Simultaneous Measurements of Electron Thermal and Particle Transport in JET

An important objective in tokamak research is to find suitable descriptions for the measured thermal and particle fluxes, and to identify the underlying mechanism of transport. Many detailed models for transport in tokamaks have been developed, which make specific predictions for the correlations between the thermal and particle transport coefficients. In order to exclude some of the contending models, accurate measurements of the correlations are required. In order to reduce uncertainties arising from shot-to-shot and spatial variations it is necessary to determine these coefficients simultaneously in the same spatial region of the plasma. In this paper we describe evaluation of electron thermal and particle transport coefficients by three different methods satisfying the above requirements: (a) analysis of inward propagation of electron temperature and density perturbations produced when a small pellet is injected into the plasma; (b) measurements of the velocity and damping of electron temperature and density pulses propagating outwards following sawtooth collapse; (c) time dependent transport analysis applied to non-stationary plasmas.
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JETP88050 441.28 Kb