Interaction of rf field with a half-infinite Josephson junction

A standard sine-Gordon model of a half-infinite damped driven Josephson junction is considered, the external drive being accounted for by a boundary condition. For the case of a low-frequency ac drive we study oscillations of a fluxon pinned by the junction's edge and obtained an estimate for a range of values of the pinning energy where the driven oscillations are chaotic, which eventually implies chaotic depinning of the fluxon. For the case of the ac drive with a near-resonant frequency (i.e. close to the junction's plasma frequency) we find the wavenumber and amplitude of the driven plasma wave and the corresponding rate of energy absorption by the junction. The dependence of these quantities on the resonance frequency detuning proves to be hysteric. Finally, we consider the case when the external drive contains, on a level with near-resonant ac component, a dc one. We demonstrate that, the dc component being sufficiently large, the hysteresis disappears.