Amplification of mean magnetic field and magnetic helicity production in hot lepton plasma of early universe

We argue that the magnetic helicity conservation is violated at the lepton stage in the evolution of early Universe owing to the parity violation in the Standard Model of electroweak interactions. As a result, a cosmological magnetic field which can be a seed for the galactic dynamo obtains from the beginning a substantial magnetic helicity which has to be taken into account in the magnetic helicity balance at the later stage of galactic dynamo. The particle physics mechanism suggested in our works depends neither on helicity of matter turbulence with plasma vortices resulting in the standard α effect in dynamo theory nor on general rotation. The mechanism can result in a self-exitation of an (almost) uniform cosmological magnetic field. The text was submitted by the authors in English.     

Mirror Magnetic Field and Its Impact on Dark Matter Distribution in Galaxies

Journal of Experimental and Theoretical Physics - We obtain the value of the mirror magnetic field during different stages of cosmological evolution. We consider the magnetic field generation in...     

Large-scale magnetic field generation by alpha effect driven by collective neutrino-plasma interaction

We suggest a new mechanism for the generation of a large-scale magnetic field in the hot plasma of the early Universe which is based on parity violation in weak interactions and depends neither on the helicity of matter turbulence resulting in the standard alpha effect nor on general rotation. The mechanism can result in a self-excitation of an (almost) uniform cosmological magnetic field.     

Stiff magnetofluid cosmological model

We intestigate the behavior of the magnetic field in a cosmological model filled with a stiff perfect fluid in general relativity. The magnetic field is due to an electric current along thex axis. The behavior of the model when a magnetic field is absent is also discussed.     

Some Magnetized Bulk Viscous String Cosmological Models in Cylindrically Symmetric Inhomogeneous Universe with Variable ∧-Term

Some cylindrically symmetric inhomogeneous viscous fluid string cosmological models with magnetic field and cosmological term A varying with time are investigated. To get the deterministic solution, it has been assumed that the expansion （θ） in the model is proportional to the eigen value σ^11 of the shear tensor σ^ij. The value of cosmological constant for the model is found to be small and positive, which is supported by the results from recent supernovae Ia observations. The effect of bulk viscosity is to produce a change in perfect fluid and hence exhibits essential influence on the character of the solution. The physical and geometric properties of the models are also discussed in presence and absence of magnetic field.     

Inhomogeneous Bulk Viscous Fluid Universe with Electromagnetic Field and Variable Λ-Term

Cylindrically symmetric inhomogeneous cosmological model for bulk viscous fluid distribution with electromagnetic field is obtained. The source of the magnetic field is due to an electric current produced along the z-axis. F₁₂ is the non-vanishing component of electromagnetic field tensor. To get the deterministic solution, it has been assumed that the expansion θ in the model is proportional to the shear σ. The values of cosmological constant for these models are found to be small and positive at late time, which are consistent with the results from recent supernovae Ia observations. Physical and geometric aspects of the models are also discussed in presence and absence of magnetic field.     

An anisotropic magnetized viscous fluid cosmological model in general relativity

We investigate the behavior of a magnetic field in a viscous fluid cosmological model where the free gravitational field is of Petrov type D and the coefficient of shear viscosity is proportional to the rate of expansion in the model. Also discussed are the behavior of the model when the magnetic field tends to zero and some other physical properties.     

Qualitative magnetic cosmology

The technique of phase plane analysis, which was used in a previous paper [4] to study the behaviour of a class of perfect-fluid anisotropic cosmological models, is applied to some simple anisotropic models that contain a uniform magnetic field. A formal correspondence is established between these magnetic models (of Bianchi type I) and certain perfect fluid models (of Bianchi type II), and new exact solutions are consequently discovered.     

Magnetized anisotropic cosmological models with varying Λ

Some anisotropic homogeneous cosmological models with electromagnetic field are obtained in presence of a perfect fluid. The source of the magnetic field is due to an electric current produced along the x-axis. Without assuming any ad hoc law, we obtain a cosmological constant as a decreasing function of time which is supported by results from recent supernovae Ia observations. The behaviour of the electromagnetic field tensor together with some physical aspects of the model are also discussed.     

Some exact solutions of string cosmology in Bianchi III space-time

Following the techniques used by Letelier and Stachel some exact Bianchi III cosmological solutions of massive strings in the presence of magnetic field are obtained and their physical features are discussed. Some string solutions in which magnetic fields are absent are also discussed.     

