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The origin of galactic and extra-galactic magnetic fields is an unsolved problem in modern cosmology. A possible scenario comes from the idea of these fields emerged from a small field, a seed, which was produced in the early universe…

Cosmology and Nongalactic Astrophysics · Physics 2013-06-14 Hector J. Hortua , Leonardo Castaneda , Juan M. Tejeiro

Previously Liao and Shuryak [\textbf{Phys. Rev C (2008)}] have investigated electrical flux tubes in monopole plasmas, where magnetic fields are non-solenoidal in quark-QCD plasmas. In this paper slow dynamos in diffusive plasma…

Cosmology and Nongalactic Astrophysics · Physics 2009-01-23 Garcia de Andrade

We explore the decay of turbulence and magnetic fields generated by fluctuation dynamo action in the context of galaxy clusters where such a decaying phase can occur in the aftermath of a major merger event. Using idealized numerical…

Cosmology and Nongalactic Astrophysics · Physics 2019-08-28 Sharanya Sur

We argue that global magnetic field reversals similar to those observed in the Milky Way occur quite frequently in mean-field galactic dynamo models that have relatively strong, random, seed magnetic fields that are localized in discrete…

Astrophysics of Galaxies · Physics 2015-06-11 David Moss , Dmitri Sokoloff

(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

In this work we present a generalized Brans-Dicke lagrangian including a non-minimally coupled Gauss-Bonnet term without imposing the vanishing torsion condition. In the resulting field equations, the torsion is closely related to the…

General Relativity and Quantum Cosmology · Physics 2018-04-19 Antonella Cid , Fernando Izaurieta , Genly Leon , Perla Medina , Daniela Narbona

Large-scale magnetic fields are observed today to be coherent on galactic scales. While there exists an explanation for their amplification and their specific configuration in spiral galaxies -- the dynamo mechanism -- a satisfying…

High Energy Physics - Theory · Physics 2009-12-04 Rhiannon Gwyn , Stephon Alexander , Robert H. Brandenberger , Keshav Dasgupta

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

This letter concentrates on the non-equilibrium evolution of magnetic field structures at the onset of recombination, when the charged particle current densities decay as neutrals are formed. We consider the effect that a decaying magnetic…

Astrophysics · Physics 2009-11-13 Declan A. Diver , Luis F. A. Teodoro

The braiding of the solar coronal magnetic field via photospheric motions - with subsequent relaxation and magnetic reconnection -- is one of the most widely debated ideas of solar physics. We readdress the theory in the light of…

Astrophysics · Physics 2011-02-11 A. L. Wilmot-Smith , G. Hornig , D. I. Pontin

We study interacting classical magnetic and pseudoscalar fields in frames of the axion electrodynamics. A large scale pseudoscalar field can be the coherent superposition of axions or axion like particles. We consider the evolution of these…

High Energy Physics - Phenomenology · Physics 2024-01-09 Maxim Dvornikov

Magnetic fields are ubiquitous in the Universe. Extragalactic disks, halos and clusters have consistently been shown, via diffuse radio-synchrotron emission and Faraday rotation measurements, to exhibit magnetic field strengths ranging from…

The observed galactic magnetic fields may have a primordial origin. I briefly review the observations, their interpretation in terms of the dynamo theory, and the current limits on cosmological magnetic fields. Several possible mechanisms…

Astrophysics · Physics 2007-05-23 Kari Enqvist

This paper concerns the generation and evolution of the cosmological (large-scale $\sim Mpc$) magnetic fields in an inflationary universe. The universe during inflation is represented by de Sitter space-time. We started with the Maxwell…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Zuxiang Dai

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

We consider the evolution of primordial magnetic fields generated during cosmological, electroweak or QCD, phase transitions. We assume that the magnetic field generation can be described as an injection of magnetic energy to cosmological…

Cosmology and Nongalactic Astrophysics · Physics 2013-04-24 Tina Kahniashvili , Alexander G. Tevzadze , Axel Brandenburg , Andrii Neronov

We present a scenario for efficient magnetization of very young galaxies about 0.5 Gigayears after the Big-Bang by a cosmic ray-driven dynamo. These objects experience a phase of strong star formation during this first $10^9$ years. We…

Astrophysics · Physics 2009-11-07 H. Lesch , M. Hanasz

Magnetic field embedded in a perfectly conducting fluid preserves its topology for all time. Although ionized astrophysical objects, like stars and galactic disks, are almost perfectly conducting, they show indications of changes in…

Astrophysics of Galaxies · Physics 2010-03-16 A. Lazarian , G. Kowal , E. Vishniac , K. Kulpa-Dubel , K. Otmianowska-Mazur

Magnetic fields are widely recognised as critical at many scales to galactic dynamics and structure, including multiphase pressure balance, dust processing, and star formation. Using imposed magnetic fields cannot reliably model the…

Astrophysics of Galaxies · Physics 2024-01-17 Frederick A. Gent , Mordecai-Mark Mac Low , Maarit J. Korpi-Lagg

Astrophysical objects with negligible resistivity are often threaded by large scale magnetic fields. The generation of these fields is somewhat mysterious, since a magnetic field in a perfectly conducting fluid cannot change the flux…

Astrophysics · Physics 2007-05-23 E. T. Vishniac , A. Lazarian , J. Cho