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Simulating axion electrodynamics in magnetized plasmas: Energy transfer in the inhomogeneous and strongly varying limit

Fabrizio Corelli1,2,*, Estanis Utrilla Ginés3, Enrico Cannizzaro4,†, Andrea Caputo1,5,6,‡, and Samuel J. Witte7,8,9,§

  • *Contact author: fabrizio.corelli@aei.mpg.de
  • †Contact author: enrico.cannizzaro@tecnico.ulisboa.pt
  • ‡Contact author: andrea.caputo@cern.ch
  • §Contact author: Samuel.Witte@physics.ox.ac.uk
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Phys. Rev. D 114, 083021 – Published 7 October, 2026

DOI: https://doi.org/10.1103/4vhw-kc8c

Abstract

In this work, we study the electromagnetic response induced by axions in a magnetized plasma, focusing specifically on characterizing energy transfer and energy losses from the ambient axion field in highly inhomogeneous and strongly varying backgrounds. Using a suite of both frequency-domain and time-domain simulations, we solve for the efficiency of photon excitation in a rapidly varying background; the indirect excitation of Alfvén modes, occurring when a Langmuir-Ordinary (LO) mode is resonantly excited near a combined cutoff-resonance of the dispersion relations of the LO and Alfvén modes; and the excitation of electric fields in small localized plasma underdensities. We identify a particularly interesting regime in which energy can be transferred into subluminal plasma modes (ω<k) with an efficiency greater than that of superluminal modes (ω>k). Our results highlight a variety of less conventional ways in which axions (and other light degrees of freedom that mix with electromagnetism, such as dark photons or gravitons) can interact in extreme astrophysical environments.

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Phys. Rev. D 114, 083021– Published 7 October, 2026
  • Received 3 April 2026
  • Accepted 9 September 2026
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