Microwave-induced "Devil's Staircase" structure and "chaotic" behavior in current-fed Josephson junctions

We have obtained the various types of I-V characteristics measured experimentally and in analog simulations, by merely changing the junction and the microwave parameters within the same resistively shunted junction model with purely sinusoidal current-phase relation. It was found that the subharmonic steps do exist in the limit βc→0, though they can have finite rounding without thermal noise. The statistical properties of the "chaotic" solutions wer e discussed and their effective temperature was defined and calculated.