Axion magnetohydrodynamics and reconnection-driven axion bursts

TL;DR

This paper develops a non-ideal axion magnetohydrodynamics framework showing how magnetic reconnection can generate transient axion bursts in astrophysical environments like neutron stars.

Contribution

It introduces a first-principles formulation of axion MHD including axion inertia and reveals reconnection-driven axion emission mechanisms.

Findings

Magnetic reconnection excites mixed Alfvén-axion modes.

Reconnection leads to transient axion bursts in magnetars.

The mechanism offers a new observational window for axion detection.

Abstract

We formulate axion magnetohydrodynamics beyond the ideal limit, retaining axion inertia and the essential physics of non-ideal plasmas from first principles. In this framework, regions where magnetic flux freezing breaks down acquire a new physical role: whenever $\mathbf{E} \cdot\ \mathbf{B} \neq 0$, magnetic dissipation acts as a localized source of axion radiation. We show that magnetic reconnection naturally excites mixed Alfv\'en-axion modes, enabling coherent energy exchange between magnetic fields and axions in magnetically dominated environments. In neutron stars and magnetars, this mechanism leads generically to transient axion bursts powered by reconnection--driven Alfv\'enic dissipation. We connect this production process to observational prospects and derive a characteristic sensitivity to the axion--photon coupling, complementary to searches based on static magnetic fields.