Chiral Magnetohydrodynamic Turbulence

TL;DR

This paper investigates how chiral anomaly effects influence magnetohydrodynamic turbulence, showing they can enhance inverse cascade processes, sustain magnetic fields longer, and promote the growth of correlation lengths in the early universe.

Contribution

It introduces a theoretical framework incorporating chiral anomaly effects into MHD turbulence, demonstrating their role in magnetic field evolution and inverse cascade enhancement.

Findings

Chiral effects can generate maximally-helical fields from non-helical initial conditions.

Chiral anomaly effects slow magnetic field decay over time.

Chiral effects promote faster growth of magnetic correlation length.

Abstract

In this work the influence of the chiral anomaly effect on the evolution of magnetohydrodynamic turbulence was studied. We argue that in the early universe, before the electroweak symmetry breaking, and for temperatures high enough such that the electron mass can be ignored, the description of a charged plasma in general needs to take into account the interplay between turbulence and the anomaly effects. It was demonstrated that this generalization can have important consequences on the evolution of turbulence, leading to the creation of maximally-helical fields from initially non-helical ones. Therefore, chiral effects can strongly support turbulent inverse cascade, and lead to a slower decrease of the magnetic field with time, and also to a faster growth of the correlation length, when compared to the evolution predicted by the standard magnetohydrodynamical description. Using the weak anomaly approximation, and treating the anomaly contributions to magnetic energy and helicity as a small perturbation, we derive the specific solutions for the inverse cascade regime that demonstrate how chiral effects support the inverse cascade.