Multi-megawatt solid state RF source

Summary form only given. An RF system using solid state switching has been designed and constructed that is capable of driving a loop antenna with a circulating power of 60 megawatts for millisecond pulses. The primary application of this system is to produce an oscillating magnetic field in the frequency range of 0.2 to 0.7 MHz, to generate and sustain a large plasma current. The maximum power transfer from the RF source was measured to be greater than 10 megawatts. The driver consisted of 12 insulated gate bipolar transistor (IGBT) modules driven in parallel, and was capable of switching 20 kA at 1700V. A sinusoidal current waveform with large circulating currents was obtained on the antenna by incorporating the antenna in a high Q (60), parallel LCR resonant circuit. The low impedance switch driver was matched to the antenna load through a 20:1 step-up, air core transformer with a coupling efficiency of 99%. In order to go through higher power, a somewhat different approach will need to be employed. The design of a much larger (/spl sim/1 GW circulating power) will be presented.