Plasmonic shock waves and solitons in a nanoring

We apply the hydrodynamic theory of electron liquid to demonstrate that a circularly polarized radiation induces the diamagnetic, helicity-sensitive dc current in a ballistic nanoring. This current is dramatically enhanced in the vicinity of plasmonic resonances. The resulting magnetic moment of the nanoring represents a giant increase of the inverse Faraday effect. With increasing radiation intensity, linear plasmonic excitations evolve into the strongly non-linear plasma shock waves. These excitations produce a series of the well resolved peaks at the THz frequencies. We demonstrate that the plasmonic wave dispersion transforms the shock waves into solitons. The predicted effects should enable multiple applications in a wide frequency range (from the microwave to terahertz band) using optically controlled ultra low loss electric, photonic and magnetic devices.