  Using a hydrodynamic model of the free electron gas of metal, we
theoretically investigate optically-induced DC current loops in a plasmonic
nanostructure. Such current loops originate from an optical rectification
process relying on three electromotive forces, one of which arises from an
optical spin-orbit interaction. The resulting static magnetic field is found to
be maximum and dramatically confined at the corners of the plasmonic
nanostructure, which reveals the ability of metallic discontinuities to
concentrate and tailor static magnetic fields on the nanoscale.
