Electromagnetic conversion into kinetic and thermal energies

TL;DR

This paper investigates how electromagnetic energy converts into kinetic and thermal energies during the early Universe's reheating phase, emphasizing the dominant role of electric energy dissipation over magnetic energy in this process.

Contribution

It demonstrates that electric energy dissipation primarily drives the conversion into magnetohydrodynamic energy during reheating, highlighting the importance of conductivity emergence timing.

Findings

Electric energy dissipation is the main driver of energy conversion.

Magnetic energy plays a secondary role in the process.

Significant electric energy can convert into magnetohydrodynamic energy if conductivity emerges early.

Abstract

Conversion of electromagnetic energy into magnetohydrodynamic energy occurs when the electric conductivity changes from negligible to finite values. This process is relevant during the epoch of reheating of the early Universe at the end of inflation and before the emergence of the radiation-dominated era. We find that conversion into kinetic and thermal energies is primarily the result of electric energy dissipation and that the magnetic energy plays only a secondary role in this process. This means that, since electric energy dominates over magnetic energy during inflation and reheating, significant amounts of electric energy can be converted into magnetohydrodynamic energy when conductivity emerges early enough, before the relevant length scales become stable.