Thermal behaviour of deposited carbon layers on the Tore Supra Neutraliser
The temperature measured on the surface of the neutralisers of Tore Supra, which are the target plates under the toroidal pump limiter, that channel the particles into the pumping ducts, is significantly higher than expected because of thick carbon deposits forming on them. With growing deposits their temperature and cooling time constants increase. LHCD heating and gas puffing seem to enhance the growth. The deposits form at first isolated hillocks giving rise to spectral deformations in the near infra red range. Later on, they may form continuous films with black body like spectra to end up flaking off, again creating distorted spectra. The thermal behaviour of the thick continuous films can be described by a radiative model. The conducted power to the neutralisers for which this model is in accordance with the measurements is of the order of 0.1MW in ohmic discharges, which requires characteristic SOL decay-lengths of 7 to 8mm as deep as 5cm in the SOL. The thermal diffusivities deduced with this model from observations in Tore Supra and from laboratory experiments both show values 2 to 3 orders below the values of CFC.
Bibliographic Reference: An oral report given at: 10th International Workshop on Carbon Materials for Fusion Application, 16 September 2003
Availability: Available from Association EURATOM-CEA, Département de Recherches sur la Fusion Contrôlée, CEA Cadarache, F-13108 St Paul-Lez-Durance, France Tel: (+33) 4 42 25 70 01; Fax: (+33) 4 42 25 64 21 E-mail: email@example.com
Record Number: 200316830 / Last updated on: 2003-10-08
Original language: en
Available languages: en