  A new class of artificial atoms, such as synthetic nanocrystals or vortices
in superconductors, naturally self-assemble into ordered arrays. This property
makes them applicable to the design of novel solids, and devices whose
properties often depend on the response of such assemblies to the action of
external forces. Here we study the transport properties of a vortex array in
the Corbino disk geometry by numerical simulations. In response to an injected
current in the superconductor, the global resistance associated to vortex
motion exhibits sharp jumps at two threshold current values. The first
corresponds to a tearing transition from rigid rotation to plastic flow, due to
the reiterative nucleation around the disk center of neutral dislocation pairs
that unbind and glide across the entire disk. After the second jump, we observe
a smoother plastic phase proceeding from the coherent glide of a larger number
of dislocations arranged into radial grain boundaries.
