Unified formalism of lower hybrid parametric instabilities in plasmas

Abstract

A unified theory of parametric instabilities in the lower hybrid frequency region is formulated using the drift kinetic equation for electrons and the Vlasov equation for unmagnetized ions. The three wave decay process into various decay channels (viz., two lower hybrid waves, lower hybrid and ion acoustic waves) are examined and compared for various pump frequencies and powers. Nonlinear scattering rates by electrons and ions (i.e., nonlinear Landau damping) are evaluated and compared with previous calculations. It is seen that the dominant channel of decay is through ion acoustic and lower hybrid waves when Te/2Ti≳4 and through lower hybrid waves and lower hybrid quasi-modes when Te/2Ti<4.