Dot and antidot edge magnetoplasmons for a two-dimensional electron gas in a ring geometry

The dynamical response of a classical two-dimensional electron gas confined in a ring geometry under a perpendicular magnetic field is analyzed. Within the hydrodynamical approach and in the strong magnetic-field limit, a new set of antidot edge magnetoplasmons is obtained, corresponding to density oscillations circulating along the inner boundary of the ring and whose frequency increases with magnetic field. The associated self-induced distribution of densities and currents are presented, together with an analysis of the size dependence of these perimeter waves.