Wave amplification by two electron beams in the bounded plasma

Electromagnetic waves amplification was investigated in the plasma-two-electron-beam system. The system of two electron beams is the first approach to the theoretical optimal electron distribution function of a beam. The beam characterized by optimal energy distribution function delives the maximal part of its energy to plasma. Contrary to the system with one supercritical beam the system of two beams with propety matched velocities amplifies the waves with markedly smaller initial amplitude. Experimental data show that the efficiency of the energy transfer from beams to the wave reaches 60%. An interesting feature of the wave phase velocity is found. The experimental data are compared with the computer ones