Scrape-off layer (SOL) profiles and turbulence in ion cyclotron range of frequency (ICRF)-heated plasmas are investigated by the reciprocating probe diagnostic system (FRPs) and gas puff imaging (GPI) diagnostic in EAST. A radio-frequency (RF) sheath potential reaching up to 100 V is identified proximate to the ICRF antennas. Notably, the amplitude of this RF sheath potential escalates in response to rising ICRF power and inversely with plasma density. When a RF sheath is present in the far SOL, a pronounced density ‘shoulder’ forms in front of the ICRF antennas, while the ‘shoulder’ fade away as the antenna and associated RF sheath shift outwards. A strong E _r shear is revealed by measurements from both FRPs and GPI. Analysis of the poloidal wave number-frequency spectrum reveals suppression of high-frequency turbulence in the far SOL due to the RF sheath. This effect is manifested in the reduced autocorrelation time τ _c and reduced average blob size δ _blob of the SOL plasma. Intriguingly, the poloidal propagation direction of the low-frequency turbulence reverses from the electron to the ion diamagnetic drift direction at the RF sheath location. A surge of tungsten impurity is potentially attributed to the heightened interaction between the SOL plasmas and the wall material. Shifting the ICRF antennas outward, to alleviate heat spots, results in the relocation of the RF sheath to the shaded region of the main limiter. This shift amplifies the radial velocity of blobs in the far SOL and concurrently diminishes the SOL density when compared to conditions without ICRF injection. The properties of ion saturation current fluctuations are consistent with the stochastic model predictions.

中文翻译：

---

EAST 中 ICRF 加热等离子体中 SOL 剖面和湍流的表征

通过 EAST 中的往复探针诊断系统 (FRP) 和气体喷吹成像 (GPI) 诊断，研究了离子回旋加速器频率范围 (ICRF) 加热等离子体中的刮落层 (SOL) 轮廓和湍流。在 ICRF 天线附近发现射频 (RF) 鞘电位高达 100 V。值得注意的是，该 RF 鞘层电势的幅度随着 ICRF 功率的升高而升高，并且与等离子体密度成反比。当远 SOL 中存在 RF 护套时，ICRF 天线前面会形成明显的密度“肩”，而“肩”会随着天线和相关 RF 护套向外移动而逐渐消失。一个强壮的乙 _r剪切力通过 FRP 和 GPI 的测量来揭示。极向波数频率谱的分析揭示了由于射频鞘层对远太阳系中高频湍流的抑制。这种效果体现在自相关时间的减少τ _c并减少平均斑点大小δ SOL 等离子体的_斑点。有趣的是，低频湍流的极向传播方向在射频鞘层位置从电子反向到离子抗磁漂移方向。钨杂质的激增可能归因于 SOL 等离子体和壁材料之间增强的相互作用。将 ICRF 天线向外移动以减轻热点，导致 RF 护套重新定位到主限制器的阴影区域。与没有 ICRF 注入的条件相比，这种转变放大了远 SOL 中斑点的径向速度，同时降低了 SOL 密度。离子饱和电流波动的特性与随机模型预测一致。