DYNAMICS OF A NONAUTONOMOUS SINE-GORDON SYSTEM MODELING LONG JOSEPHSON-JUNCTIONS

We study the dynamics of an ac and dc driven sine-Gordon system extending over a finite spatial interval. We use this system to model fluxon oscillations in long (one-dimensional) Josephson junctions in the presence of an rf current. For three different values of the normalized spatial interval, or junction length, and a fixed value of the loss parameter the response of the junction is scanned over wide regions of the (rf drive amplitude and frequency) plane. In these regions chaotic intermittency, quasiperiodicity and isochronous phase locking are the most interesting dynamical features. We investigate the range of isochronous phase-locking of the soliton oscillations to the external ac drive in parameter space regions where experimental verification of our data can be considered.