A. INTERPRETATION OF RELATIVISTIC FORCE DENSITY IN MOVING POLARIZABLE AND MAGNETIZABLE MEDIA

We are developing the fundamental equations of electrodynamics (for both electro-magnetism and dynamics) of moving and deforming material, especially dielectric and magnetic material. The ultimate goal is the determination of the macroscopic force acting on a continuum, and the distribution of that force as a function of space and time. The fundamental equations must be consistent with (a) the special theory of relativity; (b) electromagnetism of free space; (c) electromagnetism of stationary bodies; (d) relativistic continuum mechanics of solids or fluids without electromagnetic fields; (e) thermodynamic measurements of the various kinds of power flow; and (f) nonlinear material properties. Thus far we have obtained equations for nondisper-sive conservative media. Work is now in progress on media showing dispersion both in time and/or space. We intend to extend the equations to irreversible phenomena. Also, the connection between the equations for nonlinear media and their corresponding small-signal formulation will be explored. Use of these equations in specific situations is contemplated (a) to illustrate the equations and the various approximations, and (b) to predict novel effects, with a view toward testing for these effects experimentally