FLUXON DENSITY WAVES IN LONG JOSEPHSON-JUNCTIONS

Numerical simulations of the multiple fluxon dynamics stimulated by an external oscillating force applied at a boundary of a long Josephson junction are presented. The calculated I-V characteristics agree well with a recent experimental observation of rf-induced satellite flux-fl ow steps. The voltage spacing between the satellites and the main flux -flow step corresponds to the second harmonic of the external frequenc y. We find that the satellite flux-flow modes are characterized by col lective excitations propagating through the fluxon chain. These dynami cal states can be interpreted as fluxon density waves.