2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/153325Some considerations of long wavelength and broadband radiation sources based on the emission of the coherent radiation by a train of short relativistic electron bunches moving in an open resonator along an arc-like or undulator trajectories and some new versions of the transition radiation sources and long wavelength sources based on storage rings are presented.30 pages, LaTeX, Preprint FIAN No 35, 1996Classical Physicstext