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Abstract

The 2D-multifluid code EPIT has been used to study the problem of impurity production and transport in the ITER tokamak scrape-off layer (SOL). The model is based on Braginskii type fluid equations for background plasma and rate equations for impurity ions. An analytical model for neutrals is employed which takes into account recycling of hydrogen, sputtering and self-sputtering of impurity atoms at the target consistently with the edge plasma dynamics. Calculations have been performed for beryllium, carbon and nickel target plates under the assumption that physical sputtering is the only mechanism of impurity production. Results show that for the beryllium and carbon plates, the plate erosion is high. In the case of carbon plates, up to 45 % of the power flowing to the SOL can be radiated. For beryllium plates, impurity radiation is negligible. In the case of nickel, radiation is much stronger (up to 65 %) and, simultaneously, impurity production much lower, while the impurity retention in the SOL improves. A simple 1D analytical model of the SOL is proposed in order to determine the dependence of the plasma parameters at the plate on the input energy, particle fluxes and the hydrogen recycling. A comparison between model predictions and code results is presented.

Additional information

Authors: ZAGORSKI R, ENEA, Centro Ricerche Energia Frascati, Roma (IT)
Bibliographic Reference: Report: RT/ERG/FUS/94/25 EN (1995) 19 pp.
Availability: Available from Servizio Studi e Documentazione, ENEA, Centro Ricerche Energia Frascati, C.P. 65-00044 Frascati, Roma (IT)
Record Number: 199510564 / Last updated on: 1995-04-21
Category: PUBLICATION
Original language: en
Available languages: en