Speaker
Description
The ECH gyrotron system at DIII-D currently consists of six 110-GHz Communications and Power Industries (CPI) diode tubes available for operation in the 2024 experimental campaign. The RF power is injected into DIII-D via four dual launchers (built by Princeton Plasma Physics Laboratory) located above the mid-plane of the machine. Eight existing transmission lines route from the four dual launchers to the existing ECH vault, where all six operational gyrotrons are currently located. DIII-D is currently preparing to install a fifth dual launcher and two transmission lines to accommodate new multifrequency (104/137/170 GHz) gyrotrons for operations in 2026. The two new gyrotrons will be placed in the ECH Expansion Vault adjacent to the existing ECH Vault. The new launcher will be placed symmetrically to the others at a port below the mid-plane with 60.3mm diameter, corrugated, vacuum transmission lines (built by General Atomics) routed from the tokamak, over the roof of the facility, to the ECH Expansion Vault. The installation of these transmission lines will employ a new laser alignment system, a low power HE11 mode content test, ultra-high vacuum leak checks, and full ECH power conditioning tests with the new gyrotrons. With these two new systems installed, and with 117.5 GHz gyrotrons (built by Thales Group) planned to fill two positions in the original ECH vault, the total number of gyrotrons at DIII-D will come to 10.
