Fluxon propagation and Fiske steps in long Josephson tunnel junctions

The dynamical behavior of fluxons propagating in the presence of an applied magnetic field on an overlap-geometry Josephson tunnel junction of length 5λJ having a McCumber βc=5π is studied by numerical integration of the circuit equations of a 50-section lumped RSJ-type (resistive shunted junction) model.

Resonant propagating configurations corresponding to the first and third Fiske steps are found. The fundamental frequencies and power levels of the radiation emitted from one end when the junction is biased on the first and third Fiske steps and on the first zero-field step are comparable, but a magnetic field renders the power spectra at the two ends of the junction different.