Cherenkov Radiation of Vortices in a Two-Dimensional Annular Josephson Junction

Abstract

A two-dimensional annular Josephson junction is considered in the framework of the $(2+1)\mathrm{D}$ sine-Gordon equation. By numerical simulations it has been found that once vortex velocity exceeds the critical value a resonance excitation of linear traveling waves appears. The critical velocity of vortices and the radiation field structure are determined. The current-voltage characteristic of such a junction is presented. It has been shown analytically that this effect is brought about by the Cherenkov synchronism between linear waves of the whispering mode type and moving vortices. All analytical results obtained in this study are in good agreement with the numerical experiment data. In conclusion, a possibility of using the discovered effect for generation of microwave radiation is discussed.