Absolute parametric decay instabilities in ECRH experiments and their possible role in the missing power effect at the T-10 tokamak

The possibility of excitation of absolute parametric decay instabilities in X2- and O1-mode electron cyclotron resonance heating experiments with monotonic density profile and their possible consequences for the EC absorption efficiency under conditions of the T-10 tokamak are considered. Theoretical predictions are used to explain the puzzling results of the energy balance analysis in T-10.