics · Physics 2017-05-23 Moritz Linkmann , Vassilios Dallas

The magnetic fields we observe in galaxies today may have their origins in the very early universe. While a number of mechanisms have been proposed which lead to an appreciable field amplitude at early times, the subsequent evolution of the…

Astrophysics · Physics 2007-05-23 Sean M. Carroll , George B. Field

Magnetic field relaxation is determined by both the field's geometry and its topology. For relaxation processes, however, it turns out that its topology is a much more stringent constraint. As quantifier for the topology we use magnetic…

Solar and Stellar Astrophysics · Physics 2013-11-18 Simon Candelaresi , Axel Brandenburg

(abridged) A detailed examination of the evolution of stochastic magnetic fields between high cosmic temperatures and the present epoch is presented. A simple analytical model matching the results of the 3D MHD simulations allows for the…

Astrophysics · Physics 2009-11-10 Robi Banerjee , Karsten Jedamzik

Magnetic fields play an important role in astrophysical accretion discs, and in the interstellar and intergalactic medium. They drive jets, suppress fragmentation in star-forming clouds and can have a significant impact on the accretion…

Plasma Physics · Physics 2016-12-30 Christoph Federrath

Mean field dynamos may explain the origin of large scale magnetic fields of galaxies, but controversy arises over the extent of dynamo quenching by the growing field. Here we explain how apparently conflicting results may be mutually…

Astrophysics · Physics 2007-05-23 Eric G. Blackman , George B. Field

We discuss inverse problem of detection turbulence magnetic field helical properties using radio survey observations statistics. In this paper, we present principal solution which connects magnetic helicity and correlation between Faraday…

Instrumentation and Methods for Astrophysics · Physics 2010-01-19 A. Volegova , R. Stepanov

Magnetic fields in galaxy clusters have been measured using a variety of techniques, including: studies of synchrotron relic and halo radio sources within clusters, studies of inverse Compton X-ray emission from clusters, surveys of Faraday…

Astrophysics · Physics 2009-11-07 C. L. Carilli , G. B. Taylor

Primordial magnetic fields may account for all or part of the fields observed in galaxies. We consider the evolution of the magnetic fields created by pseudoscalar effects in the early universe. Such processes can create force-free fields…

Astrophysics · Physics 2009-10-31 George B. Field , Sean M. Carroll

Recent rotation measure observations of a dozen or so galaxy clusters have revealed a surprisingly large amount of magnetic fields, whose estimated energy and flux are, on average, $\sim 10^{58}$ ergs and $\sim 10^{41}$ G cm$^2$,…

Astrophysics · Physics 2007-05-23 Stirling A. Colgate , Hui Li

A convenient representation of the structure of the large-scale galactic magnetic field is required for the interpretation of polarization data in the sub-mm and radio ranges, in both the Milky Way and external galaxies. We develop a simple…

Astrophysics of Galaxies · Physics 2019-03-14 Anvar Shukurov , Luiz Felippe S. Rodrigues , Paul J. Bushby , James Hollins , Jorg P. Rachen

Magnetic field generation on scales large compared with the scale of the turbulent eddies is known to be possible via the so-called $\alpha$ effect when the turbulence is helical and if the domain is large enough for the $\alpha$ effect to…

Solar and Stellar Astrophysics · Physics 2013-11-18 Simon Candelaresi , Axel Brandenburg