2023 Status of the ECH System on DIII-D

The Electron Cyclotron Heating (ECH) system on DIII-D currently consists of five non-depressed collector 110-GHz Communications and Power Industries (CPI) gyrotrons which combine to inject a total of 3.2 MW of RF power into the plasma via eight transmission lines and four equatorial launchers. The available ECH power increased by 700 kW from last year after the refurbished gyrotron "Han" was successfully commissioned and added to operations earlier this year. Additionally, two more 110-GHz CPI gyrotrons will be joining operations by the start of the FY24 plasma campaign, potentially increasing the available ECH power to over 4.5 MW. The first gyrotron, "NASA", is a refurbished depressed collector gyrotron that is currently undergoing the testing and conditioning process at DIII-D. The second gyrotron, "Thor", is a new non-depressed collector gyrotron that is scheduled to arrive at DIII-D this summer after undergoing repairs by the manufacturer that interrupted its conditioning process at DIII-D earlier this year. Furthermore, DIII-D is also expected to receive its first two new depressed collector gyrotrons from Thales in 2024 and 2025, which are each designed to generate a maximum power of 1 MW at a frequency of 117.5 GHz.