Investigation of Divertor Heat Flux Width in \hbox{DIII-D} for 2010 Joint Research Target*

The 2010 Joint Research Target for NSTX, C-Mod, and DIII-D aims to improve prediction of divertor heat flux profile width for future divertors. In DIII-D we varied input power, toroidal field, plasma current $I_p$, and density. Divertor heat flux was obtained using IR thermography. We find that $w_{q,div}$ is most sensitive to $I_p$. Mapped to the outer midplane $w_{q,div}$ scaled like $w_{q,mid}$~(mm)~= 5.38/$I_p^{1.24}$~(MA). Scrape-off layer and pedestal density and temperature fluctuations were measured using midplane and x-point plunging Langmuir probes at the lower powers. From midplane fluctuation data, we obtained energy transport measurements, which we compare with transport coefficients obtained from onion-skin modeling using density profiles, and with experimentally determined heat flux widths in the divertor.