Performance of newly developed ICRF antennas on EAST

One of the keys to successful ion cyclotron range of frequency (ICRF) heating in Experimental Advanced Superconducting Tokamak (EAST) is maximizing the coupled power through evanescent layer in both L-mode and H-mode discharges. Increasing coupling efficiency is critical. To reach high power operation, two newly developed antennas have been tested on EAST. Here, we describe the key design features of the antenna and assess its performance by comparison with old four-strap antenna. The key design features are lower k|| spectrum, two current strap configuration, and field aligned faraday screen. The design for the newly developed antenna is balance between geometrical constraints and physics requirements on EAST. The faraday screen rods are fully aligned with the total magnetic field. To reduce the maximum voltage further in the transmission line, an impedance transformer in the vacuum transmission line was used. With these modifications, the loading is increased by 3 times and the heating efficiency is increased by 2-3 times as compared with old four-strap antenna in both L-mode and H-mode discharges. 4.0MW of the maximum injected power with these two antennas have been achieved at the maximum voltage of 15 kV in the transmission lines. We will report latest experimental results from these two ICRF antennas in the recent campaign of EAST.