9402020 Orlando Technical abstract: The diffusive and ballistic motion of vortices in one and two dimensional arrays of Josephson junctions will be studied both experimentally and numerically. By using niobium arrays we will explore a new physical regime where the penetration depth is smaller than the unit cell of the array. These investigations will be used to model vortex motion, to study coherent motion of vortices, and to study novel phase-locked solutions of non-linear dynamical systems. With sub-micron size junctions, the arrays can exhibit ballistic motion of the vortices and give rise to mesoscopic transport which. Non-technical abstract: Josephson junctions form the basis of most devices in superconducting electronics. We will study a lattice of such devices coupled together. In such a lattice the magnetic field is bound in bundles of quantized magnetic flux called vortices. These arrays allow one to study vortex motion in new regimes where motion can be ballistic and can give rise to novel collective states that are coherent or even quantum mechanical. By understanding such motion one will be able to design more efficient and novel superconducting electronic devices. One can also add to the understanding of quantum mechanical effects which occur on macroscopic (rather than atomic) lengths and to the understanding of new non-linear effects in dynamical systems. ***