Non-ambipolar Transport by Trapped Particles in Tokamaks

[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.

[发布日期] 2009-01-27

[学科分类] 原子、分子光学和等离子物理

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