Parametric Excitation of Coupled Waves. II. Parametric Plasmon-Photon Interaction

TLDR

The paper extends the general theory of parametric excitation of coupled waves to the interaction between electrostatic plasma waves and near‑electron‑plasma‑frequency radiation. Using hydrodynamic equations, the authors derive coupled equations for electron plasma and ion acoustic waves, incorporate Landau damping phenomenologically, and obtain analytic expressions for threshold intensity, threshold frequency shift, and above‑threshold growth rate, analyzing their wavelength dependence. The theoretical predictions are validated against the experimental data of Stern and Tzoar.

Abstract

The general theory of the parametric excitation of coupled waves developed in the preceding paper is applied to the parametric interaction of the electrostatic waves in a plasma with radiation whose frequency is close to the electron plasma frequency. On the basis of the hydrodynamic equations, the coupled equations for the electron plasma wave and ion acoustic wave are derived. The effect of the Landau damping is also considered phenomenologically. Using the coupled wave equations, the expressions for the threshold radiation intensity, the frequency shift at the threshold and the growth rate above threshold are obtained. In particular, the dependence of these quantities on the wave-length of the electrostatic waves is discussed in detail. The results are compared with experiment of Stern and Tzoar.