We study plasma oscillations in a bounded two-dimensional electron fluid. The use of a variational method allows a simple analysis of plasma modes in a strip of finite width. For the exactly solvable model that neglects the pressure gradient in a plasma confined to a semi-infinite plane a simple one-parameter variational function gives the edge plasmon frequency reasonably close to the exact value. In the case of the semi-infinite plane we also incorporate the effects of the pressure gradient in our variational solution. In a two-dimensional strip of finite width we find the symmetric and antisymmetric plasma modes of different frequencies. The method used here can be readily extended to include the effects of applied magnetic fields and different confinement geometries.

• Received 11 July 1996

DOI:https://doi.org/10.1103/PhysRevB.55.4684