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An upgraded version of a quasi-optical diplexer combiner, based on a resonating system coupling two transmission lines using three Dielectric Beam Splitters, has been realized and tested. This device is principally thought to combine power coming from different transmission lines into a single output or to switch the injected power between different outputs, but it could also be used as mode filter or in line viewing system for Electron Cyclotron Emission (ECE) or Collective Thomson Scattering (CTS) diagnostics. The design was implemented in order to link two transmission lines of the ECRH system on FTU, for power combination of two beams into a single line of the new ECRH launcher recently installed. This device is based on Dielectric Beam Splitters (DBS); it has been tested at low power in order to confirm the splitting ratio foreseen from simulation and its efficiency has been evaluated measuring the beam exiting the system. The design and the characterization of the diplexer combiner are reported in this paper.

The Electron Cyclotron (EC) fast launcher for real time control experiments has been installed on FTU and characterized to be fully integrated in a real-time MHD control module under development. The launcher scheme is based on a two module system, symmetric with respect to the equatorial plane of FTU, with a front steering concept and the launched beams are real-time controllable both in poloidal and toroidal directions. Specific design parameters, defined by the FTU MHD dynamics (typically island size and q profile changes), are the beam dimensions with zooming capabilities, the steering range and mirror speed with the most demanding requirement on poloidal speed of the Steering Mirror (SM) Δθ = 1° in 10 ms. A set of tests has been done to verify the system performance. High power tests of the launcher have been done on a 500 kA, 0.5·1020m−3 and 5.3 T plasma with 2·300 kW of EC power delivered to the plasma. The steering mechanism was tested under the automatic control system and showed a dynamic response in line with the requirements. Results of these tests will be presented in the paper.

We first describe the improved receiving system of the diagnostic experiment of millimeter-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 nonthermal origin, many-orders-of-magnitude stronger than the ion thermal feature merged in them, systematically observed in the experimentation, and finally ascribed to a perturbation of the gyrotron that generates the probing beam. Arguments in favor of a more general valence of the solutions actuated for the specific case of FTU are finally given. [ABSTRACT FROM AUTHOR]

Discusses the use of arrays of thermophile detectors arranged on flat panels to measure stray radiation from high-power transmission lines in a FTU tokamak electron cyclotron resonance heating experiment. Instruments' insensitivity to polarization and to the direction of propagation; Requirement of amplification and synchronous detection.