Turbulence-driven Transport and Spreading at the Edge of DIII-D L and H-Mode Plasmas.

Turbulent radial particle flux, heat flux, electron intensity flux, and turbulence energy flux are measured at the edge of DIII-D in L0mode, during the transition from L to H-mode, and the resulting H-mode plasmas. The radial turbulent particle and energy fluxes are outward both inside and outside the LCFS, but the turbelence energy flux is negative inside the LCFS and outwar/positive in the SOL> All the fluxes are reduced during the transition to, and during H-mode. This work aims to test theories of turbulencespreadingthat mayresult in a mechanism to control the SOL width, i.e. the ehat flux footprint in tokamak plasmas.

The rms levels of density and electric field fluctuations decay monotonically with radius towards the SOL and there is a 8X reduction of fluctuations and fluxes magnitude in H-mode.

The change of direction measured in the turbulence energy flux is consistent with the region of inward-traveling holes, marked by negative skewnessm slightly inside the LCFS thus the energy flux is heavily influene by the holes, consistent with holes propagating radially inwards carrying colder plasma at lower density. The hole-blob dynamics has been understood as the result of interchange instabiities in the edge