Magnetogenesis by Wave-Driven Momentum Exchange

TL;DR

This paper introduces a novel mechanism where wave-driven momentum exchange among plasma species can generate magnetic fields rapidly, surpassing traditional astrophysical seed field methods like the Biermann battery.

Contribution

It reveals a new wave-driven process for magnetic field generation in plasmas, highlighting its potential significance in astrophysical contexts.

Findings

Momentum exchange can induce curl in electric fields.

Generated magnetic fields can grow faster than Biermann battery.

Mechanism operates on magnetohydrodynamic timescales.

Abstract

When multiple species interact with an electrostatic ion acoustic wave, they can exchange momentum, despite the lack of momentum in the field itself. The resulting force on the electrons can have a curl, and thus give rise to compensating electric fields with curl on magnetohydrodynamic timescales. As a result, a magnetic field can be generated. Surprisingly, in some astrophysical settings, this mechanism can seed magnetic fields with growth rates even larger than through the traditional Biermann battery.