Instabilities in non-expanding glasma

TL;DR

This paper explores the complex instabilities in a non-expanding glasma, revealing how primary Nielsen-Olesen instabilities can generate secondary instabilities through azimuthal magnetic fields, explaining observed simulation behaviors.

Contribution

It introduces a new understanding of how primary instabilities lead to secondary ones via generated magnetic fields in non-expanding glasma.

Findings

Unstable modes grow exponentially and generate azimuthal magnetic fields.

Secondary instabilities can grow faster than primary ones at high momenta.

The results explain the interplay of instabilities in real-time glasma simulations.

Abstract

A homogeneous color magnetic field is known to be unstable for the fluctuations perpendicular to the field in the color space (the Nielsen-Olesen instability). We argue that these unstable modes, exponentially growing, generate an azimuthal magnetic field with the original field being in the z-direction, which causes the Nielsen-Olesen instability for another type of fluctuations. The growth rate of the latter unstable mode increases with the momentum p_z and can become larger than the former's growth rate which decreases with increasing p_z. These features may explain the interplay between the primary and secondary instabilities observed in the real-time simulation of a non-expanding glasma, i.e., stochastically generated anisotropic Yang-Mills fields without expansion.