Aachen PK 2003 – scientific programme

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P: Plasmaphysik

P 4: Poster I

P 4.48: Poster

Monday, March 17, 2003, 17:45–19:15, Foyer

Silane injection into the TEXTOR edge plasma and modelling of its local transport — •Waldemar Gralla, Andreas Kirschner, Peter Wienhold, and Volker Philipps — Institut für Plasmaphysik, Forschungszentrum Jülich GmbH, EURATOM Association, Trilateral Euregio Cluster, D-52425 Jülich, Germany

The understanding of the transport processes of impurities in the edge plasma of fusion machines is indispensable in order to predict the erosion and re-deposition behaviour of future machines such as ITER. In TEXTOR the transport of particles in the edge plasma can be investigated by means of limiter locks which are equipped with diagnostics such as spectroscopy for the two-dimensional observation of light emission. Deposition patterns can be analysed by post mortem ion beam techniques. Injection of silane molecules (SiH4) through a hole in a test-limiter exposed to the edge plasma of TEXTOR results in a very low local deposition efficiency (less than 1%) at the surface of the test-limiter. Modelling by means of the ERO-TEXTOR code aimed at the comparison of the emitted SiII light and the local deposition efficiency. While the modelled light emission showed reasonable agreement with the observed pattern the calculated deposition efficiency is in general much too high. Assuming zero sticking for silane radicals the modelled deposition efficiency is still about 6%. Possible reasons for this discrepancy will be discussed.