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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…

广义相对论与量子宇宙学 · 物理学 2020-04-23 Timothy Oreta , Bob Osano

Motivated by the significant interaction of convection, rotation and magnetic field in many astrophysical objects, we investigate the interplay between large-scale flows driven by rotating convection and an imposed magnetic field. We…

太阳与恒星天体物理 · 物理学 2016-11-23 Laura K. Currie

We study the evolution of an inflation-generated magnetic field, due to its coupling to fluid motions, during cosmological phase transitions. We find that the magnetic field stays almost unchanged on large scales, while on small scales the…

宇宙学与河外天体物理 · 物理学 2013-05-30 Tina Kahniashvili , Axel Brandenburg , Leonardo Campanelli , Bharat Ratra , Alexander G. Tevzadze

It is shown that small-scale magnetic fields present before recombination induce baryonic density inhomogeneities of appreciable magnitude. The presence of such inhomogeneities changes the ionization history of the Universe, which in turn…

宇宙学与河外天体物理 · 物理学 2015-03-19 Karsten Jedamzik , Tom Abel

There is a reformulation of magnetohydrodynamics in which the fundamental dynamical quantities are the positions and velocities of the lines of magnetic flux in the plasma, which turn out to obey equations of motion very much like ideal…

天体物理学 · 物理学 2009-10-31 Mattias Christensson , Mark Hindmarsh

Magnetic fields are an elemental part of the interstellar medium in galaxies. However, their impact on gas dynamics and star formation in galaxies remains controversial. We use a suite of global magnetohydrodynamical simulations of isolated…

星系天体物理 · 物理学 2019-09-25 Bastian Körtgen , Robi Banerjee , Ralph E. Pudritz , Wolfram Schmidt

A primordial magnetic field may be generated during an inflationary period if conformal invariance is broken. We reexamine and generalize previous results about the magnetic field produced by couplings of the form $R^n…

天体物理学 · 物理学 2009-10-28 F. D. Mazzitelli , F. M. Spedalieri

A small fraction of the population of intermediate-mass and massive stars host strong and stable magnetic fields organised on large scales. These fields are believed to be remnants of star formation. It is however not clear how such fossil…

太阳与恒星天体物理 · 物理学 2021-03-10 E. Alecian , F. Villebrun , J. Grunhut , G. Hussain , C. Neiner , G. A. Wade

We describe the generation of the electric current flowing along the external magnetic field in the system of massive charged fermions, possessing anomalous magnetic moments and electroweakly interacting with background matter. This current…

高能物理 - 唯象学 · 物理学 2019-06-07 Maxim Dvornikov

An inhomogeneous cosmological magnetic field creates vortical perturbations that survive Silk damping on much smaller scales than compressional modes. This ensures that there is no sharp cut-off in anisotropy on arc-minute scales. As we had…

天体物理学 · 物理学 2009-11-07 Kandaswamy Subramanian , John D. Barrow

It has been recently proposed that the presence of a temporal electromagnetic field on cosmological scales could explain the phase of accelerated expansion that the universe is currently undergoing. The field contributes as a cosmological…

综合物理 · 物理学 2009-11-13 Jose Beltran Jimenez , Tomi S. Koivisto , Antonio L. Maroto , David F. Mota

We study the evolution of primordial magnetic fields until the recombination epoch, which is constrained by the conservation of magnetic helicity density if they are maximally helical and by the Hosking integral if they are non-helical. We…

宇宙学与河外天体物理 · 物理学 2025-08-07 Fumio Uchida , Motoko Fujiwara , Kohei Kamada , Jun'ichi Yokoyama

It is widely believed that primordial magnetic fields are dramatically diluted by the expansion of the universe. As a result, cosmological magnetic fields with residual strengths of astrophysical relevance are generally sought by going…

宇宙学与河外天体物理 · 物理学 2015-05-27 John D. Barrow , Christos G. Tsagas

Cosmic magnetic fields may be generated during early cosmic phase transition, such as the QCD- or electroweak- transitions. The magnitude of the remainder of such fields at the present epoch crucially depends on the exponent $n$ of their…

宇宙学与河外天体物理 · 物理学 2011-06-02 Karsten Jedamzik , Guenter Sigl

Recent observations by Chandra and XMM-Newton indicate there are complex structures at the cores of galaxy clusters, such as cavities and filaments. One plausible model for the formation of such structures is the interaction of radio jets…

宇宙学与河外天体物理 · 物理学 2014-11-20 Ruobing Dong , James M. Stone

Observations show that galaxies and their interstellar media are pervaded by strong magnetic fields with energies in the diffuse component being at least comparable to the thermal and even as large or larger than the turbulent energy. Such…

星系天体物理 · 物理学 2018-06-06 Bastian Körtgen , Robi Banerjee , Ralph E. Pudritz , Wolfram Schmidt

Blazar observations point toward the possible presence of magnetic fields over intergalactic scales of the order of up to $\sim1\,$Mpc, with strengths of at least $\sim10^{-16}\,$G. Understanding the origin of these large-scale magnetic…

宇宙学与河外天体物理 · 物理学 2020-03-17 Tina Kahniashvili , Axel Brandenburg , Arthur Kosowsky , Sayan Mandal , Alberto Roper Pol

Using a generally covariant Electro-Vortic (magnetofluid) formalism for relativistic plasmas, the dynamical evolution of a generalized vorticity (a combination of the magnetic and kinematic parts) is studied in a cosmological context. We…

等离子体物理 · 物理学 2019-05-22 Felipe A. Asenjo , Swadesh M. Mahajan

The origin and structure of the magnetic fields in the interstellar medium of spiral galaxies is investigated with 3D, non-ideal, compressible MHD simulations, including stratification in the galactic gravity field, differential rotation…

星系天体物理 · 物理学 2013-04-01 F. A. Gent , A. Shukurov , A. Fletcher , G. R. Sarson , M. J. Mantere

The nature and origin of turbulence and magnetic fields in the intergalactic space are important problems that are yet to be understood. We propose a scenario in which turbulent flow motions are induced via the cascade of the vorticity…

天体物理学 · 物理学 2009-11-13 Dongsu Ryu , Hyesung Kang , Jungyeon Cho , Santabrata Das