Solid-State Klystron Driver for Lower Hybrid Current Drive (Phase I)

Launching radio frequency (RF) waves from the high-field side (HFS) of a tokamak has the potential to be an efficient off-axis current drive method while reducing the plasma-material interaction issues of the antenna. Researchers at the Plasma Science and Fusion Center (PSFC) at the Massachusetts Institute of Technology (MIT) have proposed to reuse existing equipment at MIT, including CPI klystrons, to demonstrate HFS RF launching at DIII-D. Eagle Harbor Technologies (EHT), Inc. is developing the next-generation klystron driver for use by MIT for HFS RF launching experiments at DIII-D. The next-generation klystron driver will take advantage of the high frequency solid-state switching capabilities developed by EHT with support of the DOE SBIR program. The high frequency nature will allow for the development of a more compact system, which can be placed closer to the klystrons. This system will be designed so that there is one driver per klystron, which will allow the system to scale as more klystrons are added and experiments to continue in the event of a klystron fault. We will present the Phase I project plan and overview of progress to date.