Upgrades and New Features to the ECH System on DIII-D

The Electron Cyclotron Heating system on DIII-D currently consists of four 110 GHz gyrotrons which combine to inject a total of 2.5 MW into the plasma. Over this past year, the ECH system has experienced several key upgrades. First, a building expansion for the ECH gyrotron vault is nearing completion, and this will provide a total of 3 additional gyrotron sockets. Another recent upgrade was the installation and commissioning of one new top launcher system and one upgraded top launcher mirror assembly for increased current drive capabilities. New instrumentation and controls were installed to support the two top launchers as well as refurbishing and upgrading the existing ECH launchers instrumentation. Some of the new instrumentation features for the top launchers include temperature sensors and arc detection. We have also completed the conditioning process for our newest gyrotron, Yoda, and it was accepted into operations earlier this year with a generated power of 780 kW and a pulse length of 5 s. Lastly, we are expecting to receive 2 repaired gyrotrons and 1 new gyrotron by the end of 2022. This will bring the total number of gyrotrons on DIII-D up to 7, and this is expected to increase the total ECH power to over 4 MW.