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Abstract: On the limiter of Tore Supra, the heat loads map computed from deconvolution of IR surface temperatures shows good agreement with calorimetry measurements. This experimental heat pattern allows deducing the heat fluxes in the scrape-off layer using a 3D magnetic calculation and assuming only parallel heat transport along field lines. This calculation leads to an underestimation of the power circulating in the edge plasma according to the power balance, similarly to RFA measurements. The comparison between experimental heat loads on the limiter and modelling also shows a spreading of heat fluxes near the LCFS that cannot be explained only by parallel transport in the SOL. [Copyright &y& Elsevier]

Abstract: The precursors and following sequential events leading to radiative disruptions in Tore Supra have been analysed using infrared imaging, together with visible and ultraviolet spectroscopy of impurity species. A common feature observed prior to the disruptions is the appearance of a small (∼cm2) hot spot on the main plasma facing component, the Toroidal Pumped Limiter (TPL), clearly localised in a zone of thick carbon re-deposition (>100μm). A MARFE (Multifaceted Asymmetric Radiation From the Edge) is often triggered, followed by disruption. Such hot spots have been observed in ∼24% of the analysed disruptions, which is consistent with the fact that only 4/18 (22%) of the total area of the TPL is monitored with infrared cameras. These results suggest that over-heating of thick carbon re-deposition layers may play a role in the operational limits (MARFE, disruption) encountered. [Copyright &y& Elsevier]

Abstract: The new CIEL (Composantes Internes Et Limiteur) configuration of the Tore Supra tokamak has as its main plasma-facing component (PFC) a Toroidal Pumped Limiter (TPL) [P. Garin et al., in: Proceedings of the 20th Symposium on Fusion Technology, Marseille, vol. 2, 1998, p. 1709], which must sustain the bulk of the energy leaving the plasma. Analysis of the heat deposition pattern on the TPL indicates that perpendicular heat transport may play at least as significant a role as parallel heat transport [F. Saint-Laurent et al., Nucl. Fusion 40 (2000) 1047, R. Mitteau et al., these Proceedings]. We present a new approach for modelling the heat deposited onto the TPL, which follows test ‘heat packet’ trajectories backwards from the TPL towards the hot plasma column. Results are compared with experimental data and trends due to plasma parameters dependencies are described. Because of ripple effects, the limiter is covered by wetted areas with long connection lengths (tens of meters), and shadowed areas with very short connection lengths (centimeters). Sharp transitions between the two are clearly seen in experiment and also reproduced in the model. [Copyright &y& Elsevier]