Coherent amplification of volume plasmons

It is shown that volume plasmons can be coherently amplified by a high-intensity electron beam. Because of natural damping of the plasmons and scattering of the electrons by ions in the metal the required electron-beam intensity is of the order of 1013 A/m2. Although the plasmons are confined inside the metal, they can be detected by their effect on the energy of the electrons emerging from the metal and by the enhancement of the transition radiation at the plasma frequency