The radiation emitted from axion dark matter in a homogeneous magnetic field, and possibilities for detection

TL;DR

This paper derives the analytical expression for axion-induced radiation in a magnetic field and proposes a detection scheme that could surpass current constraints for axion masses in the nano-electronvolt to micro-electronvolt range.

Contribution

It provides a new analytical model for axion-induced radiation in a cylindrical magnetic field and suggests a novel detection scheme with enhanced sensitivity.

Findings

Radiation power depends on magnetic field volume and axion mass in the long wave limit.

Peak power occurs at specific axion masses related to the cylinder radius.

Detection scheme can potentially exceed existing constraints for certain axion mass ranges.

Abstract

We study the direct radiation excited by oscillating axion (or axion-like particle) dark matter in a homogenous magnetic field and its detection scheme. We concretely derive the analytical expression of the axion-induced radiated power for a cylindrical uniform magnetic field. In the long wave limit, the radiation power is proportional to the square of the B-field volume and the axion mass $m_a$, whereas it oscillate as approaching the short wave limit and the peak powers are proportional to the side area of the cylindrical magnetic field and $m_a^{-2}$. The maximum power locates at mass $m_a\sim\frac{3\pi}{4R}$ for fixed radius $R$. Based on this characteristic of the power, we discuss a scheme to detect the axions in the mass range $1-10^4$\,neV, where four detectors of different bandwidths surround the B-field. The expected sensitivity for $m_a\lesssim1\,\mu$eV under typical-parameter values can far exceed the existing constraints.