The 1 MW lower hybrid Frascati F.T. heating-system configuration and first operating experience

The RF additional heating system for the FT Tokamak has been completely assembled and tested at the end of 1981. The system is capable of injecting in the plasma a 1MW, 1 s RF power pulse at 2450 MHz using two 500 kW CW VARIAN klystron amplifiers. The system is designed to achieve the maximum power in two stages; 500 kW initially using a ''two waveguide grill'' coupling structure installed on one port of the machine and 1 MW in the final stage, using 2 coupling structures on two equatorial ports. Preliminary experiments of lower hybrid resonance heating are in progress with the first 500 kW. The configuration of the system and the first operating experience are described. The main results of the testing of the high voltage power supply, the protection systems and the high power microwave components are also presented. (author)