Fiske modes and Eck steps in long Josephson junctions: Theory and experiments

We report on a systematic investigation of the properties of long Josephson junctions under the application of magnetic fields generating Fiske and Eck steps in the current-voltage characteristics. Numerical data and experimental results are compared with a cavity mode-based model predicting the voltage position and the amplitude of the current singularities. The comparison shows that this model can account for the shape and for the maximum current modulation of the singularities when the field penetration overcomes Meissner shielding above the value $H_0=2\mathrm{}{\lambda }_j{j}_c.$