Experimental validation of the intensity refractometry principle for density measurements at the edge of a tokamak

Experimental validation is presented for a new type of microwave diagnostic, first introduced in the theoretical study M. Usoltceva et al., Rev. Sci. Instrum. 93, 013502 (2022). A term adopted this technique to highlight its difference from interferometry: intensity refractometry. The diagnostic allows measuring electron density, and work, it applied at edge tokamak. implementation ASDEX Upgrade, called Microwave Intensity refractometer Limiter Shadow (MILS), provides experimental proof concept. Densities predicted by MILS are compared several other diagnostics. agreement discrepancy various radial regions density profile analyzed possible reasons discussed. wide coverage shown example discharges with densities 2*10^17 m^-3 2*10^19 limiter position. In these experiments, location measurements varied 5 cm front (up 1 inside separatrix was measured) 3 shadow. challenges operation data processing presented.