Collective effects associated with lower hybrid heating of plasma

Nonlinear processes associated with plasma heating using radiofrequencies near the lower hybrid frequency are considered. In this frequency range, parametric instabilities are easily excited and the resulting plasma turbulence leads to increased absorption of RF power. Study of the spectrum of this turbulence enables the absorbed energy distribution over the plasma cross-section to be evaluated. It is shown that collective effects are mainly responsible for the absorption of RF power.