Joey Schmidt, UT-Austin

"Gyrokinetic investigation of pedestal transport on NSTX"

Abstract: In the NSTX-U spherical tokamak, the addition of lithium coatings sprayed onto several plasma facing components improves confinement and minimizes edge localized modes (ELMs). We use the gyrokinetic code, GENE, to study the effect of lithium conditioning on pedestal instabilities and transport. Lithiated discharges have broader, ELM-free, pedestals. We investigate the roles of ETG, ITG/TEM, MTM, and KBM. A comprehensive study of their stability and proximity to threshold will be undertaken. Among other things, we will consider the particle transport in relation to the changes in particle sources produced by the lithium conditioning. With this analysis a fuller picture can be constructed of the effects of lithium coatings on pedestal transport, which may contribute to the development of optimized, ELM-free reactor scenarios.