Radiation of a nonrelativistic particle during its finite motion in a central field

Abstract

The spectrum and expressions for the intensity of dipole radiation lines are obtained for a classical nonrelativistic charged particle that executes a finite aperiodic motion in an arbitrary central field along a non-closed trajectory. It is shown that, in this case of a conditionally periodic motion, the radiaton spectrum consists of two series of equally spaced lines. It is pointed out that, according to the correspondence principle, the rise of two such series in the classical theory corresponds to the well-known selection rule |Δl| = 1 for the dipole radiation in a central field in quantum theory, where l is the orbital angular momentum of the particle. The results obtained can be applied to the description of the radiation and the absorption of a classical collisionless electron plasma in nanoparticles irradiated by an intense laser field. As an example, the rate of collisionless absorption of electromagnetic wave energy in equilibrium isotropic nanoplasma is calculated.