Recent ICRF coupling experiments on EAST

Abstract

Recent ion cyclotron resonance frequency (ICRF) coupling experiments for optimizing ICRF heating in high power discharge were performed on EAST. The coupling experiments were focus on antenna phasing and gas puffing, which were performed separately on two ports of the ion cyclotron resonance heating (ICRH) system of EAST. The antenna phasing was performed on the I-port antenna, which consists of four toroidally spaced radiating straps operating in multiple phasing cases; the coupling performance was better under low wave number  | | k (ranging from 4.5 to 6.5). By fuelling the plasma from gas injectors, placed as uniformly spaced array from top to bottom at each side limiter of the B-port antenna, which works in dipole phasing, the coupling resistance of the B-port antenna increased obviously. Furthermore, the coupling resistance of the I-port antenna was insensitive to a smaller rate of gas puffing but when the gas injection rate was more than a certain value (>10 21 s −1 ), a sharp increase in the coupling resistance of the I-port antenna occurred, which was mainly caused by the toroidal asymmetric boundary density arising from gas puffing. A more specific analysis is given in the paper.

Recent results of fusion triple product on EAST tokamak

“…With this change, it is expected that the NBI heating will be more efficient and can drive higher toroidal rotation. On the other hand, one ICRF antenna has been modified and can produce wave with lower wave number, which is more efficient for plasma-wave coupling in EAST plasma [32]. All these new equipments will be commissioned in a 2021 campaign and expected to provide more power on ion heating and to drive higher toroidal rotation in future experiments.…”

Physical design and recent experimental results of the new ICRF antenna on EAST

“…The B-port antenna consists of toroidal two-loop straps with = 12.6 m −1 at dipole phasing, while the I-port antenna features toroidal four-folded straps with = 13.6 m −1 at (0, π, 0, π) phasing. But the previous experiment data on EAST have shown that the coupling of these original antennas is insufficient [11,12]. The low coupling of antenna will increase the standing wave voltage on transmission line and limit the ICRF system power capacity on EAST.…”

Advances in experimental research towards high confinement and steady state operation on the Experimental Advanced Superconducting Tokamak

“…此外, 每路天线馈线均布设电压电流探 针, 用于传输线阻抗监测 [22] , 还采用了传输线水冷技术 来实现系统长时间稳态运行. 通过优化波与等离子体耦 合, 以及开展ICRH, LHCD, ECRH协同加热, 在高约束 等离子实验研究方面取得了重大突破 [23,24] .…”