Related papers: Magnetic Fields in the Early Universe
In early-type stars a fossil magnetic field may be generated during the star formation process or be the result of a stellar merger event. Surface magnetic fields are thought to be erased by (sub)surface convection layers, which typically…
The origin of cosmic magnetic (B) fields remains an open question. It is generally believed that very weak primordial B fields are amplified by dynamo processes, but it appears unlikely that the amplification proceeds fast enough to account…
We demonstrate that a quasi-uniform cosmological seed field is a much less suitable seed for a galactic dynamo than has often been believed. The age of the Universe is insufficient for a conventional galactic dynamo to generate a…
We argue that the first stars may have spanned the conventional mass range rather than be identified with the Very Massive Objects (100-1000 solar masses) favoured by numerical simulations. Specifically, we find that magnetic field…
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…
Microgauss magnetic fields are observed in all galaxies at low and high redshifts. The origin of these intense magnetic fields is a challenging question in astrophysics. We show here that the natural plasma fluctuations in the primordial…
A framework is introduced for coupling the evolution of galactic magnetic fields sustained by the mean-field dynamo with the formation and evolution of galaxies in cold dark matter cosmology. Estimates of the steady-state strength of the…
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…
The origin of large scale cosmological magnetic fields remains a mystery, despite the continuous efforts devoted to that problem. We present a new model of magnetic field generation, based on local charge separation provided by an…
We give an improved estimate of primordial magnetic fields generated during cosmological first order phase transitions. We examine the charge distribution at the nucleated bubble wall and its dynamics. We consider instabilities on the…
In this review, I will summarise what we know about magnetic fields in stars and what the origin of these magnetic fields may be. I will address the issue of whether the magnetic flux is conserved from pre-main sequence to the compact star…
Large scale primordial magnetic fields (PMFs) threading the intergalactic medium are observed ubiquitously in the Universe playing a key role in the cosmic evolution. Their origin is still debated constituting a very active field of…
We present results of a detailed and fully non-linear numerical and analytical investigation of magnetic field evolution from the very earliest cosmic epochs to the present. We find that, under reasonable assumptions concerning the…
We propose a primordial-origin model for the composite configurations of global magnetic fields in spiral galaxies. We show that uniform tilted magnetic field wound up into a rotating disk galaxy can evolve into composite magnetic…
Large-scale coherent magnetic fields are observed in galaxies and clusters, but their ultimate origin remains a mystery. We reconsider the prospects for primordial magnetogenesis by a cosmic string network. We show that the magnetic flux…
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…
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…
(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…
The first galaxies form due to gravitational collapse of primordial halos. During this collapse, weak magnetic seed fields get amplified exponentially by the small-scale dynamo - a process converting kinetic energy from turbulence into…
Observations of dwarf galaxies suggest the presence of large-scale magnetic fields. However the size and slow rotation of these galaxies appear insufficient to support a mean-field dynamo action to excite such fields. Here we suggest a new…