Rm. Castro et al., TRANSPORT IN THE PLASMA EDGE OF A TOKAMAK WITH HIGH MHD ACTIVITY, Nuovo cimento della Societa italiana di fisica. D, Condensed matter,atomic, molecular and chemical physics, biophysics, 15(7), 1993, pp. 983-994
Electrostatic turbulence and various aspects of magnetic fluctuations
have been investigated, in the edge region of the TBR-1 tokamak, by us
ing a set of Langmuir and magnetic probes, and a triple probe. Measure
ments of plasma parameters such as plasma potential, density, temperat
ure and magnetic field were taken in order to elucidate the effect on
transport of the electrostatic and magnetic fluctuations in the edge.
The fluctuations levels are found to be higher than in most tokamaks.
The particle flux is outward and slightly higher than that calculated
from Bohm diffusion, and occurs in the frequency region typical of the
macroscopic MHD oscillations. The Mirnov-oscillation frequencies in T
BR-1 are higher than those observed in other tokamaks and, consequentl
y, there is an uncommon superposition between the Mirnov and turbulent
density fluctuations spectra. This fact and the presence of high MHD
activity may contribute to elucidate the possible influence of the mag
netic oscillations on the electrostatic transport observed in the plas
ma edge.