Onset and evolution of chaos in a distributed oscillator with delayed feedback (Experiment)

An experimental study was performed on a delayed-feedback microwave TWT oscillator whose active medium consists of a nonequilibrium medium with an electron beam and a traveling electromagnetic wave. Depending on the initial state of the system, different paths of transition to chaos characteristic for simple dynamic systems have been experimentally observed: sequence of period doubling bifurcations, destruction of quasi-periodic motions with three incommensurable frequencies, 'hard' onset of chaos, transition through intermittency, and sequence of torus doubling bifurcations. It is shown that the image of developed stochasticity in the phase space of the system far from the equilibrium state is a gas of strange attractors.