“Supersoliton” excitations in inhomogeneous Josephson junctions

Multi-fluxon I-V characteristics of an annular Josephson junction with a periodic lattice of inhomogeneities have been simulated numerically in the framework of the perturbed sine-Gordon model. When the space periods of a fluxon chain and the lattice of inhomogeneities are incommensurable, resonance branches appear in I-V characteristics. These branches are supposed to be due to a new type of nonlinear excitations in Josephson junctions, which may be interpreted as solitons of the fluxon density.