Production of axion-like particles from photon conversions in large-scale solar magnetic fields

TL;DR

This paper investigates a new mechanism for axion-like particle production in the Sun via photon conversions in large-scale magnetic fields, providing updated bounds and detection prospects for future experiments.

Contribution

It introduces a novel calculation of solar ALP production through magnetic field-induced photon conversions, which was previously neglected.

Findings

Large-scale solar magnetic fields can significantly enhance ALP production.

New bounds on ALP-photon coupling are derived from energy-loss constraints.

Future helioscope experiments could detect this additional ALP flux.

Abstract

The Sun is a well-studied astrophysical source of axion-like particles (ALPs), produced mainly through the Primakoff process. Moreover, in the Sun there exist large-scale magnetic fields that catalyze an additional ALP production via a coherent conversion of thermal photons. We study this contribution to the solar ALP emissivity, typically neglected in previous investigations. Furthermore, we discuss additional bounds on the ALP-photon coupling from energy-loss arguments, and the detection perspectives of this new ALP flux at future helioscope and dark matter experiments.