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We give a pedagogical introduction to two aspects of magnetic fields in the early universe. We first focus on how to formulate electrodynamics in curved space time, defining appropriate magnetic and electric fields and writing Maxwell…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-20 Kandaswamy Subramanian

The nature of magnetic fields in the voids of the large-scale structure of the Universe has been a multifaceted open puzzle for decades. On one hand, their origin is not clear with most of the magnetogenesis models using physics beyond the…

Cosmology and Nongalactic Astrophysics · Physics 2025-10-09 Deepen Garg , Ruth Durrer , Jennifer Schober

Today, the generation of magnetic fields in solar-type stars and its relation to activity and rotation can coherently be explained, although it is certainly not understood in its entirety. Rotation facilitates the generation of magnetic…

Astrophysics · Physics 2009-11-13 A. Reiners , A. Scholz , J. Eislöffel , G. Hallinan , E. Berger , M. Browning , J. Irwin , M. Küker , S. Matt

The origin of magnetic fields in the Universe is an open problem in astrophysics and fundamental physics. Our present-day knowledge is limited to regions of strong magnetic fields and to star-forming disks of galaxies. Low-energy electrons…

Cosmology and Nongalactic Astrophysics · Physics 2009-09-02 Rainer Beck

The origin of extragalactic magnetic fields is still poorly understood. Based on a dedicated suite of cosmological magneto-hydrodynamical simulations with the ENZO code we have performed a survey of different models that may have caused…

Cosmology and Nongalactic Astrophysics · Physics 2017-11-22 F. Vazza , M. Brüggen , C. Gheller , S. Hackstein , D. Wittor , P. M. Hinz

Magnetic fields play a pivotal role in the physics of interstellar medium in galaxies, but there are few observational constraints on how they evolve across cosmic time. Spatially resolved synchrotron polarization maps at radio wavelengths…

Astrophysics of Galaxies · Physics 2017-08-30 S. A. Mao , C. Carilli , B. M. Gaensler , O. Wucknitz , C. Keeton , A. Basu , R. Beck , P. P. Kronberg , E. Zweibel

We investigate the generation of large scale magnetic fields in the universe from quantum fluctuations produced in the inflationary stage. By coupling these quantum fluctuations to the dilaton field and Ricci scalar, we show that the…

Astrophysics · Physics 2008-11-26 A. Akhtari Zavareh , A. Hojjati , B. Mirza

Magnetic fields play an important role in the dynamics of present-day molecular clouds. Recent work has shown that magnetic fields are equally important for primordial clouds, which form the first stars in the Universe. While the primordial…

Astrophysics of Galaxies · Physics 2021-02-24 Piyush Sharda , Christoph Federrath , Mark R. Krumholz , Dominik R. G. Schleicher

The existence of a weak galactic magnetic field has been repeatedly confirmed by observational data. The origin of this field has not as yet been explained in a fully satisfactory way and represents one of the main challenges of the…

Astrophysics · Physics 2009-11-06 Alexander Schekochihin , Stanislav Boldyrev , Russell Kulsrud

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…

Cosmology and Nongalactic Astrophysics · Physics 2011-06-02 Karsten Jedamzik , Guenter Sigl

The generation of magnetic field in an electrically conducting fluid generally involves the complicated nonlinear interaction of flow turbulence, rotation and field. This dynamo process is of great importance in geophysics, planetary…

Fluid Dynamics · Physics 2021-10-04 Steven Tobias

Convectively driven dynamos with rotation generating magnetic fields on scales large compared with the scale of the turbulent eddies are being reviewed. It is argued that such fields can be understood as the result of an alpha effect.…

Solar and Stellar Astrophysics · Physics 2011-08-19 A. Brandenburg , P. J. Käpylä , M. J. Korpi

The hot plasma above the electroweak scale contains (hyper) charged scalar particles which are coupled to Abelian gauge fields. Scalars may interact with gravity in a non-conformally invariant way and thus their fluctuations can be…

High Energy Physics - Phenomenology · Physics 2009-10-31 M. Giovannini , M. Shaposhnikov

A great deal of study has been carried out over the last twenty years on the origin of the magnetic activity in the Galactic center. One of the most popular hypotheses assumes milli-Gauss magnetic field with poloidal geometry, pervading the…

Astrophysics · Physics 2007-05-23 Stanislav Boldyrev , Farhad Yusef-Zadeh

Magnetic fields play a very important role in the evolution of galaxies through their direct impact on star formation and stellar feedback-induced turbulence. However, their co-evolution with these processes has still not been thoroughly…

Astrophysics of Galaxies · Physics 2018-11-14 Evangelia Ntormousi

(abridged) We suggest here that the large scale fields $\sim \mu$G, observed in galaxies at both high and low redshifts by Faraday Rotation Measurements (FRMs), have their origin in the electromagnetic fluctuations that naturally occurred…

Astrophysics · Physics 2008-11-26 Rafael S. de Souza , Reuven Opher

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

The existence of microgauss magnetic fields in galaxy clusters have been established through observations of synchrotron radiation and Faraday rotation. They are conjectured to be generated via small-scale dynamo by turbulent flow motions…

High Energy Astrophysical Phenomena · Physics 2020-01-15 Soonyoung Roh , Dongsu Ryu , Hyesung Kang , Seungwoo Ha , Hanbyul Jang

Arguably the main challenge of galactic magnetism studies is to explain how the interstellar medium of galaxies reaches energetic equipartition despite the extremely weak cosmic primordial magnetic fields that are originally predicted to…

Astrophysics of Galaxies · Physics 2018-06-20 Sergio Martin-Alvarez , Julien Devriendt , Adrianne Slyz , Romain Teyssier

The mechanisms that generate "seed" magnetic fields in our Universe and that amplify them throughout cosmic time remain poorly understood. By means of fully-kinetic particle-in-cell simulations of turbulent, initially unmagnetized plasmas,…

Cosmology and Nongalactic Astrophysics · Physics 2023-08-09 L. Sironi , L. Comisso , R. Golant