Self-generated flux in Josephson junctions with alternating critical current density

We study an interesting state with a self-generated magnetic flux in a long Josephson junction. The critical current density j c is assumed to alternate randomly along the tunnel contact on a length scale much less than the local Josephson penetration depth. The phase difference is then a sum of an alternating term and a smooth term which self-consistently contribute to the formation of a stationary state with self-generated flux. Two types of Josephson vortices are found in this state, one with magnetic flux F1,F0/2 and another one with magnetic flux F25F02F1.F0/2. @S0163-1829~98!50306-2#