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 phi(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 GAMMA(nphi) scales as n(e)B-2+/-1 in the edge plasma and as n(e)0B-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(theta)BAR varies approximately as the inverse ion Larmor radius rho(s)-1, with k(theta)rho(s)BAR congruent-to 0.04. Comparison is made with theoretical predictions.