Unusual radiating Josephson vortex

Traveling vortices in a Josephson junction embedded in a decelerating media are studied. It is shown that in such a system, in addition to the usual Josephson vortices whose velocity is limited by the Swihart velocity, there can exist unusual vortices having a large limiting velocity. The conditions for the parameters of the Josephson transition and the external medium where these vortices can radiate electromagnetic waves into the medium due to the Vavilov–Cherenkov effect have been established. The characteristic frequencies of these waves fall in the terahertz region and are smoothly tunable, which is interesting for the use of unusual vortices in the design of compact superconductor devices.