Observation of whispering gallery resonances in annular Josephson junctions

Experiments indicating the excitation of whispering gallery-type electromag netic modes by a vortex moving in an annular Josephson junction are reporte d. At relativistic velocities the Josephson vortex interacts with the modes of the superconducting stripline resonator giving rise to novel resonances on the current-voltage characteristic of the junction. The coupling betwee n the vortex and the linear mo des of the junction is explained using a Che renkov-radiation-like mechanism. We analytically calculate the spectrum of the linear modes taking into account the electromagnetic environment of the junction. The experimental data are in good quantitative agreement with th e analysis and numerical calculations based on the two-dimensional sine-Gor don model. (C) 2000 Elsevier Science B.V. All rights reserved.