Nonlinear wave interactions in two-electron-temperature plasmas

Abstract

The evolution of nonlinear electron plasma waves is considered for cases where the electron distributions are characterized by more than one temperature component. The standard models for the decay spectrum of electron plasma waves are significantly modified in such cases, since the presence of electron acoustic modes in multi-temperature plasmas opens a new decay channel for the high frequency plasma waves. In particular, long wavelength Langmuir waves can decay to shorter wavelengths. A set of equations are derived for describing weakly nonlinear waves in two-electron temperature plasmas. The results are illustrated by numerical solutions of the basic equations in two spatial dimensions. The analysis is extended to cases characterized by many temperatures, and a possibility of including Landaudamping in a simple time-reversible form is discussed.