High field side LHCD launcher study for KSTAR

Abstract Upgrading to a lower hybrid current drive (LHCD) system on the high field side (HFS) or top launcher is under consideration for efficient current drive of KSTAR. The HFS or top launcher needs to be compact because of the tight and congested space at the inboard and near the upper divertor. This paper introduces a study of compact LHCD antenna development, and includes a brief review of a traveling wave antenna cold model and comparison with the new design of a resonant type slotted waveguide array in combination with a passive active multijunction, i.e. SWA PAM. The traveling wave antenna has structural simplicity, while SWA PAM has N || adjustment capability.