A Dip Structure in the Intrinsic Toroidal Rotation Near the Edge of the Ohmic Plasmas in EAST  

作　　者：徐国盛 V.NAULIN 万宝年 郭后扬 张炜 常加峰 颜宁 丁斯晔 张凌 王亮 刘少承 刘鹏 蒋敏 汪惠乾 J.Juul RASMUSSEN A.H.NIELSEN 肖持进 高翔 胡立群 朱思铮 吴振伟 钱金平 龚先祖 

机构地区：[1]Institute of Plasma Physics,Chinese Academy of Sciences [2]Association Euratom-Risφ DTU [3]Tri Alpha Energy,Rancho Santa Margarita [4]Plasma Physics Laboratory,University of Saskatchewan,Saskatoon,SK S7N 5E2,Canada

出　　处：《Plasma Science and Technology》2011年第4期397-404,共8页等离子体科学和技术（英文版）

基　　金：supported by National Natural Science Foundation of China(Nos.11075181,10725523,10721505,10990212 and 10605028);the ITER project of China(No.2010GB104001)

摘　　要：Ion＇s toroidal velocity, vt, in both the outermost 4 cm of the confined region and the scrap-off layer of Ohmic L-mode plasmas in EAST was measured using Mach probes. At about 1 cm inside the separatrix a local minimum in vt was observed, from which a cocurrent rotation increased both inwards and outwards. The radial width of the vt dip was 1 cm to 2 cm, and both the density and electron temperature profiles exhibited steep gradients at this dip position. It was observed in both divertor and limiter configurations. To find out its origin, the toroidal torques induced by neutral friction, neoclassical viscosity, collisional perpendicular shear viscosity, ion orbit loss and turbulent Reynolds stress were estimated using the measured parameters. Our results indicate that in this particular parameter regime the neutral friction was the dominant damping force. The calculated cocurrent toroidal torque by the neoclassical viscosity dominates over those from the collisional perpendicular shear viscosity, ion orbit loss and turbulent Reynolds stress. These results are potentially important for the understanding of boundary conditions for the intrinsic toroidal momentum in tokamak plasmas.Ion＇s toroidal velocity, vt, in both the outermost 4 cm of the confined region and the scrap-off layer of Ohmic L-mode plasmas in EAST was measured using Mach probes. At about 1 cm inside the separatrix a local minimum in vt was observed, from which a cocurrent rotation increased both inwards and outwards. The radial width of the vt dip was 1 cm to 2 cm, and both the density and electron temperature profiles exhibited steep gradients at this dip position. It was observed in both divertor and limiter configurations. To find out its origin, the toroidal torques induced by neutral friction, neoclassical viscosity, collisional perpendicular shear viscosity, ion orbit loss and turbulent Reynolds stress were estimated using the measured parameters. Our results indicate that in this particular parameter regime the neutral friction was the dominant damping force. The calculated cocurrent toroidal torque by the neoclassical viscosity dominates over those from the collisional perpendicular shear viscosity, ion orbit loss and turbulent Reynolds stress. These results are potentially important for the understanding of boundary conditions for the intrinsic toroidal momentum in tokamak plasmas.

关 键 词：intrinsic rotation turbulent Reynolds stress toroidal torques neutral friction 

分 类 号：TL612[核科学技术—核技术及应用]