Nonlinear interaction between ordinary electromagnetic modes

Abstract

Resonant interaction between three ordinary modes, modified by electrons streaming parallel or antiparallel to the static magnetic field of a homogeneous plasma, is investigated. The modes propagate perpendicular to the magnetic field. If the unperturbed current density is zero, the scattering matrix for three-wave resonant interaction depends only on the cube of the electron drift velocity. If two electron beams of equal density are counter-streaming, the scattering matrix vanishes completely. If the unperturbed current density is non-zero, the matrix depends on the linear and cubic terms in the electron drift velocity. In the present investigation, the Hamiltonian approach, which is microscopic in nature, has been used, and therefore the results are valid for arbitrary ratios of Larmor radius to wavelength.