Overview of the ICRF antenna coupling experiments on EAST

Experimental verification of ion cyclotron range of frequencies (ICRF) wave coupling is crucial to gain insight into the physics of the improvement of ICRF antenna coupling. The progress of ICRF antenna coupling experiments on EAST has been reported since 2007. The dependence of the loading resistance on the target plasma parameters, operational regimes and synergic heating scenarios on EAST are reviewed. Results show that the antenna coupling resistance Rc in L-mode regime meets the relation of Rc ∝ exp(−1.5k∥xc), which is in good agreement with the simulation results with a perfectly matched layer method, where k∥ is the dominant launched parallel wave number and xc is the distance of the ICRF antenna and fast wave cut-off layer. Low plasma current, gas puff in the magnetic connections with the ICRF antenna and lower hybrid wave/electron cyclotron heating are beneficial for improving ICRF antenna coupling. The antenna coupling has a strong response during large edge-localized modes (ELMs) but it becomes steady state during ELM free. The study of ICRF antenna coupling under various parameters is helpful to optimize the ICRF wave heating scenario and understand the physical mechanisms which influence the ICRF wave coupling in plasmas.