Electron Transport in NSTX

The electron heat transport in NSTX is investigated. The inferred $\chi_e$'s from TRANSP were compared to those calculated from electron temperature gradient (ETG) theory [1] for a variety of discharges. Reasonable agreement was found for electrostatic and electromagnetic ETG theory with the $\chi_e$'s calculated for a 2 MW discharge in both the L- and H-phases. H-mode discharges at low toroidal field ($0.35$T) show good agreement with the electromagnetic ETG, while for discharges at $0.45$T and $0.55$T, the inferred $\chi_e$ agrees with the gyro-Bohm scaing of $T_e^{3/2}/B^2$. For these higher field discharges, GS2 calculations show the ETG to be stable, while it is unstable at $0.35$ T with a maximum growth rate at $k_\theta\rho_e \sim 0.3$. The heat flux obtained from the simulation of the ETG 3-field model [2] will be compared. And the effect of inverted profile $\nabla n_e\cdot\nabla T_e < 0 $ on the ETG electron transport will be discussed. \newline \newline [1] W. Horton {\it et. al.}, Phys.Plasmas \textbf{11}, 2600 (2004). \newline [2] W. Horton {\it et. al.}, Nuclear Fusion \textbf{45}, 976-985 (2005).