Non-ambipolar Transport by Trapped Particles in Tokamaks

Park, J.K. . Boozer, A.H and . Menard, J.E

关键词: MAGNETIC FIELDS;    PERFORMANCE;    PRECESSION;    RESOLUTION;    SENSITIVITY;    TRANSPORT Diffusion;    Magnetic Field;    Transport Theory;    Tokamaks;   

DOI  :  10.2172/950505
RP-ID  :  PPPL-4375
PID  :  OSTI ID: 950505
Others  :  TRN: US0902340

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 】

Small non-axisymmetric perturbations of the magnetic field can greatly change the performance of tokamaks through non-ambipolar transport. A number of theories have been developed, but the predictions were not consistent with experimental observations in tokamaks. This Letter provides a resolution, with a generalized analytic treatment of the non-ambipolar transport. It is shown that the discrepancy between theory and experiment can be greatly reduced by two effects: (1) The small fraction of trapped particles for which the bounce and precession rates resonate. (2) The non- axisymmetric variation in the field strength along the perturbed magnetic field lines rather than along the unperturbed magnetic field lines. The expected sensitivity of ITER to non-axisymmetries is also discussed.