| Abstract: | The parametric excitation of longitudinal waves in an infinite homogeneous plasma by a pump field E (t) = E 0(t) sin (ω0t + φ(t)) is studied on the basis of the Vlasov equation, where the amplitude E 0(t) and the phase φ(t) are slowly varying compared with ω0 periodic functions. Firstly it is assumed that ω0 is much larger than the electron plasma frequency ωLe. In the second part the parametric instabilities are considered under the resonance condition ω0 ≈ ωLe. In both parts the threshold fields for the excitation of the longitudinal waves and their growth rates are calculated. As an example these values are analysed for both a sequence of pump impulses and a phase-moduated pump field. They are compared with the results received for a monochromatic pump field. |
