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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

An analytical model predicting the growth rates, the absolute growth times and the saturation values of the magnetic field strength within galactic haloes is presented. The analytical results are compared to cosmological MHD simulations of…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 Alexander M. Beck , Harald Lesch , Klaus Dolag , Hanna Kotarba , Annette Geng , Federico A. Stasyszyn

Observations of magnetism in very low mass stars recently made important progress, revealing characteristics that are now to be understood in the framework of dynamo theory. In parallel, there is growing evidence that dynamo processes in…

Solar and Stellar Astrophysics · Physics 2015-05-28 J. Morin , E. Dormy , M. Schrinner , J. -F. Donati

We construct a magnetic helicity conserving dynamo theory which incorporates a calculated magnetic helicity current. In this model the fluid helicity plays a small role in large scale magnetic field generation. Instead, the dynamo process…

Astrophysics · Physics 2009-10-31 Ethan T. Vishniac , Jungyeon Cho

It is demonstrated that strong magnetic fields are produced from a zero initial magnetic field during the pregalactic era, when galaxies are first forming. Their development proceeds in three phases. In the first phase, weak magnetic fields…

Astrophysics · Physics 2011-02-11 Russell M. Kulsrud , Renyue Cen , Jeremiah P. Ostriker , Dongsu Ryu

The generation process of magnetic field around a proto-first-star is studied. Utilizing the recent numerical result of proto-first-star formation based upon the radiation hydrodynamics simulations, we assess the magnetic field strength…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-18 Yuki Shiromoto , Hajime Susa , Takashi Hosokawa

We study the evolution of magnetic fields generated by charge segregation ahead of ionization fronts during the Epoch of Reionization, and their effects on galaxy formation. We compare this magnetic seeding process with the Biermann…

Astrophysics of Galaxies · Physics 2021-01-27 Enrico Garaldi , Rüdiger Pakmor , Volker Springel

Stellar dynamos are driven by complex couplings between rotation and turbulent convection, which drive global-scale flows and build and rebuild stellar magnetic fields. When stars like our sun are young, they rotate much more rapidly than…

The amplification of magnetic fields is crucial for understanding the observed magnetization of stars and galaxies. Turbulent dynamo is the primary mechanism responsible for that but the understanding of its action in a collapsing…

Astrophysics of Galaxies · Physics 2026-04-22 Muhammed Irshad P , Pallavi Bhat , Kandaswamy Subramanian , Anvar Shukurov

In this work, we show that ultralight dark photons, which couple to the Standard Model photon through kinetic mixing, can potentially source galactic scale magnetic fields. Although these magnetic fields would be too weak to detect at…

High Energy Physics - Phenomenology · Physics 2026-02-11 Joshua Berger , Amit Bhoonah , Joseph Bramante , J. Leo Kim , Ningqiang Song , Lawrence M. Widrow

We investigate generation processes of magnetic fields around first stars. Since the first stars are expected to form anisotropic ionization fronts in the surrounding clumpy media, magnetic fields are generated by effects of radiation force…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-30 Kentaro Doi , Hajime Susa

Spectropolarimetric observations show that many low-mass stars possess large-scale poloidal magnetic fields with considerable dipole component, which in some cases exhibit temporal dynamics - cycles or reversals. Although it is widely…

Solar and Stellar Astrophysics · Physics 2025-07-02 Anna Guseva , Ludovic Petitdemange , Charly Pinçon

We study the evolution of QCD phase transition-generated magnetic fields in freely decaying MHD turbulence of the expanding Universe. We consider a magnetic field generation model that starts from basic non-perturbative QCD theory and…

Cosmology and Nongalactic Astrophysics · Physics 2012-10-18 Alexander G. Tevzadze , Leonard Kisslinger , Axel Brandenburg , Tina Kahniashvili

The origin and growth of magnetic fields in galaxies is still something of an enigma. It is generally assumed that seed fields are amplified over time through the dynamo effect, but there are few constraints on the timescale. It has…

The surface magnetic field strength of white dwarfs is observed to vary from very little to around 10^9 G. Here we examine the proposal that the strongest fields are generated by dynamo action during the common envelope phase of strongly…

Solar and Stellar Astrophysics · Physics 2009-12-12 Adrian T. Potter , Christopher A. Tout

The existence of magnetic fields in the universe is unmistakable. They are observed at all scales from stars to galaxy clusters. However, the origin of these fields remains enigmatic. It is believed that magnetic field seeds may have…

General Relativity and Quantum Cosmology · Physics 2022-08-17 Orfeu Bertolami , Maria Margarida Lima , Filipe C. Mena

Magnetic fields are observed on nearly all scales in the universe, from stars and galaxies upto galaxy clusters and even beyond. The origin of cosmic magnetic fields is still an open question, however a large class of models puts its origin…

Cosmology and Nongalactic Astrophysics · Physics 2013-12-19 Kerstin E. Kunze

Using the generally covariant magnetofluid formalism for a hot plasma, a new curvature (of space time) driven mechanism for generating seed vorticity/magnetic field is presented. The "battery" owes its origin to the interaction between…

High Energy Astrophysical Phenomena · Physics 2012-10-09 Swadesh M. Mahajan , Felipe A. Asenjo

Magnetic fields play a vital role in numerous astrophysical processes such as star formation and the interstellar medium. In particular, their role in the formation and evolution of galaxies is not well understood. This paper presents…

Astrophysics of Galaxies · Physics 2021-12-10 Huai-Hsuan Chiu , Ke-Jung Chen

We numerically investigate the generation of a magnetic field in a protostellar disc via an $\alpha \Omega$-dynamo and the resulting magnetohydrodynamic (MHD) driven outflows. We find that for small values of the dimensionless dynamo…

High Energy Astrophysical Phenomena · Physics 2018-03-05 Sergei Dyda , Richard V. E. Lovelace , Galina V. Ustyugova , Alexander V. Koldoba , Ira Wasserman