Whistler Waves Emitted by a Thin Modulated Electron Beam

The theory of whistler wave interaction with a modulated electron beam of finite radius, injected parallel to the magnetic field in an unbounded space plasma is considered The study is done in the case of sheared whistlers interacting with the thin beam, when the parallel wave number is very small compared to the perpendicular one. The electromagnetic fields inside and outside the beam are determined in the linear approach; their asymptotic expressions in the beam vicinity are obtained in a rather simple form. The energy balance between the thin modulated beam and the sheared whistler is considered and dependence of emission power on the beam parameters is studied.