Macroscopic resonances in a planar geometry

Resonance response is a characteristic feature of a system of free particles placed between two oscillating surfaces. The frequencies and widths of the resonances are determined by the mean period of motion of particles in multiple reflections from the walls. Resonances caused by a quasiperiodic macroscopic motion can also arise if the interaction between the quasiparticles related to perturbation of the mean self-consistent field is taken into account. The widths of these resonances are finite and correspond to collisionless Landau damping. The possible connection between the phenomenon considered and nuclear giant resonances is discussed.