Development of MegaWatt Traveling Wave Antennas for Plasma Heating at the DIII-D

In this paper, we present an overview of the development of two high power traveling wave antennas (TWAs) termed the “comb-line” and the “finline” for launching fast and slow waves in plasmas. The comb-line antenna which has been deployed at the DIII-D National Fusion Facility tokamak can couple megawatt (MW) level RF power into the tokamak plasma with
$\sim$
2% reflected power and
$\sim$
2% dissipated power per array element at its design frequency, 476 MHz. A prototype of the finline antenna which has been designed to launch lower hybrid slow waves at 4.6 GHz, has reflection coefficient below 10% with 1.8 dB insertion loss.