In this paper, the edge plasma parameters, including the electron temperature (Te), electron density (ne), plasma potential (ϕp), radial electric field (Er) and the corresponding fluctuations in the Sino-united spherical tokamak (SUNIST) have been systematically measured using Langmuir probe arrays. The characteristics of the edge electrostatic fluctuations and the turbulence-induced transport are experimentally investigated. The results show that a naturally formed Er × Bϕ poloidal velocity shear layer (VSL) exists near the radial location of the limiter. Wavenumber spectrum analyses show that edge fluctuations have a radial propagation character of the drift wave turbulence, with a characteristic radial phase velocity vphr ∼ 0.7 km s−1 in the scrape-off-layer and vphr ∼ 0.9–1.4 km s−1 at plasma edge, suggesting that the edge turbulence may originate from the core and propagate to the edge in an intermittent pattern. A radial profile of the toroidal flow velocity Mach number has been observed whose maximum is just located at the VSL position, which may imply a possible relation between the poloidal shear flow and the toroidal plasma flow in SUNIST.
本文利用朗缪尔探针阵列对Sino-联合球形托卡马克（SUNIST）中的边缘等离子体参数，包括电子温度（Te）、电子密度（ne）、等离子体电位（ϕp）、径向电场（Er）及其相应的涨落进行了系统测量。实验研究了边缘静电涨落的特性及湍流输运。结果表明，在限制器径向位置附近自然形成了Er × Bϕ 极向剪切流层（VSL）。波数谱分析显示，边缘涨落具有漂移波湍流的径向传播特征，在刮削层中特征径向相速度 vphr ∼ 0.7 km s⁻¹，在等离子体边缘处 vphr ∼ 0.9–1.4 km s⁻¹，这表明边缘湍流可能起源于芯部并以间歇性模式向边缘传播。观测到环向流速马赫数的径向分布，其最大值恰好位于VSL位置，这可能意味着SUNIST中极向剪切流与环向等离子体流之间存在潜在关联。