An analysis of the cut-off and resonance positions for the helical axis 'heliac' device TJ-II has been performed stressing the peculiarities of the injection of electron cyclotron waves into this unusual magnetic configuration. The optimum ways of injection were determined as well as the effects of plasma density on wave propagation and the density limit for waves at the 2nd harmonic in the X-mode and at the fundamental frequency in the O-mode.
Electron cyclotron heating scenario and experimental results in LHD