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Abstract

The modification of power scrape-off-length, lq, and power deposition are studied during various configurations in ohmic Tore Supra plasmas. The plasma is either leaning on the horizontal limiter alone, on the full set of 6 pump limiters or on the inner bumper limiter in all configurations with and without the ergodic divertor system energised. From comparison of the infrared images of the limiter, the lq for power deposition was found to be slightly less than 9mm (+/-1mm) in ohmic plasma, in agreement with the predicted design value of 10mm. Inserting 6 limiters, instead of 1, does not modify lq significantly, but leads to small asymmetries. The power is shared by all the limiters and the maximum surface temperature on the horizontal limiter decreased. These values have been independently determined by calorimetric measurements made on the integrated energy deposition on the horizontal limiter and other internal structures 5cm into the scrape-off layer. These values agree with the infrared measurements in the two cases. In the presence of the ergodic divertor a broadening of the scrape-off layer is observed, the e-folding length for power deposition reaching 2.5cm. Large asymmetries on power deposition can be seen on the front face of the limiter, leading to the formation of hot spots at the leading edges.

Additional information

Authors: GUILHEM D, CEA, Département de Recherches sur la Fusion Contrôlée, Saint-Paul-lez-Durance (FR);CHATELIER M, CEA, Département de Recherches sur la Fusion Contrôlée, Saint-Paul-lez-Durance (FR);CHAPPUIS P ET AL., CEA, Département de Recherches sur la Fusion Contrôlée, Saint-Paul-lez-Durance (FR)
Bibliographic Reference: Paper presented: 9th International Conference on Plasma Surface Interactions, Bournemouth (GB), May 21-25, 1990
Availability: Available from (1) as Paper EN 35526 ORA
Record Number: 199011223 / Last updated on: 1994-12-01
Original language: en
Available languages: en