Cosmic Electromagnetic Fields due to Perturbations in the Gravitational Field
arXiv:1203.6032 · doi:10.1103/PhysRevD.86.083533
Abstract
We use non-linear gauge-invariant perturbation theory to study the interaction of an inflation produced seed magnetic field with density and gravitational wave perturbations in an almost Friedmann-Lemaître-Robertson-Walker (FLRW) spacetime. We compare the effects of this coupling under the assumptions of poor conductivity, infinite conductivity and the case where the electric field is sourced via the coupling of velocity perturbations to the seed field in the ideal magnetohydrodynamic (MHD) regime, thus generalizing, improving on and correcting previous results. We solve our equations for long wavelength limits and numerically integrate the resulting equations to generate power spectra for the electromagnetic field variables, showing where the modes cross the horizon. We find that the rotation of the electric field dominates the power spectrum on small scales, in agreement with previous arguments.
16 pages, 3 figures, published in PRD
References in corpus (9)
- xPerm: fast index canonicalization for tensor computer algebra
- Cosmology with inhomogeneous magnetic fields
- Cosmological Magnetic Field: a fossil of density perturbations in the early universe
- Cosmological magnetic fields from nonlinear effects
- Primordial magnetic fields from second-order cosmological perturbations: Tight coupling approximation
- On inhomogeneous magnetic seed fields and gravitational waves within the MHD limit
- A Cautionary Note on Cosmological Magnetic Fields
- Response to ``Comment on `Primordial magnetic seed field amplification by gravitational waves' "
- On constraint-consistency, covariant operators, gauge-invariance, etc