HL-2A装置中的带状流三维特性研究和探针设计

HL-2A装置边缘等离子体测地声模带状流的三维特征采用外中平面上三组三台阶探针阵列组成具有环向、极向和径向分辨的独特结构的探针系统进行了研究.其中两组具有极向距离为65mm的三台阶5探针阵列组成极向带状流10探针组，另一组电动式带状流6探针阵列与带状流10探针组之间的环向距离为800mm. 此外，采用快速往复气动6探针组研究了磁分界面附近的温度、密度、雷诺协强及其径向分布.在HL-2A装置上同时观测到测地声模带状流(频率f=7kHz)的极向和环向对称性(m≈0，n 关键词： 三台阶式ZF探针 带状流 三维空间结构

Study of three dimensional zonal flows characteristic and novel probe design in HL-2A

Three dimensional(3-D) features of geodesic acoustic mode zonal flows (GAMZF) were first determined with novel three-step zonal flow probes (TSZFP) at the edge of the HL-2A Tokamak plasmas. Three arrays of TSZFP were located 65mm and 800mm apart. The poloidal mode (m～0) and toroidal mode (n～0) of electric potential and field perturbations were simultaneously determined for the first time. Corresponding frequencies were estimated as 7kHz，which are in good agreement with theoretical prediction. The radial scale lengths of ZF were 24—42cm. The formation mechanism of the flows is identified to be nonlinear three wave coupling between high frequency turbulent fluctuations and the flows. The regulating effect of the flows on the ambient turbulent fluctuations was also demonstrated. The Reynolds stress driven by edge fluctuation is one of the main reasons driving the poloidal flow. It is also verified that the radial gradient of Reynolds stress can drive zonal flows.