Plasma assistance diffraction generator

Summary form only given, as follows. Summary form only given. To determinate the possibility of the beam-plasma generators creating in mm range the electrodynamical properties of the structure consisting of a sequence (period D, width d) of metallic rings (radius a) filled with plasma (plasma frequency /spl omega//sub p/) and surrounded by a metallic screen (radius b) has been investigated. The hybrid plasma waves were excited by an electron beam. The dispersion characteristics, fields´ topography, and RF-power flow distribution and their dependence on plasma density has been determined. Dispersion curves were shifted up with plasma density increasing It allows varying the generated frequency. The modes of transit-for-beam canal and coaxial modes were found as volumetric ones contrary to vacuum case with surface modes and low amplification coefficient. So plasma filling can be considered as a tool for generation enhancement. At the same time this system is available for taking off the generated power. For the system geometry a=8.6D//spl pi/, b=23.6D//spl pi/, d=0.1D, and beam current 10A the following values of amplification coefficient, efficiency, total power, and longitudinal electric field were obtained in vacuum (/spl omega//sub p/=0) case 0.1 cm/sup -1/, 2.5 %, 1.6 kW, 0.87 kV/cm and in plasma (/spl omega//sub p/=0.37/spl pi/c/D) case 0.7cm/sup -1/, 14%, 9.4kW, 41kV/cm, correspondingly. The preliminary experiments have been performed and some results will be represented.