Parametric excitation in inhomogeneous solid state plasma

The parametric excitation in inhomogeneous one component solid state plasma consisting only of electrons and subjected to the space independent periodic electric field is established. The parametric excitation of the density waves in semi-conductor plasma by electromagnetic radiation was predicted recently by Tzoar1. He considered the non-linear mechanism that enhances the plasma density fluctuations and makes the ion-acustic waves possible in semi-conductor plasma. If there exist the density gradients in the plasma, the electrons may interact with themselves indicating that the parameteric excitation is possible in electron plasma.