Measuring the electron heat diffusion coefficient in a tokamak from Sawtooth oscillation observations

A number of new methods are discussed for determining the electron heat conduction coefficient chi/sub e/ 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 chi/sub e/ and the radial dependence of chi/sub e/ are found to be consistent with and more precise than the chi/sub e/ (r) determined by conventionally analyzing 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