High Performance Electronics for Millimeter-Wave-to-Terahertz Plasma Diagnostics Instrumentation and High Power Devices

Fusion energy has great potential to meet the ever increasing global energy demand. The most promising magnetic confinement device, the tokamak, remains the dominant candidate for fusion power generation. The generated thermal power from tokamaks is comparable to fission nuclear power, but with no possibility of catastrophic accidents (such as the melting of fuel rods in the Fukushima I reactors caused by the failure of the cooling systems) if the facilities were damaged. This safety feature arises from the fact that magnetic fusion can only be achieved under very precise circumstances, and damage to any key system will immediately result in a cessation of the fusion reaction. Our goal is to develop advanced visualization tools via imaging diagnostics to provide fundamental physics understanding and thus help determine the optimum path to achieve and sustain magnetic fusion. High resolution Terahertz (THz) imaging diagnostics are exceptionally well suited to this task due to the characteristic properties of fusion plasmas at THz frequencies.;High performance electronics have been developed for the far-infrared tangential interferometer and polarimeter (FIReTIP) system on the National Spherical Tokamak Experiment (NSTX) device. This work significantly increased both the phase and temporal resolution of the FIReTIP system, thereby allowing it to monitor high frequency density and magnetic field fluctuations up to 4 MHz with unprecedented accuracy, which is of critical performance as characterizing these fluctuations are essential in understanding transport physics issues in fusion plasmas.;The millimeter-wave and THz spectral region offers tremendous potential for a diverse range of applications outside of plasma diagnostics in fields such as communications, biomedical diagnostics, remote imaging and concealed weapons detection. The unique THz spectral region offers exciting and novel application opportunities arising from its inherent advantages in spatial resolution and data rate, bandwidth, and component compactness, but the lack of sufficient source power has not been adequately solved. High power radiation sources in the THz range also have considerable application in advanced fusion plasma diagnostics. Work is presented herein on the design of waveguide components and a high efficiency pulse modulator to support the development of integrated high power sources for fusion diagnostics and other applications.