ELECTRON TEMPERATURE FLUCTUATIONS AND CROSS-FIELD HEAT TRANSPORT IN THE EDGE OF DIII-D

OAK-B135 The fluctuating E x B velocity due to electrostatic turbulence is widely accepted as a major contributor to the anomalous cross-field transport of particles and heat in the tokamak edge and scrape-off layer (SOL) plasmas. This has been confirmed by direct measurements of the turbulent E x B transport in a number of experiments. Correlated fluctuations of the plasma radial velocity v{sub r}, density n, and temperature T{sub e} result in time-average fluxes of particles and heat given by (for electrons): Equation 1--{Lambda}{sub r}{sup ES} = <n{tilde v}{sub r}> = 1/B{sub {var_phi}}<{tilde n}{tilde E}{sub {theta}}; Equation 2--Q{sub r}{sup ES} = <n T{sub e} {tilde v}{sub r}> {approx} 3/2 kT{sub e}{Lambda}{sub r}{sup ES} + 3 n{sub e}/2 B{sub {var_phi}} <k{tilde T}{sub e}{tilde E}{sub {theta}}> = Q{sub conv} + Q{sub cond}. The first term in Equation 2 is referred to as convective and the second term as conductive heat flux. Experimental determination of fluxes given by Equations 1 and 2 requires simultaneous measurements of the density, temperature and poloidal electric field fluctuations with high spatial and temporal resolution. Langmuir probes provide most readily available (if not the only) tool for such measurements. However, fast measurements of electron temperature using probes are non-trivial and are not always performed. Thus, the contribution of the T{sub e} fluctuations to the turbulent fluxes is usually neglected. Here they report results of the studies of T{sub e} fluctuations and their effect on the cross-field transport in the SOL of DIII-D