Status of LHFW research in KSTAR and Future Plan

The LHFW research has been conducted on KSTAR after successful feasibility study on VEST. With a newly developed SWA (Slotted Waveguide Antenna) of 2.45 GHz, for the first time LHFW experiment was carried out in the 2024 KSTAR campaign. The preliminary coupling experiment result shows that the LHFW (Lower Hybrid Fast Wave) can be coupled with short ROG (Radial Outer Gap) and high elongation (kappa) configuration in H-mode plasmas, which is in agreement with the coupling simulation characteristics of slow and fast wave with density. Unfortunately, the SWA was damaged by mis-alignment with poloidal limiter originated from chamber port length. A more thermal & sputtering resistant SWA is under development and it will be installed before the 2025 KSTAR campaign. If the LHFW coupling is confirmed on upcoming KSTAR campaign, higher power experiment will be pursued aiming for LHFW current drive.