QUASI-OPTICAL CALCULATIONS OF ECRH POWER DEPOSITION

A quasi-optical description of wave beam propagation is described and applied to the calculation of the ECRH power deposition profile in typical tokamak experiments. The quasi-optical model allows a proper description of the effects on beam propagation and absorption from finite spatial and spectral width of the beam as well as from finite spatial and spectral inhomogeneity. Typically, quasi-optical effects result in broadening of the power deposition profile. In case of the ITER Upper Port ECRH launcher this results in up to a factor of two reduction of the figure of merit for NTM or sawtooth control as compared to previous estimates.