MANY-FLUXONKINETICS IN AN INHOMOGENEOUS DAMPED dc DRIVEN JOSEPHSON JUNCTION

Radiative effects accompanying a fluxon—antifluxon collision on the background of a localized inhomogeneity (microshortor microresistance) or in a randomly inhomogeneous long Josephson junction arestudied. The total emitted energy andthe corresponding threshold value of the bias current density for radiative annihilation of a fluxon—antifluxon pair into a breather are found. Theobtainedresults areapplied to aqualitative description of neutral fluxon—antifluxon “rarefied gas” in ajunction with periodic or random inhomogeneities. In particular, we obtain an estimate for the maximum possible equilibrium density of the “gas” atgiven density ofbias current. Some kinetic characteristics ofthe “gas” in anon-equilibrium state, e.g. mean lifetimeand free path length of a fluxon in the case when thedensity exceeds the equilibrium value, areestimated too.