Numerical Investigation of Fluxon Interactions in Josephson Stacks

The existence of stable coherent motions in different physical systems is a problem that attracts much attention in the last years. We study numerically the possibility a coherent (bunched) motion of fluxons allocated at different tunnel barriers of N‐layered (N > 3) long Josephson stacks of linear (open ends) geometry to exist in the absence of external magnetic field. The stability of such configurations is analyzed. It is shown that a system of bunched fluxons reflects from the ends of the junctions without being destroyed. The influence of the number of the stacked junctions on such stable configurations is investigated. The investigation is made in the frame of the Sakai‐Bodin‐Pedersen model of N stacked inductively coupled Josephson junctions. Finite difference methods are used to solve the system of nonlinear hyperbolic (perturbed sine‐Gordon) equations. The accuracy and the conservativity of the method are investigated numerically.