Open AccessNumerical Verification of Bounce Harmonic Resonances in Neoclassical Toroidal Viscosity for Tokamaks
Author(s) -
Jong-Kyu Park and Allen H. Boozer Kimin Kim
Publication year - 2013
Language(s) - English
Resource type - Reports
DOI - 10.2172/1074353
Subject(s) - tokamak , toroid , harmonic , physics , plasma , torque , rotation (mathematics) , ideal (ethics) , viscosity , aspect ratio (aeronautics) , mechanics , mathematics , nuclear physics , quantum mechanics , geometry , law , optoelectronics , political science
This Letter presents the rst numerical veri cation for the bounce-harmonic (BH) resonance phenomena of the neoclassical transport in a tokamak perturbed by non-axisymmetric magnetic elds. The BH resonances were predicted by analytic theories of neoclassical toroidal viscosity (NTV), as the parallel and perpendicular drift motions can be resonant and result in a great enhancement of the radial momentum transport. A new drift-kinetic #14;f guiding-center particle code, POCA, clearly veri ed that the perpendicular drift motions can reduce the transport by phase-mixing, but in the BH resonances the motions can form closed orbits and particles radially drift out fast. The POCA calculations on resulting NTV torque are largely consistent with analytic calculations, and show that the BH resonances can easily dominate the NTV torque when a plasma rotates in the perturbed tokamak and therefore is a critical physics for predicting the rotation and stability in ITER.