This study uses the diversity of materials at known locations in the Experimental Advanced Superconducting Tokamak (EAST) to extract, local information on which plasma-surface interaction processes are dominant during Ion Cyclotron Resonance Heating (ICRH) (near vs far field effects). Metallic impurity content is indicated by the intensity of impurity line emissions observed with a fast-time-response extreme ultraviolet (EUV) spectrometer, normalized to line-averaged plasma density, i.e. Iimp/ne. Parametric dependencies are explored over scans of ICRH and LH (Lower Hybrid) power and for different toroidal phasings between straps, strap power balance, and magnetic configurations. This diversity of behavior is interpreted as the signature of different physical processes. Before 2017, as only the upper divertor region contained tungsten (W), the W content in the core used to increase a lot when moving from lower (LSN) to upper single null (USN) configurations, and was correlated with the total injected power rather than the ICRH power. Molybdenum (Mo), covering the part of the inner wall facing one ICRF antenna appear sensitive to this antenna power and phasing benchmarked by modelling suggesting a probable interaction due to residual ICRF waves crossing the plasma. Materials close and magnetically-connected to an active antenna show better correlation with ICRF antenna electrical tuning than those which are far away, or not connected. This is particularly the case with W since 2018, because the limiter tiles of the LH launchers were changed from graphite to tungsten. In these latter conditions, it is shown that W sources at the mid-plane (equatorial plane) contribute to a significant fraction of the core contamination by tungsten (25% in ohmic regime, and more during ICRH).

中文翻译：

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EAST 中 ICRH 加热 L 模式放电期间的金属杂质含量行为

本研究使用实验性先进超导托卡马克 (EAST) 中已知位置的材料多样性来提取有关离子回旋共振加热 (ICRH)（近场效应与远场效应）期间等离子体-表面相互作用过程占主导地位的局部信息。金属杂质含量由使用快速响应极紫外 (EUV) 光谱仪观察到的杂质线发射强度表示，归一化为线平均等离子体密度，即 Iimp/ne。在 ICRH 和 LH（下混合）功率扫描以及带之间的不同环形相位、带功率平衡和磁性配置中探索了参数依赖性。这种行为的多样性被解释为不同物理过程的特征。2017 年之前，由于只有上部偏滤器区域含有钨 (W)，当从较低的 (LSN) 配置移动到较高的单零 (USN) 配置时，纤芯中的 W 含量会增加很多，并且与总注入功率而非 ICRH 功率相关。钼 (Mo)，覆盖面向一个 ICRF 天线的内壁部分，似乎对该天线功率和定相敏感，通过建模表明可能是由于残余 ICRF 波穿过等离子体而产生的相互作用。与距离较远或未连接的材料相比，靠近并磁性连接到有源天线的材料与 ICRF 天线电调谐显示出更好的相关性。自 2018 年以来，W 的情况尤其如此，因为 LH 发射器的限制器瓦片从石墨改为钨。在后一种情况下，