Investigation of CAE/GAE-induced electron thermal transport for NSTX-U

High values of core electron thermal transport (several 10's m$^2$/s) resulting in flat core temperature profiles in high power H-mode spherical tokamak plasmas remain unexplained. One hypothesis is high frequency fast ion modes GAE/CAEs driven by strong, super-Alfv\'{e}nic neutral beam heating can increase electron thermal transport in the core and cause the observed high $\chi _{e}$ [D. Stutman, \textit{et al.}, Phys. Rev. Lett., \textbf{102}, 115002 ( 2009)]. Additional work using ORBIT modeling and ad-hoc models of the fast ion modes demonstrates that the interaction of multiple modes with different m/n numbers at a single location can induce stochastic transport of the electrons, and can also exhibit a strong scaling of transport with mode amplitude [N.N. Gorelenkov, \textit{et al.}, Nucl. Fusion, \textbf{50}, 084012 (2010)]. This modeling work is extended to include measured mode structure, and modes located at multiple radial locations, as observed in experimental discharges, to improve the comparison to measured $\chi _{e}$, and also extended to NSTX-U parameters and plasma conditions to predict core electron thermal transport in the upgraded device.