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Radio frequency (RF) power in the ion cyclotron range of frequencies (ICRF) is one of the primary auxiliary heating techniques for Experimental Advanced Superconducting Tokamak (EAST). In this paper, we will present an overview of the main experimental results from recent campaign on EAST. 1) A dedicated experiment for more than 10MW operations has been carried out on EAST. The major aspects linked to the use of the EAST auxiliary heating systems: ICRF,LHCD and NBI are presented with emphasis on ICRF and LH. The challenges for ICRF coupling on EAST will be described at the low densities typically used for long pulse operation with lithium wall conditioning. 2)This paper also summarizes effects of ICRF power on LH coupling and modification of heat loads on EAST. 3) Co-current rotation driven by ICRF are observed in both L-mode and H-mode discharges. Co-current rotation can be generated by ICRF heating in LHCD plasma. Different rotation behavior observed in LHCD discharges. ICRF can also induce counter-current rotation in LHCD L-mode discharges. 4) A high-frequency magnetic probes (HFBs) system has been developed and successfully applied to detect ion cyclotron emission (ICE) in D-NBI injection experiments in the 2018 experimental campaign of EAST. ICE driven by fast D-NBI ions and fusion born ions are observed on EAST.5) In Hydrogen minority in Deuterium plasma, the interaction of fast wave and fast D-NBI ions is detected on EAST. Acceleration of fast D ions is confirmed by increased neutron yield. [ABSTRACT FROM AUTHOR]

The research of EAST program is mostly focused on the development of high performance steady state scenario with ITER-like poloidal configuration and RF-dominated heating schemes. With the enhanced ITER-relevant auxiliary heating and current drive systems, the plasma profile control by coupling/integration of various combinations has been investigated, including lower hybrid current drive (LHCD), electron cyclotron resonance heating (ECRH) and ion cyclotron resonance heating (ICRH). The 12 MW ICRH system has been installed on EAST. Heating and confinement studies using the Hydrogen Minority Heating scheme have been investigated. One of the importance challenges for EAST is coupling higher power into the core plasma, experiments including changing plasma position, electron density, local gas puffing and antenna phasing scanning were performed to improve ICRF coupling efficiency on EAST. Results show that local gas injection and reducing the k∥ can improve the coupling efficiency directly. By means of the 4.6 GHz and 2.45 GHz LHCD systems, H-mode can be obtained and sustained at relatively high density, even up to ne ~ 4.5 × 1019 m-3, where a current drive effect is still observed. Meanwhile, effect of source frequency (2.45GHz and 4.6GHz) on LHCD characteristic has been studied on EAST, showing that higher frequency improves penetration of the coupled LH (lower hybrid) power into the plasma core and leads to a better effect on plasma characteristics. Studies demonstrate the role of parasitic effects of edge plasma in LHCD and the mitigation by increasing source frequency. Experiments of effect of LH spectrum and plasma density on plasma characteristics are performed, suggesting the possibility of plasma control for high performance. The development of a 4MW ECRH system is in progress for the purpose of plasma heating and MHD control. The built ECRH system with 1MW source power has been successfully put into use on EAST in 2015. H-mode discharges with L-H transition triggered by ECRH injection were obtained and its effects on the electron temperature, particle confinement and the core MHD stabilities were observed. By further exploring and optimizing the RF combination for the sole RF heating and current drive regime, fully non-inductive H-mode discharges with Vloop~0V has progressed steadily in the 2016 campaign. The overview of the significant progress of RF dominated experiments is presented in this paper. [ABSTRACT FROM AUTHOR]

The ICRF heating system on EAST upgraded by active cooling aims for long pulse operation. In this paper, the main technical features of the ICRF system are described. One of a major challenges for long pulse operation is RF-edge interactions induced impurity production and heat loading. In EAST, ICRF antenna protections and Faraday screen bars damaged due to LH electron beam are found. Preliminary results for the analysis of the interaction between LHCD and ICRF antenna are discussed. Increase of metal impurities in the plasma during RF pulse and in a larger core radiation are also shown. These RF-edge interactions at EAST and some preliminary results for the optimizing RF performance will be presented. [ABSTRACT FROM AUTHOR]

Research on HT-7 tokamak focuses on exploiting the IBW-heated plasmas mainly to understand heating, active control of profiles and the synergetic interaction with LHCD. Both on-axis and off-axis electron heating with global peaked and localize steep electron pressure profile were realized. The operation of IBW and LHCD synergetic discharges were obtained and optimized through moving the IBW resonant layer to maximize the plasma performance and to avoid MHD activity. Experimental Advanced Superconducting Tokamak (EAST) has been built to perform advanced tokamak research in high performance regime and to explore methods for achieving a steady-state operation for a tokamak fusion reactor at ASIPP. This talk reports an overview of ICRF wall conditioning in HT-7 and EAST during recent campaigns. [ABSTRACT FROM AUTHOR]