Relativistic electron beam interactions for generation of high power millimeter and submillimeter waves

The use of relativistic processes in nonneutralized electron beams is discussed. The electron beams may be highly relativistic or only weakly relativistic, depending upon the mechanism and the objective. Two basic processes are considered: the electron cyclotron maser, and coherent scattering of electromagnetic radiation from relativistic electron beams. The first process exploits the fact that the electron cyclotron frequency is a function of the relativistic factor gamma of an electron beam. The second process (coherent scattering) is primarily an exploitation of the Lorentz transformations which come into play during the interaction of electromagnetic radiation with relativistic particles.