Recent advancements of microwave imaging diagnostic at the DIII-D tokamak*

The DIII-D tokamak's microwave imaging diagnostic capabilities have been upgraded to improve the study and operation of ITER baseline plasma physics. Utilizing system-on-chip technology, customized and compact microwave components have been developed for various diagnostic systems. Notably, the W-band Electron Cyclotron Emission Imaging (ECEI) diagnostic which has been in use since 2019 to visualize the two-dimensional dynamics of transient MHD (Magnetohydrodynamic) events, including Sawtooth Crash, Alfven Eigenmode, and Edge Localized Mode. New features for 2024 include remote control features added to meet evolving fusion diagnostics standards and the installation of 117.5 GHz notch filters to ensure safe operation during gyrotron heating. F-band receiver chips (110-140 GHz) have been developed and are to be packaged and installed in 2024 for high field side ECEI measurements. In January 2024, a next generation V-band (55-75 GHz) Microwave Imaging Reflectometer (MIR) system will be installed, with improved transmitter power and signal-to-noise ratios, permitting pedestal region high-resolution imaging of electron density fluctuations. The combined MIR-ECEI instrument enables simultaneous measurement of electron density and temperature fluctuations, facilitating multi-field physics investigation in MHD/turbulence transport studies.