Resonant mixing in the dynamic state of long Josephson junctions

Spectrum of oscillations in the dynamic state of long Josephson junction (J J) in parallel magnetic field is studied analytically and numerically. In t he Aux-flow state, interaction of the moving fluxon train with the edges of the JJ results in resonant generation of an acoustic fluxon density wave. A new type of resonance occurs at higher voltages, above the Aux-flow branc h. Here the spectrum consists of two correlated frequencies. Resonant mixin g with the fundamental Josephson frequency results in large amplitude of os cillations. Possible applications of such resonant mixing as a frequency mu ltiplier and adjustable narrow line-width generator are discussed. (C) 2000 Elsevier Science B.V. All lights reserved.