Neoclassical transport due to resonant magnetic perturbations in DIII-D and NSTX

We investigate the role of neoclassical physics in particle and energy transport during the application of resonant magnetic perturbations (RMPs) to suppress the edge localised modes in a tokamak. The drift kinetic code NEO is used to evaluate the neoclassical transport in DIII-D plasmas where RMPs are applied. The magnetic field given as an input to NEO is calculated using extended MHD code M3D-C1 and includes nonlinear resistive plasma response in realistic geometry, dissapiation, and sources.

The study indicates a dramatic increase of the neoclassical particle and energy fluxes in the presence of the RMPs and is on the same order as experimentally inferred fluxes, highlighting the importance of neoclassical transport in the edge transport when RMPs are present. The calculated neoclassical fluxes in DIII-D plasmas are found to be closely correlated with the observations of density pump-out over a range of RMP spectra. Also, these calculations show that nonlinear MHD simulations are essential at high RMPs to satisfactorily model the perturbed magnetic geometry in the pedestal region.

We also study the impact of RMPs and lithium (Li) content on neoclassical transport in Li coated ELM suppressed NSTX discharges using the coupled M3D-C1/NEO setup.