New ICRF antenna Characterization and Performance in EAST

Coupling and Heating associated with ion cyclotron range of frequency (ICRF) heating was a major challenge to ICRF utilization in the past on EAST. In order to increase the antenna loading and thereby increase the heating, a lower k parallel spectrum ICRF antenna has been designed and installed for EAST 2021 experimental campaign. In order to decrease the maximum voltage on the transmission line, we developed an impedance transformer near the antenna port. The new antenna with 3D curved Faraday screens and current strap is also expected to improve further the coupling. Using the old B-port antenna as a reference, the coupling and heating efficiency are significantly higher for the new antenna than the old B-port antenna. The coupling loading and heating efficiency of the new ICRF antenna is ∼3-7 times greater than the old B-port antenna. The plasma stored energy is increased by 30 kJ/MW in the high β_p H-mode discharges . The improved performance is consistent with simulations indicating that the new design of ICRF antenna has greatly improved the coupling relative to the old antennas. In addition, the long pulse operations of 1.1MW/60s, 1.5MW/40s and 1.8MW/22s are achieved for the new ICRF antenna in the high β_p H-mode discharges. Here, we will report results on the coupling characterization of new ICRF antenna and an overview of the main results from new ICRF antenna in the EAST 2021 experimental campaign.