Delta f Monte Carlo Calculation Of Neoclassical Transport In Perturbed Tokamaks
Authors: Kimin Kim, Jong-Kyu Park, Gerrit Kramer and Allen H. Boozer
Abstract:
Non-axisymmetric magnetic perturbations can fundamentally change neoclassical transport in
tokamaks by distorting particle orbits on deformed or broken flux surfaces. This so-called non-ambipolar transport is highly complex, and eventually a numerical simulation is required to achieve
its precise description and understanding. A new deltaf particle code (POCA) has been developed
for this purpose using a modi ed pitch angle collision operator preserving momentum conservation.
POCA was successfully benchmarked for neoclassical transport and momentum conservation in
axisymmetric con guration. Non-ambipolar particle flux is calculated in the non-axisymmetric
case, and results show a clear resonant nature of non-ambipolar transport and magnetic braking.
Neoclassical toroidal viscosity (NTV) torque is calculated using anisotropic pressures and magnetic
fi eld spectrum, and compared with the generalized NTV theory. Calculations indicate a clear B2
dependence of NTV, and good agreements with theory on NTV torque pro les and amplitudes
depending on collisionality.
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Submitted to: Physics of Plasmas (April 2012)
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Download PPPL-4752 (pdf 789 KB 9 pp)
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