The Physical Dipole Model and Polarizability for Magnetostatic Object Parameter Estimation

Abstract

The physical dipole is the next simplest model of a magnetic object beyond the point dipole model. The theory and analytical properties of the physical dipole are developed and explored, and compare favorably with alternative models, including limiting cases of prolate spheroids and other shapes. The general applicability of explicitly modeling the demagnetization properties of magnetic materials is critically reviewed, and reasons proffered to use the object polarizability instead, especially for the external field properties of most relevance. Neither the physical dipole model nor polarizability is currently used for magnetostatic parameter estimation of magnetic objects such as unexploded ordnance. It is recommended that their utility be further explored with field data.