FLUXON DYNAMICS IN ONE-DIMENSIONAL JOSEPHSON-JUNCTION ARRAYS

Current-voltage characteristics of an annular array of small Josephson junctions with different values of single-loop inductances are calculated numerically and compared with that for a continuum annular Josephson junction. The resonances between the moving fluxon and the linear waves caused by the array discreteness induce steps on the current-voltage characteristics which do not exist in the continuum case. The voltage position of the steps is found to be in good agreement with the kinematic approach based on the Frenkel-Kontorova model. Our results show that in Josephson devices the discreteness may lead to strong superradiant emission of electromagnetic waves by moving fluxons.