Evolution of the mm-wave Collective Thomson Scattering system of the high-field tokamak FTU

We first describe the improved receiving system of the diagnostic experiment of mm-wave Collective Thomson Scattering being run on the Frascati Tokamak Upgrade (FTU) and then discuss some peculiar problems and new operating procedures related to the investigation of strong anomalous spectra of non thermal origin, many orders-of-magnitude stronger than the ion thermal feature, systematically observed in the experimentation and finally ascribed to a perturbation of the gyrotron that generates the probing beam. Arguments in favor of a possible more general valence of the solutions actuated for the specific case of FTU are finally given.