Frequency increasing and power enhancement of microwave sources based on superradiance from intense electron bunch

Summary form only given as follows. Superradiance (SR) of electron bunches can be considered as effective method of production of ultrashort electromagnetic pulse. Different types of SR associated with different mechanisms (cyclotron, Cherenkov, bremsstrahlung) of stimulated emission were recently observed experimentally at millimeter and centimeter wavelength bands. Progress in these researches has enabled a new type of generator to be created capable of generating unique short (under 200-300 ps) EM pulse at super high peak powers exceeding 1 GW in millimeter and 3 GW in centimeter waveband. In the paper some methods for further increasing of SR pulse peak power alongside with promotion of such sources in high frequency band are presented. For peak power enhancement it is suggested to use the amplification of SR pulse during its propagation along quasi-stationary electron beam. For production of SR pulse in short millimeter and sub millimeter wave band it is attractive to use the stimulated backscattering of powerful pump wave by the relativistic electron bunch. The first experimental observation of such an effect has been reported in Korovin, et al., Phys. Rev. E, vol.74, 016501 (2006).