Effects of diffraction and spatial dispersion on the accuracy of determining energy deposition profiles during ECR plasma heating by quasi-optical microwave beams in large-scale toroidal confinement systems

It is shown that, for the parameters of a toroidal fusion reactor, the ray approximation is quite appropriate for calculating the energy deposition in the region of electron cyclotron resonance, even in the case when the microwave power is launched along the gyroresonant layer. The effect of spatial dispersion on the energy deposition profile is considered, and an expression for the phase modulation of the Gaussian beam during its interaction with the resonant layer is obtained.