• N.S. Ginzburg, V.I. Belousov, G.G. Denisov, R.M. Rozental, A. Sergeev, I.V. Zotova
  IAP/RAS, Nizhny Novgorod
• A.G. Reutova, K.A. Sharypov, V.G. Shpak, S.A. Shunailov, M.R. Ulmaskulov, M.I. Yalandin
  RAS/IEP, Ekaterinburg

Funding: This work was supported by the RFBR grant no.05-02-17553

Recently significant progress was archived in the generation of multimegawatt subnanosecond pulses in millimeter wave band utilizing the cyclotron and Cherenkov mechanisms of superradiance (SR) [1,2]. We study the novel mechanism of SR when the powerful pumping wave undergoes the stimulated back scattering on the intense electron bunch. Due to the Doppler up shift the radiation frequency can significantly exceed the frequency of the pumping wave. With the relativistic microwave generator as a pumping wave source such a mechanism can be used for generation of the powerful pulse radiation in the short millimeter and submillimeter wave bands. Experiments on the observation of the stimulated scattering in the superradiance regime were carried out at Institute of Electrophysics RAS with two synchronized accelerators. The 4 ns electron beam from the first accelerator is used for generation of the 38 GHz 100 MW pumping wave which subsequently scattered on the subnanosecond 250 keV 1 kA electron bunch produced by the second accelerator. The SR pulses with duration 200 ps and peak power about 1 MW were generated. The spectrum of scattered signal included the frequencies up to 150 GHz.

[1] Ginzburg N., et al. Phys.Rev.Lett.,1997, 78 (1997) 2365. [2] Ginzburg N., et al. Phys.Rev. E, 1999 60 3297.