4 research outputs found
The interrelation between the generation of large-scale electric fields and that of large-scale magnetic fields during inflation
The interrelation between the generation of large-scale electric fields and
that of large-scale magnetic fields due to the breaking of the conformal
invariance of the electromagnetic field in inflationary cosmology is studied.
It is shown that if large-scale magnetic fields with a sufficiently large
amplitude are generated during inflation, the generation of large-scale
electric fields is suppressed, and vice versa. Furthermore, a physical
interpretation of the result and its cosmological significance are considered.Comment: 12 pages, no figure, title changed, typos correcte
Primordial magnetic fields from second-order cosmological perturbations: Tight coupling approximation
We explore the possibility of generating large-scale magnetic fields from
second-order cosmological perturbations during the pre-recombination era. The
key process for this is Thomson scattering between the photons and the charged
particles within the cosmic plasma. To tame the multi-component interacting
fluid system, we employ the tight coupling approximation. It is shown that the
source term for the magnetic field is given by the vorticity, which signals the
intrinsically second-order quantities, and the product of the first order
perturbations. The vorticity itself is sourced by the product of the
first-order quantities in the vorticity evolution equation. The magnetic fields
generated by this process are estimated to be Gauss on the
horizon scale at the recombination epoch. Although our rough estimate suggests
that the current generation mechanism can work even on smaller scales, more
careful investigation is needed to make clear whether it indeed works in a wide
range of spatial scales.Comment: 10pages, minor corrections, accepted for publication in Class. Quant.
Gra