ION TEMPERATURE-GRADIENT DRIVEN TURBULENCE IN THE WEAK DENSITY GRADIENT LIMIT

The anomalous heat transport arising from the ion temperature gradient driven mode or ηi-mode turbulence is extended to the range of the weak density gradient limit (ηi = Ln/ L T→ ∞ ), which is appropriate for H-mode dishcarges. It is shown that the anomalous ion heat conductivity χi with L n→ ∞ scales as χi = g(ρs/ LT) (cTi/eB) exp( - βσ) with σ = (T e/Ti) (LT/Ls), β≃4, and g≃1. This χi scaling is the natural extension for high ηi of the scaling of χi for K = (T i/Te) (1 + ηi) ≲ 4 obtained [Phys. Fluids B 2, 1833 (1990)] from analytical and numerical studies. © 1990 American Institute of Physics.