Measurements of correlations between thermal and particle transport in JET

Radial thermal and particle diffusivities have been measured by using transient methods yielding χ and D simultaneously in the plasma interior at 0.5 < or approx. r/a < or approx. 0.7. Values of χe = 2.9 ± 0.4 m2·s-1 and De = 0.4 ± 0.1 m2·s-1 have been measured in OH plasmas, giving χe/De = 7.2 ± 3. NBI heated H-mode plasmas are indistinguishable from OH plasmas in respect of χe, De and χe/De in the region specified. The ion thermal diffusivity has also been measured in H-mode plasmas, giving 1 < χi (m2·s-1) < 3, simultaneously with χe = 3 ± 0.5 m2·s-1, thus 0.3 ≤ χi/χe < 1. The large value of χe/De would suggest that micro-magnetic stochasticity, rather than E-tilde x B-vector convection, may be the key mechanism in anomalous thermal transport. (author). 19 refs, 5 figs, 1 tab