ICRF antenna designs for CIT and alcator C-Mod
AIP Conference Proceedings
An ion cyclotron range of frequencies (ICRF) launcher for the Compact Ignition Tokamak (CIT) has been designed. This launcher incorporates four current straps in a 2 x 2 configuration. The current straps consist of end-fed loops that are grounded in the middle. An antenna similar in geometry, size, and feed configuration to a single strap of the CIT launcher will be built for use on Alcator C-Mod. The design must provide maximum power levels of 4 MW/port for CIT and 2 MW/port for C-Mod, pulse
... for C-Mod, pulse lengths of 5-10 s for CIT and I s for C-Mod, and power densities up to 2 kW/cm 2 . The design uses a Faraday shield consisting of Inconel rods with mechanically attached graphite tiles; the shield and the current strap are cooled by radiating to a gas-cooled backplane. A feed configuration compatible with the end-fed antenna design has been developed and features tunability in three bands in the range 65-130 MHz. It uses an external resonant loop with integral tuning elements. It has been designed to maximize power handling capabilities, minimize space requirements, and facilitate remote handling.