Electrodynamics of Magnetoelectric Media and Magnetoelectric Fields

Abstract

The relationship between magnetoelectricity and electromagnetism is a subject of a strong interest and numerous discussions in microwave and optical wave physics and material sciences. The definition of the energy and momentum of the electromagnetic (EM) field in a magnetoelectric (ME) medium is not a trivial problem. The question of whether electromagnetism and magnetoelectricity can coexist without an extension of Maxwell's theory arises when the effects of EM energy propagation are studied and the group velocity of the waves in an ME medium is considered. The energy balance equation reveals unusual topological structure of fields in ME materials. Together with certain constraints on the constitutive parameters of a medium, definite constraints on the local field structure should be imposed. Analyzing the EM phenomena inside an ME material, the question “what kind of the near fields arising from a sample of such a material can be measured?” should be answered. The visualization of the ME states requires an experimental technique that is based on an effective coupling to the violation of spatial as well as temporal inversion symmetry. To observe the ME energy in a subwavelength region, it is necessary to assume the existence of first‐principle near fields—the ME fields. These are non‐Maxwellian near fields with specific properties of violation of spatial and temporal inversion symmetry. A particular interest to the ME fields arises in studies of metamaterials with “artificial‐atoms” ME elements.

Magnetoelectric Energy in Electrodynamics: Magnetoelectricity, Bi(an)isotropy, and Magnetoelectric Meta‐Atoms

“…This implies the presence of a power-flow circulation, which can be carried out with synchronous rotation in time of both complex-amplitude vectors E m i and H m j . [12,14] So, the process is accompanied by power-flow vortices in subwavelength domains. The power flows of the circulating adiabatic processes of the energy interchange are not exclusively the EM power flows.…”

“…So, the orbital angular momentum of the fields in the domain is half-integer. [14] This can be possible due to topological effects in subwavelength domains. For EM radiation, these domains are topological polarization singularities.…”

Magnetoelectric‐Field Electrodynamics: Search for Magnetoelectric Point Scatterers

“…( 9) implies that there exists a linear time-relation coupling between complex amplitudes of the fields. In a general form, we can write [14…”

“…In a subwavelength region where both the electric and magnetic fields exist, energy conversion between average stored energies E W , M W , and ME W can occur through a certain circular process of energy exchange. This implies the presence of a power-flow circulation, which can be carried out with synchronous rotation in time of both complex-amplitude vectors i m E and j m H [12,14]. So, the process is accompanied by power-flow vortices in subwavelength domains.…”