TURBULENT HEAT AND PARTICLE-FLUX RESPONSE TO ELECTRIC-FIELD SHEAR

Turbulent heat and particle fluxes are shown to have different respons es to ExB shear flow in edge plasmas. Recent work has shown that ExB s hear can affect the cross phase between electrostatic potential and pr essure fluctuations as well as fluctuation levels, thus affecting the heat and particle fluxes. Resistive pressure gradient driven turbulenc e (RPGDT) is considered including a collisional electron temperature e quation. While the particle flux is sensitive to moderate amounts of s hear in the radial electric field, the heat flux is insensitive to mod erate shear. In the collisional regime, the difference in the sensitiv ity of the heat and particle fluxes to ExB shear is due to the large p arallel heat conductivity. The large parallel heat conductivity domina tes the temperature response to electrostatic perturbations. In lower collisionality regimes, the difference in the dissipation rates betwee n density and temperature is negligible, but other effects can still p roduce different responses in the heat and particle fluxes. (C) 1998 A merican Institute of Physics.