  We demonstrate, experimentally and theoretically, controlled loading of an
exciton-polariton vortex chain into a 1D array of trapping potentials.
Switching between two types of vortex chains, with topological charges of the
same or alternating sign, is realised by means of appropriate shaping of an
incoherent pump beam that drives the system to the regime of bosonic
condensation. In analogy to spin chains, these vortex sequences realise either
a "ferromagnetic" or an "anti-ferromagnetic" order, whereby the role of spin is
played by the orbital angular momentum. The "ferromagnetic" ordering of
vortices is associated with the formation of a persistent chiral current. Our
results pave the way for controlled creation of nontrivial distributions of
orbital angular momentum and topological order in a periodic exciton-polariton
system.
