On measuring the electron heat diffusion coefficient in atokamak from sawtooth oscillation observations

Abstract

A number of new methods are discussed for determining the electron heat conduction coefficient χe in a tokamak from the experimental observation of the space-time evolution of the temperature perturbations induced by internal disruptions. In the Oak Ridge Tokamak (ORMAK) the various average values of χe and the radial dependence of χe are found to be consistent with and more precise than the χe(r) determined by conventionally analysing the electron power balance equation. The net result of these measurements is to conclusively prove that the dominant radial electron heat transport mechanism in tokamaks is a microscopic, diffusive process.