Studies of energy and particle transport in JET

Investigation on H-mode transport has concentrated on pulses where elevated confinement can be achieved. At the time of the L-H transition a prompt transport reduction in the core (as well as at the edge) of the discharge is observed. Poorly performing, higher Zeff discharges appear to have substantially the same core transport as record achieving pulses. New H-mode power threshold data were acquired in 1994, with ion B drift of both signs, confirming Pth to increase with Bt and ne. The transport of injected impurities indicates that, in L-mode discharges, the outer region of strong anomalous transport more or less coincides with the region of high shear (s > 1/2). Analysis of inward propagation of cold pulses supports the hypothesis that, when the edge temperature is perturbed, transport across the discharge suffers a prompt modification. (author). 20 refs, 6 figs