Macroscopic resonances in plane geometry

The resonance response is a peculiarity of a system of free particles placed between two oscillating surfaces. The widths and frequencies of the resonances are determined by the mean period of motion of the particles multiply scattered off the oscillating surfaces. Including of interaction between quasi particles, which is connected with the mean self-consistent field perturbation, leads to appearance of resonances due to quasiperiodical macroscopic motion. These are finite-width resonances associated with Landau collisionless damping. Possible relation of the phenomenon to giant nuclear resonances is discussed