LONG JOSEPHSON-JUNCTIONS WITH UNIFORM DC AND RF DRIVING CURRENTS - GENERAL RESULTS FOR THE PHASE-LOCKED REGIMES

We investigate the dynamics of a long overlap Josephson junction in th e presence of constant and sinusoidally time-varying currents on a fin ite-length spatial interval imposing open circuit boundary conditions at the ends. We scan the behavior of the system in parameter plane reg ions where the phase locking between the fluxon oscillations in the ju nction and the external time-varying field is possible. This scanning is performed for different values of the dc driving term and for lengt hs of the spatial interval ranging from 3.8 up to 15 and dissipation p arameters ranging from 0.025 to 0.25. In spite of the complexity of th e system and of the broad range of parameters investigated we find tha t the response to the rf excitation presents general features that can be well understood in terms of current-voltage characteristics of the junctions (and related experimental parameters). The results are comp ared with a recent theoretical model based on a perturbation approach of the sine-Gordon Hamiltonian.