In accordance with the preceding discussion, the theoretical foundation for describing electromagnetic scattering by particles and particle groups in this book is provided by classical macroscopic electromagnetics. This chapter is intended to summarize basic concepts and equations of electromagnetic theory that will be used extensively in the remainder of the book and introduce the necessary notation.

We start by formulating the primordial set of time-domain MMEs, constitutive relations, and boundary conditions. This is followed by a general analysis of time-harmonic fields and the frequency-domain MMEs. Finally, we discuss energy conservation in the framework of the frequency-domain macroscopic electromagnetics.

The macroscopic Maxwell equations and constitutive relations

As already mentioned, the basic laws of macroscopic electromagnetics are adopted in this textbook essentially as axioms describing the spatial distribution and temporal behavior of the electromagnetic field and its interaction with matter. A thorough justification of this approach can be found in the textbook by Roth-well and Cloud (2009). The microphysical derivation of the MMEs from more fundamental physical principles and the range of their validity are discussed by de Groot (1969), Robinson (1973), Akhiezer and Peletminskii (1981), Suttorp (1989), and Jackson (1998).