RF driven long Josephson junctions

An analysis of the behavior of zero-field resonances in long Josephson tunnel junctions under the influence of RF fields is performed. The measurements lead to establish some criteria under which fluxon oscillations are stable. The stability is investigated mainly via the relation between the amplitude of the current singularities and an external magnetic field. We find that the junction is able to support the fluxon´s steady motion almost as long as the amplitude of the RF signal does not disrupt the d.c. Josephson current.