Introduction Turbulent transport plays a key role in plasma confinement which makes understanding and control of plasma turbulence one of the major goals of fusion research. The tools for turbulence characterization include radial correlation reflectometry, which probes the coherency between two cutoff layers using two microwaves at different frequencies incident normally onto magnetic surface. By performing correlation analysis of reflected signals, the information about turbulence properties, such as radial correlation length can be extracted. However, due to dominant contribution of small-angle scattering off long-scale fluctuations in the reflected signal, the radial correlation length is overestimated at small turbulence levels [1,2]. One of the methods to counteract this effect is so-called radial correlation Doppler reflectometry (RCDR) or backscattering (BS) technique, which utilizes probing beam at oblique enough incidence to suppress small-angle scattering contribution to the BS signal. This approach was justified in analytical theory [3] and applied in FT-2 tokamak experiment, where the first comparison of the RCDR data to the results of the global gyrokinetic (GK) modeling with ELMFIRE code was performed [4].
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