Chaotic flows and cosmic dynamos in anisotropic pseudo-Riemannian four-dimensional spacetime

TL;DR

This paper investigates the feasibility of cosmic dynamos in anisotropic Bianchi type IX and Kasner universes, analyzing magnetic field amplification under various cosmological conditions and constraints.

Contribution

It introduces a model where only one expansion direction persists in Bianchi IX universes, enabling magnetic field amplification consistent with observational bounds.

Findings

Magnetic fields can amplify from 10^{-6}G to 10^{-5}G in certain anisotropic models.

Rotation constraints from CMB data limit the dynamo effectiveness in Bianchi IX models.

Chaotic flows in pseudo-Riemannian spacetime can sustain magnetic field amplification.

Abstract

It is shown that the existence of the cosmic kinematic fast dynamos in Bianchi type IX rotating cosmological models, faces severe difficulties, due to the fact that in these models rotation increases without bounds, which is strictly forbidden by CMB astronomical date which imposes strong bounds on its rotation with respect with its rapid expansion. The only way out of this difficulty is to assume that at least one of the expansion directions of this anisotropic universe decays as fast as the amplification rate of primordial magnetic fields. A solution is found where only one direction of the anisotropic universe expands while the other two remain constants. We compute an amplification of the seed magnetic field in the case where Bianchi IX degenerates into de Sitter metric, fields amplify from 10^{-6}G to 10^{-5}G in spiral galaxies for a cosmological constant of the order $|{\Lambda}|<10^{33}s^{-2}$ and considering that the age of universe of the order of 10^{10}yrs. Another example is given by the ABC chaotic flows in the pseudo-Riemannian spacetime representing the Kasner anisotropic nonsingular universe.