MW-scale ICRF plasma heating using IGBT switches in a multi-pulse scheme

Solid-state silicon switches are cheap and reliable option for 1–10 MHz RF power sources, required for plasma ion cyclotron RF heating (ICRF). The large 'on' resistance of MOSFET and similar devices limits their power delivery to a few tens of kW per switch. Low resistivity devices, such as IGBT, suffer from large 'off' switching time, which limits their useful frequency range and increases the power dissipated in the switch. Here we demonstrate more than 0.8 MW circulated RF power at 2 MHz using only three high voltage IGBT switches. The circuit uses the fast 'on' switching capability of the IGBTs to generate high-Q pulse train. This operation mode also simplifies the measurement of RF coupling between the antenna and the plasma