Generation, amplification, and nonlinear self-compression of powerful superradiance pulses

Superradiance (SR) of electron bunches can be considered an effective method of production of ultrashort electromagnetic pulses. Different types of SR associated with different mechanisms (cyclotron, Cherenkov, and bremsstrahlung) of stimulated emission are observed experimentally in the millimeter and centimeter wavelength bands. Progress in this research has enabled a new type of generator to be created capable of generating unique short (under 200-300 ps) electromagnetic pulses at super high peak powers exceeding 1 GW in the millimeter and 3 GW in the centimeter waveband. Some new methods for further increasing of the SR pulse peak power along with the promotion of such sources to higher frequency bands are discussed. These new methods include phase synchronization of several SR pulse generators, the amplification of an SR pulse during its propagation along a quasi-stationary electron beam and nonlinear compression in the process of induced self-transparency.