EMPIRICAL TRANSPORT-COEFFICIENTS COMPARED WITH QUASI-LINEAR FLUCTUATION INDUCED TRANSPORT

Empirical scaling relations for the electron heat diffusivity χe, the diffusion coefficient D and the inward drift velocity vinin the Ohmic, L- and H-regimes of ASDEX are checked against anomalous transport predicted for electrostatic or magnetic fluctuations. It is stressed that χe and D exhibit the same dependence on the fluctuation spectrum, which explains the coupling of these diffusivities observed in all confinement regimes. Th ratios χe/D 3.3 and are shown to be general results of quasi-linear fluctuation induced transport and to agree with the empirical coefficients i the Ohmic, L- and H-regimes. Also discussed are the consequences of χe D for the interpretation of the saturated and improved Ohmic confinement, and of vin D for the density profile shape. © 1990 IOP Publishing Ltd.