Dielectric and Magnetic Materials and Boundary Conditions

Abstract

We have so far considered only electromagnetic fields in vacuum, in order not to obscure the most essential features of the theory by details associated with properties of matter. However, some interesting physical effects, and many of the most important practical applications result from the electromagnetic properties of matter. The interaction of matter with electric and magnetic fields derives from the fact that a material’s behavior observed at the macroscopic level depends strongly on its microscopic structure, and that matter is composed of charged particles. For example, the periodic properties of the elements are a consequence of the atomic electrons residing in nested sets of orbital shells (resulting from certain quantum mechanical rules). Electrons in the outermost (valence) shell also make the largest contribution to the electrical properties of materials. Exact treatment of these topics requires detailed knowledge of condensed matter physics, including quantum theory, and is beyond the scope of this book. Instead, this chapter is limited to an empirical, mostly macroscopic, treatment of Maxwell’s equations applied to dielectric and magnetic materials. We will restrict ourselves to low energies and low frequencies (adiabatic variations).

I Sing the Body Electric. Walt Whitman Leaves of Grass

Nature cannot be ordered about, except by obeying her. Francis Bacon Novum Organum (1620)