Growth and saturation of stimulated beam modulation in a two-stream relativistic klystron amplifier

Summary form only given, as follows. A novel two-stream relativistic klystron amplifier (RKA) is presented in which the amplification of stimulated beam modulation is achieved via the unstable two-stream interaction rather than by the use of passive cavities. After a calculation of the limiting current, the amplification and saturation of the stimulated beam modulation have been analyzed using a cold-fluid model and particle-in-cell simulation. Good agreement is found between theory and simulation in the linear regime. Almost fully modulated intense relativistic electron beams are obtained at saturation.