Turbulent heat and particle flux response to electric field shear

Abstract

Turbulent heat and particle fluxes are shown to have different responses to E×B shear flow in edge plasmas. Recent work has shown that E×B shear can affect the cross phase between electrostatic potential and pressure fluctuations as well as fluctuation levels, thus affecting the heat and particle fluxes. Resistive pressure gradient driven turbulence (RPGDT) is considered including a collisional electron temperature equation. While the particle flux is sensitive to moderate amounts of shear in the radial electric field, the heat flux is insensitive to moderate shear. In the collisional regime, the difference in the sensitivity of the heat and particle fluxes to E×B shear is due to the large parallel heat conductivity. The large parallel heat conductivity dominates the temperature response to electrostatic perturbations. In lower collisionality regimes, the difference in the dissipation rates between density and temperature is negligible, but other effects can still produce different responses in the heat and particle fluxes.