Boundary plasma energy transport in JET ELMy H-modes

Power deposition profiles on JET MkIIGB divertor plates were measured for a variety of plasma conditions. Comparison of experimental measurements with theoretical predictions of two dozen candidate models of perpendicular heat conductivity suggests that a combination of classical ion conduction and ion orbit loss from the pedestal region dominates radial energy transport in the scrape-off layer (SOL), at least in the vicinity of the separatrix, during the inter-edge localized mode (ELM) phase of H-mode discharges. Although not a conclusive proof of suppression of (ion) turbulence, it is consistent with the hypothesis that the edge transport barrier extends into the SOL during the inter-ELM phase. Extrapolations to ITER predict an outer target power width of 3 +/- 1 mm-omp (mapped to the outer mid-plane) at the entrance into the divertor volume.