CHERENKOV RADIATION IN COUPLED LONG JOSEPHSON-JUNCTIONS

Evidence for Cherenkov radiation of a Josephson vortex is observed in the system of two magnetically coupled long Josephson junctions. This radiation leads to resonances which appear above the lowest characteri stic velocity (c) over bar of the linear electromagnetic waves. Resona nces result from interaction of a Cherenkov wave with a moving Josephs on vortex and, in annular junctions, occur when the vortex makes one t urn around the junction. Experimental data are in good agreement with the proposed model and simulations which provide a clear physical pict ure of the observed effect.