Unified modeling of both resonant and non-resonant neoclassical transport under non-axisymmetric magnetic perturbations in tokamaks

Y. Sun, X. Li, K. He, K. C. Shaing

Research output: Contribution to journalArticle

Abstract

A numerical model for neoclassical transport under nonaxisymmetric magnetic perturbations in low collisionality plasmas in tokamaks is developed. To take into account bounce-drift resonances and magnetic drift effects, a Fourier decomposition of the drift kinetic equation in new coordinates, rather than bounce average of it, is employed. A pitch angle scattering collisional operator is used to keep accuracy in the nonresonant regimes or resonant plateau regimes with resonant pitch near pitch space boundaries. Full toroidal geometry effects are also included to increase the accuracy in the modeling of neoclassical transport in the resonant regimes. Neoclassical transport in the most important collisionless regimes, including resonant super-banana plateau and bounce-drift resonances regimes, nonresonant 1/ν and ν - ν regimes, and the transitions between them, can be modeled simultaneously in this model by numerically solving the drift kinetic equation. By application to the neoclassical toroidal viscosity modeling in one discharge in the EAST tokamak, it is found that the bounce-drift resonances dominate the contributions near the plasma core where the plasma E → × B → drift frequency is close to the bounce frequency, while the precessional resonance dominates the contribution near the edge pedestal top where the E → × B → drift frequency is close to zero.

Original languageEnglish
Article number0725041
JournalPhysics of Plasmas
Volume26
Issue number7
DOIs
Publication statusPublished - 2019 Jul 1

All Science Journal Classification (ASJC) codes

  • Condensed Matter Physics

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