Nonlinear features of two-plasmon decay in a long-scale-length plasma

A transparent model of two-plasmon decay in a spatially homogeneous or long-scale-length plasma, reproducing the main experimentally observed nonlinear features, is presented. Secondary coupling between the plasma waves and the ion-acoustic waves, including their frequency mismatch, proves to be the principal saturation mechanism of the instability. The wave amplitude time evolution and spectra as well as the hot-electron generation properties are compared to the experimental data.