Sources and Electrodynamics

A new kind of particle theory is being explored, one that is intermediate in concept between the extremes of $S$ matrix and field theory. It employs the methods of neither approach. There are no operators, and there is no appeal to analyticity in momentum space. It is a phenomenological theory, and cognizant that measurements are operations in space and time. Particles are defined realistically by reference to their creation or annihilation in suitable collisions. The source is introduced as an abstraction of the role played by all the other particles involved in such acts. Through the use of sources the production and detection of particles, as well as their interaction, are incorporated into the theoretical description. There is a creative principle that replaces the devices of other formulations. It is an insistence upon the generality of the space-time description of the coupling among sources that is inferred from a specific spatio-temporal arrangement, in which various particles propagate between sources. Standard quantum-mechanical and relativistic requirements, imposed on the source description of noninteracting particles, imply the existence of the two statistics and the connection with spin. In this situation sources are only required to emit and absorb the mass of the corresponding particle. Particle dynamics is introduced by an extension of the source concept. It is considered meaningful for a source to emit several particles with the same total quantum numbers as a single particle, if sufficient mass is available. This is most familiar as the photon radiation that accompanies the emission of charged particles. The new types of sources introduced in this way imply new couplings among sources, which supply still further varieties of sources. This proliferation of interactions spans the full dynamical content of the initial primitive interaction. The ambition of the phenomenological source theory is to represent all dynamical aspects of particles, within a certain context, by a suitable primitive interaction. This paper is devoted to the reconstruction of electrodynamics.