Magnetic field in expanding quark-gluon plasma

TL;DR

This paper analyzes the magnetic field in expanding quark-gluon plasma, showing that plasma flow has minimal impact on the magnetic field, allowing separate studies of electromagnetic effects and plasma dynamics.

Contribution

It demonstrates that the plasma flow's effect on magnetic field is less than 10%, supporting the decoupling of plasma hydrodynamics and electromagnetic field evolution.

Findings

Magnetic field effect on plasma flow is less than 10%.

Plasma and magnetic field dynamics can be studied independently.

Magnetic wake in plasma is negligible.

Abstract

Intense electromagnetic fields are created in the quark-gluon plasma by the external ultra-relativistic valence charges. The time-evolution and the strength of this field are strongly affected by the electrical conductivity of the plasma. Yet, it has recently been observed that the effect of the magnetic field on the plasma flow is small. We compute the effect of plasma flow on magnetic field and demonstrate that it is less than 10\%. These observations indicate that the plasma hydrodynamics and the dynamics of electromagnetic field decouple. Thus, it is a very good approximation, on the one hand, to study QGP in the background electromagnetic field generated by external sources and, on the other hand, to investigate the dynamics of magnetic field in the background plasma. We also argue that the wake induced by the magnetic field in plasma is negligible.