Nonlinear amplification of powerful terahertz pulses by electron bunches

There is a concept of the amplifier based on a principally non-linear effect of reflection of an electron bunch from the powerful wave pulse. This is effective mechanism of energy extraction by the wave from particles, when parameters of the electron bunch (initial energy spread, bunch length and emittance) haven’t significant influence on the efficiency of the electron-wave interaction. Two schemes of possible realization of this process (non-resonant and resonant electron-wave interaction) are described.