Super-radiant multifluxon dynamics in a system of parallel-coupled Josephson junctions

We report experimental observation of steps in the multifluxon I-V characteristics of a long Josephson junction with a lattice of local inhomogeneities. A theoretical model of this effect based on a perturbed sine-Gordon equation is developed. We consider the super-radiant emission of plasma waves in this system and their interaction with a moving fluxon chain. The effect may also be treated as a synchronization of the Fiske oscillation modes in short junctions parallel coupled through the inhomogeneities.