Theoretical aspects of the electronical devices operating due to interaction between annular electron beams and the azimuthal surface waves

The physical basis is discussed of electronic devices whose operation is based on the beam or dissipative instability of the azimuthal surface waves (ASW). The ASW are electromagnetic surface waves with extraordinary polarization (with field components Er, Eφ, Hz), propagating across the axial external steady magnetic field in the cylindrical metal waveguide with cold plasma filling. The ASW fields are described by Maxwell equations. To solve the problem, the authors used the Fourier method and numerical simulation of the equations obtained. The ASW excitation was examined under conditions of beam and dissipative instabilities due to the electron beam motion. The correction to ASW eigenfrequencies caused by the waveguide chamber noncircularity was also studied. ASW delaying leads to a negative frequency correction. The ASW energy can be emitted from the narrow slot in the metallic chamber of the waveguide. The optimum wavenumber range was found where the increment values are much greater than those of the ASW decrement caused by their energy radiation. (author). 2 figs., 3 refs