It was shown that the assumption of straight-line probing beams, which is usually used in reconstructing the plasma density profile from interferometric measurements, leads to unacceptably large errors in the case of a dense plasma. A fast method based on the assumptions of geometric optics is proposed for calculating the interferometric signal. This method takes into account the refraction of the probe wave and can be used in reconstruction of the plasma density profile. The method correctness is confirmed by comparison with the results of full-wave calculations.

The possibility of local measurements of the level of the radial plasma velocity fluctuations by the equatorial enhanced scattering of a narrow microwave beam in the upper hybrid resonance in the core plasma of a tokamak is demonstrated. The limitations of the proposed method are clarified at the periphery of the plasma, where the amplitude of density fluctuations grows and small-angle scattering of microwaves on them along the path to the upper hybrid resonance and back becomes significant.