пространственный заряд.

In the article two­dimensional model of interaction between infinitely thin electron beam in longitudinal magnetic field and traveling electromagnetic wave has been considered; in the frames of two­dimensional linear theory integral equation described such interaction has been formulated. On the basis of derived dispersion relation condition of initiation of beam instability has been found and influence of space charge fields on the processes of interaction has been analyzed.

The theory of waveguide excitation is presented, based on expansions of the electromagnetic field by proper waves of waveguide. Necessary properties of smooth and periodic waveguides, including the conditions of orthogonality of plane and the volume of the waveguide are given. Main properties of pseudo-periodic waveguides are described. Thisis a new class of waveguide systems. Different forms of the waveguides-excitation theory are considered.