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A possible explanation for differences in the behavior of multi-faceted asymmetric radiation from the edge (MARFE) in normal and reversed toroidal field configurations, based on the influence of poloidal E×B drift, is offered. The poloidal E×B drift creates poloidal rotation that tends to shift the MARFE away from its stable position near the inner midplane. For a neoclassical radial electric field (Er≡−dΦ/dr

In the scrape-off layer of the Joint European Torus [P.-H. Rebut, R. J. Bickerton, and B. E. Keen, Nucl. Fusion 25, 1011 (1985)], Langmuir probes were used to measure the correlation of ion saturation current fluctuations parallel to the magnetic-field B. It was possible to realize three different probe tip separations (connection lengths) ∥B under almost identical plasma conditions and magnetic configuration. Among these, a probe tip separation of 66 m ∥B represents the largest value ever realized for this type of experiment. It was found that the correlation is reduced from ⩾80% at 0.75 m probe tip separation ∥B in the divertor to ≈40% at 23 m, but remains at ≈40% even for the 66 m separation. An upper limit for the ratio between the average wave numbers parallel and perpendicular to the magnetic field |k∥/k⊥

Frequency spectra of fluctuations for the ion saturation current, floating potential, and turbulent transport measured in the plasma edge of plasma confinement experiments (tokamaks and stellarators) have been analyzed to identify the frequency ranges characterized by a power dependence. Three main regions can be identified. For the intermediate frequency region, the decay of the spectra is close to 1/f, as is expected in self-organized criticality systems. This region is particularly important for the role that it plays in plasma transport and the self-similarity of the fluctuations and fluxes. The effect of plasma rotation on the decay indices has also been studied.

Three models for nonlocal electron thermal transport are here compared against Vlasov-Fokker-Planck (VFP) codes to assess their accuracy in situations relevant to both inertial fusion hohlraums and tokamak scrape-off layers. The models tested are (i) a moment-based approach using an eigenvector integral closure (EIC) originally developed by Ji, Held and Sovinec; (ii) the non-Fourier Landau-fluid (NFLF) model of Dimits, Joseph and Umansky; and (iii) Schurtz, Nicola\"i and Busquet's multigroup diffusion model (SNB). We find that while the EIC and NFLF models accurately predict the damping rate of a small-amplitude temperature perturbation (within 10% at moderate collisionalities), they overestimate the peak heat flow by as much as 35% and do not predict preheat in the more relevant case where there is a large temperature difference. The SNB model, however, agrees better with VFP results for the latter problem if care is taken with the definition of the mean free path. Additionally, we present for the first time a comparison of the SNB model against a VFP code for a hohlraum-relevant problem with inhomogeneous ionisation and show that the model overestimates the heat flow in the helium gas-fill by a factor of ~2 despite predicting the peak heat flux to within 16%., Comment: 15 pages, 8 figures. This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. The following article appeared in Brodrick et al., Physics of Plasmas 24, 092309 (2017) and may be found at http://dx.doi.org/10.1063/1.5001079