Chaotic operation of a delayed-feedback klystron oscillator: Theory and experiment

The dynamics of a delayed-feedback microwave self-excited oscillator built around a drift-tube klystron is studied theoretically and experimentally. It is revealed by computer simulation that the operation of this oscillator must be undergoing an intricate sequence of bifurcations, with the bifurcation parameter being proportional to the beam current and the amount of feedback. The oscillator thus alternates between regular and chaotic modes of self-modulation. The transitions to chaos mostly proceed via a succession of period-doubling bifurcations. The operation of an experimental oscillator with a five-cavity amplifier klystron is tested. The experimental results agree with the simulation data in qualitative terms.