Heat flux pattern on the toroidal pump limiter of Tore Supra:: first observations and preliminary analysis

Tore Supra has re-started operation in 2001 with a partial toroidal pump limiter as the main plasma facing component. Assembled with actively cooled high heat flux elements, it has the shape of a toroidal ring. Thermal equilibrium is achieved within 4 s and the stabilised surface temperature is comparable to the design calculation. The observed heat flux pattern is similar to calculations realised beforehand with the heat deposition code TOKAFLU, and is dominated by the large toroidal field ripple. The power deposition is a combination of parallel convection and cross-field transport of similar magnitudes. The heat flux decay length is evaluated by three independent diagnostics to 10 mm. The excellent agreement between experiment and modelling indicates that the description of the power deposition mechanism is reasonable, although parameters such as the heat flux decay length and fraction of perpendicular power are still difficult to predict. (C) 2003 Elsevier Science B.V. All rights reserved.