Single vortex dynamics in overdamped Josephson junction arrays

Abstract

We have numerically studied the motion of a single vortex in Josephson Junction Arrays. The vortex velocity (v), the damping coefficient (η) and the dynamical barrier for the cell-to-cell vortex motion (E b ) have been worked out. We show that all these physical quantities depend on the bias current (i dc ) and on the penetration depth of the magnetic field (λ⊥). The velocityv is also studied as a function of the vortex position (x) and extension (r): the vortex accelerates when it is at a distance from the borders of the order of its radius; across the bulk of the array,v is constant. The results obtained can be nicely described in terms of the motion of a particle subjected to a potentialU(x,i dc ,λ⊥,τ), the analytical form of which is discussed.