Transmission lines for ECRH experiments on FTU tokamak

Recent additional heating experiments of the Frascati Tokamak Upgrade (FTU) ohmic plasmas by electromagnetic (e.m.) waves at 140 GHz Electron Cyclotron Resonance (ECR) frequency confirmed the potential of this heating technique in the study of thermal confinement in fusion devices. The millimeterwave system, so far limited to a peak power of 0.5 MW for 0.1 s, is presently being completed in order to achieve the design performance of 2 MW for 0.5 s. The paper illustrates the main technological features of the ECRH microwave system.