Related papers: Magnetic fields from reionisation
We discuss a model which can generate scale-invariant helical magnetic fields on large scales ($\lesssim 1$Mpc) in the primordial universe. It is also shown that the electric conductivity becomes significant and terminates magnetogenesis…
A variety of observations impose upper limits at the nano Gauss level on magnetic fields that are coherent on inter-galactic scales while blazar observations indicate a lower bound $\sim 10^{-16}$ Gauss. Such magnetic fields can play an…
The onset and evolution of magnetic fields in laboratory and astrophysical plasmas is determined by several mechanisms, including instabilities, dynamo effects and ultra-high energy particle flows through gas, plasma and interstellar-media.…
Magnetic-field generation by a relativistic ion beam propagating through an electron-ion plasma along a homogeneous magnetic field is investigated with 2.5D high-resolution particle-in-cell (PIC) simulations. The studies test predictions of…
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,…
Galactic cosmic rays are believed to be mostly accelerated at supernova shocks. However, the interstellar magnetic field is too weak to efficiently accelerate galactic cosmic rays up to the highest energies, i.e. $10^{15}$ eV. A stronger…
It is recently proposed that cosmic rays generate a seed magnetic field in the early universe. In this paper, we propose another generation mechanism of magnetic fields by cosmic rays, which is the Biermann battery driven by resistive…
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…
Very high energy gamma-rays are expected to be absorbed by the extragalactic background light over cosmological distances via the process of electron-positron pair production. Recent observations of cosmologically distant gamma-ray emitters…
Effect of guiding magnetic field on evolution of stimulated emission is considered. It is shown that the transverse dynamics of electrons contributes to generation process and that contribution decreases with the magnetic field grows. The…
We explore a novel process in the early Universe in which thermalized photons are converted into gravitons in the presence of strong primordial magnetic fields. It is found that the frequency of generated gravitational waves (GWs) is…
Sufficiently large seeds for generating the observed (inter)galactic magnetic fields emerge naturally in string cosmology from the amplification of electromagnetic vacuum fluctuations due to a dynamical dilaton background. The success of…
We show that axion-like particles that only couple to invisible dark photons can generate visible B-mode signals around the reionization epoch. The axion field starts rolling shortly before reionization, resulting in a tachyonic instability…
It is proposed to produce highly charged ions in the local potential traps formed by the rippled electron beam in a focusing magnetic field. In this method, the extremely high electron current densities can be attained on short length of…
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…
Cosmic strings are a type of cosmic defect formed by a symmetry-breaking phase transition in the early universe. Individual strings would have gathered to build a network, and their dynamical motion would induce scalar--, vector-- and…
We investigate graviton-photon oscillations sourced by cosmological magnetic fields from Gertsenshtein effect. We adopt a robust perturbative approach and we find that the conversion probability from graviton to photon can be resonantly…
Topological spin transport of electromagnetic waves (photons) in stationary smoothly inhomogeneous isotropic medium is studied. By diagonalizing photon kinetic energy in Maxwell equations we derive the non-Abelian pure gauge potential in…
Nonlinear dynamics creates vortical currents when the tight-coupling approximation between photons and baryons breaks down around the time of recombination. This generates a magnetic field at second order in cosmological perturbations,…
The explanation of the observed galactic magnetic fields may require the existence of a primordial magnetic field. Such a field may arise during the early cosmological phase transitions, or because of other particle physics related…