The Origin of Magnetic Fields in Galaxies

TL;DR

This paper proposes that primordial plasma fluctuations, as predicted by the Fluctuation-Dissipation-Theorem, can naturally generate the observed microgauss magnetic fields in galaxies within a billion years.

Contribution

It introduces a model based on primordial plasma fluctuations to explain the origin of galactic magnetic fields, linking fundamental physics to astrophysical observations.

Findings

Predicted magnetic field strength of ~0.034 μG in 0.3 kpc regions.

Fields over >0.34 kpc regions can reach microgauss levels if fluctuations are not random.

Model explains magnetic field origins within 10^9 years in high-redshift galaxies.

Abstract

Microgauss magnetic fields are observed in all galaxies at low and high redshifts. The origin of these intense magnetic fields is a challenging question in astrophysics. We show here that the natural plasma fluctuations in the primordial universe (assumed to be random), predicted by the Fluctuation-Dissipation-Theorem, predicts $\sim 0.034 \mu G$ fields over $\sim 0.3$ kpc regions in galaxies. If the dipole magnetic fields predicted by the Fluctuation-Dissipation-Theorem are not completely random, microgauss fields over regions $\gtrsim 0.34$ kpc are easily obtained. The model is thus a strong candidate for resolving the problem of the origin of magnetic fields in $\lesssim 10^{9}$ years in high redshift galaxies.