Eur. Phys. J. Spec. Top.
https://doi.org/10.1140/epjs/s11734-025-01469-3

Regular Article

Polarization effects in cosmic-ray acceleration by cyclotron autoresonance

¹ Department of Physics, American University of Sharjah, POB 26666, Sharjah, United Arab Emirates
² Ministry of Education Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter, Shaanxi Province Key Laboratory of Quantum Information and Quantum Optoelectronic Devices, School of Physics, Xi’an Jiaotong University, 710049, Xi’an, China

^a ysalamin@aus.edu

Received: 11 November 2024
Accepted: 13 January 2025
Published online: 24 January 2025

Abstract

Employing a two-parameter model for representing the radiation field, the theory of cosmic-ray acceleration by cyclotron autoresonance is analytically generalized here to include any state of polarization. The equations are derived rigorously and used to investigate dynamics of the nuclides $_1^{}$H$_{}^1$, $_2^{}$He$_{}^4$, $_{26}^{}$Fe$_{}^{56}$, and $_{28}^{}$Ni$_{}^{62}$, in severe astrophysical conditions. Single-particle calculations and many-particle simulations show that these nuclides can reach ZeV energies ($1ZeV={10}^{21}$ eV) due to interaction with superintense radiation of wavelengths $\lambda =1$ and $10\mathrm{\mu }$m, and $\lambda =50$ pm, and magnetic fields of strengths at the mega- and gigatesla levels. Examples employing radiation intensities in the range ${10}^{32}-{10}^{42}$ W/m$_{}^2$ are discussed and radiation loss by the accelerated particles is shown to be small over large excursion distances.