Introduction: scope and aims
There are two underlying themes in this book. The first concerns the use and application of the formally adjoint and the Lorentz-adjoint Maxwell system of equations, the latter so-called since it leads to the Lorentz reciprocity theorem. The (formally) adjoint Maxwell system is shown to play an essential role in the derivation of scattering theorems. With the aid of the adjoint wave fields in anisotropic and possibly absorbing media, one obtains a bilinear concomitant vector P, having zero divergence, which in the case of the Maxwell system turns out to be no more than a generalization of the Poynting vector and reduces to the time-averaged Poynting vector in loss-free media. Making use of normalized adjoint eigenmodes we may decompose an arbitrary wave field into its component eigenmodes, and a complex amplitude aα and its adjoint āα may be defined so that the algebraic sum of the products āαaα for all eigenmodes equals the component flux density P z of the generalized Poynting vector in a specified direction ž (normal to the stratification, for instance, in stratified media). These results are used in the derivation of scattering theorems (‘reciprocity in k-space’) for plane-stratified and curved-stratified anisotropic media (Chaps. 2 and 3), and in the generalization of a reciprocity theorem involving scattering from an arbitrary object immersed in a homogeneous or plane-stratified anisotropic absorbing medium (Chap. 7).
KeywordsWave Field Time Reversal Poynting Vector Reciprocity Theorem Chiral Medium
Unable to display preview. Download preview PDF.