Bianchi Type-I Model with Cosmic String in the Presence of a Magnetic Field: Spinor Description

A Bianchi type-I cosmological model in the presence of a magnetic flux along a cosmic string is investigated. A nonlinear spinor field is used to simulate the cosmological cloud of strings. It is shown that the spinor field simulation offer the possibility to solve the system of Einstein’s equation without any additional assumptions. It is pointed out that the present model is nonsingular at the end of the evolution and does not allow the anisotropic Universe to turn into an isotropic one.     

Simulation studies of the magnetic field generation in cosmological plasmas

We present computer simulation studies of the magnetic field generation by colliding electron clouds in cosmic plasmas. Simulation results exhibit purely growing magnetic fields, generation of electrostatic waves and subsequent electron energization in different regimes. The linear growth and saturated magnetic fields in our simulations are in good agreement with recent theoretical predictions of the Weibel instability induced magnetic fields in cosmological plasmas.     

String Cosmological Models with Magnetic Field

A new class of string cosmological models withand without magnetic field in the context of aspace-time with G₃ symmetry has beenpresented. In order to study the effects of magneticfield, the standard energy-momentum tensor is modified byincorporating additional term due to magnetic field. Thephysical and kinematical behaviours of the stringcosmological models have been discussed.     

Bianchi .Type-I Massive String Magnetized Barotropic Perfect Fluid Cosmological Model in General Relativity

Bianchi type-I massive string cosmological model with magnetic field of barotropic perfect fluid distribution through the techniques used by Latelier and Stachel is investigated. To obtain the deterministic model of the universe, it is assumed that the universe is filled with barotropic perfect fluid distribution. The magnetic field is due to electric current produced Mong the x-axis with infinite electrical conduictivity. The behaviour of the model in the presence and absence of magnetic field together with other physical aspects is further discussed.     

Gradient models of the axion–photon coupling

We establish an extended version of the Einstein–Maxwell-axion model by introducing into the Lagrangian cross-terms, which contain the gradient four-vector of the pseudoscalar (axion) field in convolution with the Maxwell tensor. The gradient model of the axion–photon coupling is applied to cosmology: we analyze the Bianchi-I type Universe with an initial magnetic field, electric field induced by the axion–photon interaction, cosmological constant and dark matter, which is described in terms of the pseudoscalar (axion) field. Analytical, qualitative and numerical results are presented in detail for two distinguished epochs: first, for the early Universe with magnetic field domination; second, for the stage of late-time accelerated expansion.     

Stationary rotating string world models with a magnetic field

Following the techniques used by Letelier and Stachel some new physically relevant stationary solutions of string cosmology with magnetic field are presented. In these solutions, the flow vector of matter has non-zero rotation and the cosmological constant is taken to be non-zero. Previously known solutions are derived as particular cases from our class of solutions. Some string models with vanishing cosmological constant are also discussed.     

Thick Domain Walls Coupled with Viscous Fluid and Electromagnetic Field in Lyra Geometry

In this paper, we have obtained plane symmetric cosmological models of thick domain walls with viscous field coupled with electromagnetic field in the framework of Lyra geometry, by using equation of state. Physical and geometrical implications of the models are also discussed in the presence of magnetic field.     

A class of stationary charged dust solutions of Einstein's field equations

We consider a special class of stationary rotating charged dust solutions of Einstein's field equations without cosmological constant. In these space-times, the motion of freely falling particles and of light rays can be visualized by the motion of charged particles in an appropriate model magnetic field. Any curl-free magnetostatic field, given on an open subset of Euclidean 3-space, can serve as a model magnetic field for a charged dust solution in this sense. The simplest example, corresponding to a homogeneous model magnetic field, is given by Som-Raychaudhuri space-time. Some other examples are worked out.     

TeV γ-ray astronomy

The TeV γ-ray sky displays at this time 9 sources comprising 6 supernova remnants (SNR) and 3 active galactic nuclei (AGN). They have been discovered with AIR ERENKOV TELESCOPES since 1989, and more sources are sure to be found. They are related to violent astrophysical events and promise to be used as unique tools for cosmological questions like the universal infrared photon field and the intergalactic magnetic field strength.     

Anisotropic Plane Symmetric Magnetized Model with Cosmological Constant

In this paper, we have obtained the solutions of perfect fluid cosmological model in Cylindrically-symmetric space time (Marder in Proc. R. Soc. A 246:133, 1958) with varying cosmological constant in the presence of electromagnetic field. To get determinate model of the universe we assumed that the scalar of expansion in the model is proportional to the eigen-value of the shear tensor which lead to the condition A=(BC) ⁿ . The magnetic field is due to an electric current produced along x-axis. Thus the magnetic field is in yz-plane and F ₂₃ is the only non-vanishing component of electromagnetic field tensor F _ij . Various physical and geometrical features of the model have been discussed.