Excitation of Plasma Waves Propagating Transverse to the Uniform External Magnetic Field

Using the perturbation method, the motion of an electron in a perturbed longitudinal plasma wave is studied. The wavelength of the wave is assumed to be small compared with the electron Larmor radius. The criterion for excitation and damping of the plasma wave is then obtained. Frequencies of waves which are excited are found to be nearly equal to inte-gral multiples of the electron cyclotron frequency. The results is applied to the explanation of the phenomenon of high cyclotron harmonics radiation. As an extension of Landau damping/) we consider damping and excitation of plasma waves propagating perpendicular to the uniform external magnetic field. In a cold plasma, a longitudinal wave propagating transverse to the mag-netic field couples with the transverse wave. Electrons are frozen in a magneti