DYNAMICS OF 1-D PARALLEL ARRAYS OF UNDERDAMPED JOSEPHSON-JUNCTIONS

Parallel arrays of underdamped Al - Al2O3 - Al junctions have been fab ricated using a shadow evaporation technique. The critical current is periodic in the applied magnetic field implying that the junctions are uniform. The current-voltage characteristics are hysteretic with seve ral different voltage states observed over a range of bias currents an d applied fields. Voltage plateaus are observed which are reminiscent of Fiske steps in long Josephson junctions however the discrete nature of the arrays does not allow for the standard Fiske step analysis. We have performed linear stability analysis on the equations that descri be the dynamics of the array. The stability analysis shows that period ic solutions to the equations naturally decompose into one center of m ass variable that must be described by a non-linear equation and a set of transverse variables that describe the fluctuations around the cen ter of mass motion. The plateaus in the voltage are related to the nor mal modes of the linearized transverse variables.