Chiral Effects and Cosmic Magnetic Fields

TL;DR

This paper investigates how cosmic chiral asymmetry influences the generation and evolution of magnetic fields in the early universe, revealing attractor solutions that produce strong, helical magnetic spectra.

Contribution

It incorporates chiral effects into magnetic field equations and demonstrates their impact through analytical and numerical solutions, highlighting the formation of peaked, helical magnetic spectra.

Findings

Chiral effects lead to a Gaussian peak in the magnetic spectrum.

Magnetic fields become maximally helical due to chiral effects.

Spectrum peaks shift to longer scales and sharpen over time.

Abstract

In the presence of cosmic chiral asymmetry, chiral-vorticity and chiral-magnetic effects can play an important role in the generation and evolution of magnetic fields in the early universe. We include these chiral effects in the magnetic field equations and find solutions under simplifying assumptions. Our numerical and analytical results show the presence of an attractor solution in which chiral effects produce a strong, narrow, Gaussian peak in the magnetic spectrum and the magnetic field becomes maximally helical. The peak in the spectrum shifts to longer length scales and becomes sharper with evolution. We also find that the dynamics may become non-linear for certain parameters, pointing to the necessity of a more complete analysis.