Chiral Magnetic Effect in Protoneutron Stars and Magnetic Field Spectral Evolution

TL;DR

This paper studies how the chiral magnetic instability in protoneutron stars influences magnetic field growth and spectral evolution during early cooling, potentially generating fields up to 10^{14} G depending on star conditions.

Contribution

It provides a detailed analysis of the magnetic power and helicity spectra resulting from the chiral magnetic instability in protoneutron stars, highlighting the dependence on temperature, density fluctuations, and turbulence.

Findings

Magnetic fields up to 10^{14} G can be generated during early cooling.

Magnetic field spectra concentrate around submillimeter to centimeter scales.

Field strength and structure depend on star's temperature and turbulence spectrum.

Abstract

We investigate the evolution of the chiral magnetic instability in a protoneutron star and compute the resulting magnetic power and helicity spectra. The instability may act during the early cooling phase of the hot protoneutron star after supernova core collapse, where it can contribute to the buildup of magnetic fields of strength up to the order of $10^{14}$ G. The maximal field strengths generated by this instability, however, depend considerably on the temperature of the protoneutron star, on density fluctuations and turbulence spectrum of the medium. At the end of the hot cooling phase the magnetic field tends to be concentrated around the submillimeter to cm scale, where it is subject to slow resistive damping.