Cyclotron auto-resonance for cosmic-ray acceleration to ZeV energies

Highlights: • Cyclotron auto-resonance acceleration of cosmic rays is generalized to cover any arbitrary elliptical polarization state. • It is shown that left-circularly polarized EM waves result in optimal acceleration. • Many-particle simulation results are presented to support the single-particle calculation results. Equations are derived here for the dynamics of particles undergoing cyclotron autoresonance acceleration in which elliptically-polarized plane-wave radiation fields are employed. The equations are used to study the acceleration of bare atomic nuclei in astrophysical environments by performing single-particle calculations, supported by many-particle simulations. It is shown that the nuclides ₁H¹, ₂He⁴, ₂₆Fe⁵⁶, and ₂₈Ni⁶², can reach ZeV energies in the presence of superintense radiation and megatesla magnetic fields. Nuclides of any species are shown to attain maximum kinetic energy from interaction with an integer number of phase cycles of left circularly-polarized radiation.