Absorption of Microwaves During Plasma Heating at the Second Harmonic of Electron Cyclotron Resonance in Tokamaks and Stellarators: Linear Theory and Experiment

We study the microwave absorption during electron cyclotron resonance heating (ECRH) by extraordinary wave at second harmonic (X2 mode) in T-10 tokamak and TJ-II stellarator a wide range of plasma densities, compare experiments with classical formulas for injected ECR power. Empirical relations efficiency critical density n cr , which separates regions full partial power, are obtained using numerical simulation heat transport model canonical profiles. It is shown that both devices, densities exists, where predicted almost full, while according empirical formula, only small fraction power absorbed. The allow ones to optimize conditions ECRH toroidal systems magnetic confinement.