Reordering of the structure of intrinsic modes with their parametric excitation in a plasma-beam waveguide

The work is dedicated to a nonlinear theory of parametric beam-plasma instabilities with consideration of distortion of the transvers structure and polarization of the waveguide modes. Analytical solutions are acquired of nonlinear equations which are written with a precision to cubic members. The role of reordering of a waveguide mode structure at the instability saturation stage is evaluated.