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Related papers: Primordial magnetic fields constrained by CMB anis…

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Faraday rotation and synchrotron emission from extragalactic radio sources give evidence for the presence of magnetic fields extending over ~Mpc scales. However, the origin of these fields remains elusive. With new high-resolution grid…

Cosmology and Nongalactic Astrophysics · Physics 2017-12-27 F. Vazza , G. Brunetti , M. Brüggen , A. Bonafede

Efficient acceleration of cosmic rays (via the mechanism of diffusive shock acceleration) requires turbulent, amplified magnetic fields in the shock's upstream region. We present results of multidimensional particle-in-cell simulations…

High Energy Astrophysical Phenomena · Physics 2014-11-20 Thomas Stroman , Martin Pohl , Jacek Niemiec

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

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…

We construct a time-dependent, incompressible, and uniformly-in-time Lipschitz continuous velocity field on $\mathbb{T}^3$ that produces exponential growth of the magnetic energy along a subsequence of times, for every positive value of the…

Analysis of PDEs · Mathematics 2025-12-02 Massimo Sorella , David Villringer

We consider the possibility that cosmic magnetic field, instead of being uniformly distributed, is strongly correlated with the large scale structure of the universe. Then, the observed rotational measure of extra-galactic radio sources…

Astrophysics · Physics 2011-07-19 Dongsu Ryu , Hyesung Kang , Peter L. Biermann

The origin of the observed large scale magnetic fields in the Universe is a mystery. The seed of these magnetic fields has been attributed to physical process in the early universe. In this work we provide a mechanism for the generation of…

High Energy Physics - Phenomenology · Physics 2016-09-12 Abhishek Atreya , Soma Sanyal

The Universe at present is highly magnetized, with fields of the order of a few 10^-5 G and coherence lengths larger than 10 kpc in typical galaxies like the Milky Way. We propose that the magnetic field was amplified to this values already…

Astrophysics of Galaxies · Physics 2015-06-17 Jennifer Schober , Dominik R. G. Schleicher , Ralf S. Klessen

We perform three-dimensional numerical simulations of stellar winds of early-M dwarf stars. Our simulations incorporate observationally reconstructed large-scale surface magnetic maps, suggesting that the complexity of the magnetic field…

Solar and Stellar Astrophysics · Physics 2015-06-18 A. A. Vidotto , M. Jardine , J. Morin , J. F. Donati , M. Opher , T. I. Gombosi

Recently Shukurov et al [Phys Rev \textbf{E} (2008)] presented a numerical solution of a Moebius strip dynamo flow, to investigate its use in modelling dynamo flows in Perm torus of liquid sodium dynamo experiments. Here, by analogy one…

Plasma Physics · Physics 2009-11-25 L C Garcia de Andrade

The problem of the dynamo effect for a Kraichnan incompressible helicity-free velocity field is considered. Exploiting a quantum formalism first introduced by Kazantsev (A.P. Kazantsev, Sov. Phys. JETP 26, 1031-1034 (1968)), we show that a…

Fluid Dynamics · Physics 2007-05-23 D. Vincenzi

Magnetic fields in nearby, star-forming galaxies reveal both large-scale patterns and small-scale structures. A large-scale field reversal may exist in the Milky Way but no such reversals have been observed so far in external galaxies. The…

Astrophysics of Galaxies · Physics 2015-05-30 David Moss , Rodion Stepanov , Tigran Arshakian , Rainer Beck , Marita Krause , Dmitri Sokoloff

Main-sequence massive stars possess convective cores that likely harbor strong dynamo action. To assess the role of core convection in building magnetic fields within these stars, we employ the 3-D anelastic spherical harmonic (ASH) code to…

Solar and Stellar Astrophysics · Physics 2015-05-20 Kyle C. Augustson , Allan S. Brun , Juri Toomre

It is shown that the standard cosmological model predicts {\it ab initio} generation of large-scale but very small-amplitude cosmic magnetic fields at the epoch of recombination of the primeval plasma. Matter velocities dominated by…

Astrophysics · Physics 2007-05-23 Craig J. Hogan

Magnetic fields appear to be present in essentially all astrophysical environments, including galaxies, clusters of galaxies and voids. There are both observational and theoretical motives for considering the possibility of their origin…

Cosmology and Nongalactic Astrophysics · Physics 2023-07-12 Karsten Jedamzik , Levon Pogosian

Cosmological magnetic fields in open Friedmann universes can experience superadiabatic amplification within the realm of conventional electromagnetism. This is possible mathematically, despite the conformal invariance of Maxwell's…

General Relativity and Quantum Cosmology · Physics 2015-06-05 J. D. Barrow , C. G. Tsagas , K. Yamamoto

When a star gets tidally disrupted by a supermassive black hole, its magnetic field is expected to pervade its debris. In this paper, we study this process via smoothed particle magnetohydrodynamical simulations of the disruption and early…

High Energy Astrophysical Phenomena · Physics 2017-06-28 Clément Bonnerot , Daniel J. Price , Giuseppe Lodato , Elena M. Rossi

It has been recently claimed that primordial magnetic fields could relieve the cosmological Hubble tension. We consider the impact of such fields on the formation of the first cosmological objects, mini-halos forming stars, for present-day…

Cosmology and Nongalactic Astrophysics · Physics 2021-03-17 Daegene Koh , Tom Abel , Karsten Jedamzik

We compare the current effects of rotation in stellar evolution to those of the magnetic field created by the Tayler instability. In stellar regions, where magnetic field can be generated by the dynamo due to differential rotation (Spruit…

Astrophysics · Physics 2009-11-10 Andre Maeder , Georges Meynet

In a recent paper (Phys. Rev. Lett. 94 (2005), 184506; physics/0411050) it was shown that a simple mean-field dynamo model with a spherically symmetric helical turbulence parameter alpha can exhibit a number of features which are typical…

Geophysics · Physics 2007-05-23 Frank Stefani , Gunter Gerbeth , Uwe Guenther , Mingtian Xu
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