Cyclic beam bunchers and wave generators

An electromagnetic wave circulating in a toroidal or cylindrical cavity in a TE mode with a superimposed magnetostatic betatron field is capable of producing deep density modulations on an intense relativistic electron beam or of amplifying the electromagnetic wave when the phase velocity of the wave is matched to the beam cyclotron frequency. Examples of operation of cyclic devices in both the beam bunching mode and wave amplifying mode are presented.