Monopole magnetohydrodynamics on a plane: Magnetosonic waves and dynamo instability

TL;DR

This paper explores magnetohydrodynamics in a two-dimensional condensed matter context with emergent monopoles, revealing isotropic magnetosonic waves and a dynamo mechanism influenced by system compressibility.

Contribution

It introduces the concept of 2D magnetohydrodynamics with monopoles, identifying magnetosonic waves and dynamo effects unique to this lower-dimensional setting.

Findings

Identification of isotropic magnetosonic waves in 2D MHD.

Discovery of a dynamo mechanism requiring flow compressibility.

Role of odd viscosity in wave propagation.

Abstract

Condensed matter systems can host emergent `vacua' with particles, fields and dimension different from that of the universe we inhabit. Motivated by the appearance of emergent gauge fields with both electric and magnetic charges, we consider the fate of electromagnetism in two dimensions in the presence of magnetic monopoles. We find that generically electromagnetic fields are damped due to resistive effects. However, we can still identify a magnetohydrodynamic regime. It exhibits magnetosonic waves which, unlike in $d=3$, are isotropic, to which there is a contribution from the odd viscosity coefficient present in the system. Further, we find a dynamo action, which unlike in $d=3$ requires compressibility of the flow.