Thermal transport analysis of the edge region in the low and high confinement stages of a DIII-D discharge

The ion and electron thermal diffusivities have been inferred from measured density and temperature profiles in the edge of a DIII-D [J. Luxon, Nucl. Fusion 42, 614 (2002)] discharge with a low confinement (L-mode) stage followed by a high confinement (H-mode) stage free of edge localized modes. Conductive heat flux profiles used to construct the inferred thermal diffusivities were calculated taking into account heat convection, radiation, atomic physics effects of recycling neutrals, ion-electron equilibration, and neutral beam heating. The inferred thermal diffusivities were compared with theoretical predictions. (c) 2007 American Institute of Physics.