Fluxon propagation, zero-field steps, and microwave radiation in very long Josephson tunnel junctions

Abstract

Resonant propagation of two fluxons on an overlap-geometry Josephson tunnel junction of length 10l, having a McCumber bc = 5r is studied by numerical integration of the circuit equations of a 100-section lumped resistive shunted junction type (RSJ) model. Two different modes of propagation are observed: a symmetric fluxon-antifluxon mode and an asymmetric fluxon-fluxon mode. Which mode is stable depends on the value of the bias current. The existence of these two modes gives rise to a fine structure in the second zero-field step in the dc current-voltage characteristic of the junctions and to very different power spectra of the associated radiation emitted from the junction.