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-con sistently contribute to the formation of a stationary stale with self- generated flux. Two types of Josephson vortices are found in this stat e, one with magnetic flux Phi(1)<Phi(0)/2 and another one with magneti c flux Phi(2) = Phi(0) - Phi(1) > Phi(0)/2.