Design concept of 200 kW amplifier at VHF

A 1.5 MW ICRH (ion cyclotron resonance heating) system is being developed to heat the SST-1 (Steady State Superconducting Tokamak-1) plasma during 1000 seconds operation. Different frequencies between 20 MHz to 91.2 MHz have been chosen to allow second harmonic and minority heating at 1.5 T and 3.0 T toroidal magnetic field. Two chains of rf generators would be used to cover the desired frequencies. One is tunable from 20 MHz to 45.6 MHz and the other one is fixed at 91.2 MHz with 2 MHz bandwidth.