Effective chiral magnetic currents, topological magnetic charges, and microwave vortices in a cavity with an enclosed ferrite disk

TL;DR

This paper explores how a ferrite disk in a microwave cavity creates complex electromagnetic vortices, chiral magnetic currents, and topological charges due to gyrotropy and geometry, analyzed through numerical simulations.

Contribution

It introduces a novel analysis of microwave vortices using magnetic currents and reveals symmetry-breaking effects leading to chiral magnetic phenomena.

Findings

Microwave vortices are characterized by equivalent magnetic currents.

Gyrotropy and geometry induce symmetry breaking and topological charges.

Precessing electric dipole polarization observed inside the ferrite disk.

Abstract

In microwaves, a TE-polarized rectangular-waveguide resonator with an inserted thin ferrite disk gives an example of a nonintegrable system. The interplay of reflection and transmission at the disk interfaces together with the material gyrotropy effect gives rise to whirlpool-like electromagnetic vortices in the proximity of the ferromagnetic resonance. Based on numerical simulation, we show that a character of microwave vortices in a cavity can be analyzed by means of consideration of equivalent magnetic currents. Maxwell equations allows introduction of a magnetic current as a source of the electromagnetic field. Specifically, we found that in such nonintegrable structures, magnetic gyrotropy and geometrical factors leads to the effect of symmetry breaking resulting in effective chiral magnetic currents and topological magnetic charges. As an intriguing fact, one can observe precessing behavior of the electric-dipole polarization inside a ferrite disk.