Scaling of far edge plasma turbulence and fluctuation induced particle transport in the TEXT tokamak

Scaling studies of turbulence and turbulence induced particle transport have been performed in the edge plasma of the TEXT tokamak using Langmuir probes and a fast probe drive. Emphasis was placed on examining possible free energy sources, such as the local density and temperature gradients. To first order, the fluctuation levels n e /n e and ϕ f /T e are not linear functions of either the electron density or electron temperature gradient drives alone. The density fluctuation level n e /n e scales approximately as B -1 , while the fluctuation induced particle flux Γ nϕ scales as n e B -2±1 in the edge plasma and as n e 0 B -2±1 in the scrape-off layer. Here, B and n e are the magnetic field and the local density, respectively. The mean poloidal wavenumber k θ varies approximately as the inverse ion Larmor radius ρ s -1 , with k θ ρ s ≈ 0.04. Comparison is made with theoretical predictions