The first magnetic fields in the universe

TL;DR

This paper proposes that the initial cosmic structures can generate magnetic fields spontaneously through a first dynamo process, eliminating the need for primordial seed fields, and suggests a method for simulating this phenomenon.

Contribution

It introduces the concept of a first dynamo driven by plasma instabilities that can be modeled with magnetohydrodynamics, enabling numerical studies of early magnetic field formation.

Findings

First structures can generate magnetic fields without primordial seeds.

A simple approach to MHD modeling of plasma instabilities is proposed.

Potential for numerical simulations of early universe magnetic fields.

Abstract

We show that the first structures that form in the universe should spontaneously generate magnetic fields. No primordial seed field is required for this "first dynamo". Although the first dynamo starts with kinetic plasma instabilities, we argue that an adequate magnetohydrodynamic description might be possible via a simple trick. This should allow a numerical study of the effect of the first magnetic fields on the first baryonic objects.