New 30 MHz TFTR high power ICRF sources

The TFTR ICRF system consists of six multimegawatt RF sources providing radio frequency power to antennas located at four bays on TFTR. Power levels of more than two megawatts have been supplied by each of there sources at pulse width of three seconds. Two of the sources were designed and built by the Princeton Plasma Physics Laboratory's (PPPL) RF engineering group and currently operate at 30 MHz; the other four sources are modified versions of the 80 MHz transmitters originally built for the Fusion Material Irradiation Test Facility by Continental Electronics Manufacturing Company. Prior to fiscal year 1997 (FY97) the modified FMIT sources operated over the 40-to-80 MHz frequency range. At the end of FY96 two of PPPL's 40-80 MHz FMIT sources were loaned to Massachusetts Institute of Technology (MIT) to support the C-MOD experimental program. PPPL replaced these sources with two new 30 MHz sources. These units were assembled both from new cavity components designed by PPPL and from components of some of the original 80 MHz FMIT's stored at Princeton. The new 30 MHz FMIT sources were commissioned and operational on TFTR in February 1997. This paper describes the detailed design and analysis of the intermediate power amplifier and driver stages of these new sources and their subsequent fabrication and commissioning.