Comparison of Poloidal Velocity Meassurements to Neoclassical Theory on the National Spherical Torus Experiment

Bell, R E ; Kaye, S M ; Kolesnikov, R A ; LeBlance, B P ; Rewolldt, G ; Wang, W X

关键词: ATOMIC PHYSICS;    CHARGE EXCHANGE;    ELECTRIC FIELDS;    IMPURITIES;    RECOMBINATION;    SPECTROSCOPY;    TRANSPORT;    TURBULENCE;    VELOCITY Charge Exchange;   

DOI  :  10.2172/981659
RP-ID  :  PPPL-4508
PID  :  OSTI ID: 981659
Others  :  TRN: US1004436

学科分类：原子、分子光学和等离子物理

美国|英语

来源: SciTech Connect

【 摘 要 】

Knowledge of poloidal velocity is necessary for the determination of the radial electric field, Er, which along with its gradient is linked to turbulence suppression and transport barrier formation. Recent measurements of poloidal flow on conventional tokamaks have been reported to be an order of magnitude larger than expected from neoclassical theory. In contrast, recent poloidal velocity measurements on the NSTX spherical torus [S. M. Kaye et al., Phys. Plasmas 8, 1977 (2001)] are near or below neoclassical estimates. A novel charge exchange recombination spectroscopy diagnostic is used, which features active and passive sets of up/down symmetric views to produce line-integrated poloidal velocity measurements that do not need atomic physics corrections. Local profiles are obtained with an inversion. Poloidal velocity measurements are compared with neoclassical values computed with the codes NCLASS [W. A. Houlberg et al., Phys. Plasmas 4, 3230 (1997)] and GTC-Neo [W. X. Wang, et al., Phys. Plasmas 13, 082501 (2006)], which has been updated to handle impurities. __________________________________________________