Photon transport theory

Abstract

A first order, momentum-configuration space transport equation for photons is derived for low energy (nonrelativistic) systems. The derivation is first order in the sense that the transition probabilities characterizing photon scattering emission and absorption are computed only to the first nonvanishing order by conventional perturbation methods.The present approach provides an essentially axiom-deduction development of the theory of radiative transfer (albeit via several ill-evaluated approximations) within the context of which various processes and their interrelationships may be investigated. Most of these processes have hitherto been studied only phenomenologically and usually piecemeal. Specific application to photon scattering, cyclotron radiation, recombination radiation, de-excitation radiation, and bremsstrahlung is made in the test.The derivation of an H-theorem for photon-particle systems is sketched; and contact is made with the usual statistical mechanical treatment of the equilibrium states of such systems.It is also shown that some aspects of collective particle behavior can be introduced quite naturally into the description of photon transport in the fully ionized plasma.