Collision of a free fluxon in a long dc-driven damped Josephson junction with a fluxon pinned by the microshort or microresistor is analyzed by means of perturbation theory. It is demonstrated that, in the case of like polarities of the fluxons, three different outcomes of the collision are possible: depinning, capture, and exchange. If the polarities are opposite, the possible outcomes are depinning, annihilation, and a quasielastic collision. The boundaries between the different regimes in the parametric space of the model are found.
Physical Review B, 1992, Vol 45, Issue 21, p. 12435-12441