Covariant hysteretic constitutive theory for Maxwell’s equations: application to axially rotating media

Abstract

This paper explores a class of non-linear constitutive relations for materials with memory in the framework of covariant macroscopic Maxwell theory. Based on earlier models for the response of hysteretic ferromagnetic materials to prescribed slowly varying magnetic background fields, generalized models are explored that are applicable to accelerating hysteretic magneto-electric substances coupled self-consistently to Maxwell fields. Using a parameterized model consistent with experimental data for a particular material that exhibits purely ferroelectric hysteresis when at rest in a slowly varying electric field, a constitutive model is constructed that permits a numerical analysis of its response to a driven harmonic electromagnetic field in a rectangular cavity. This response is then contrasted with its predicted response when set in uniform rotary motion in the cavity.

Keywords:

• hysteresis
• ferroelectricity
• ferromagnetism
• multiferroics
• electromagnetism
• constitutive theory
• differential geometry

Acknowledgments

The authors are members of the ALPHA-X collaboration funded by EPSRC and are also grateful for support from the Cockcroft Institute of Accelerator Science and Technology (STFC).