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Abstract

An argon injection experiment on FTU plasma has been used to investigate the physical mechanism responsible for impurity production. A simple 0-D model for the SOL, coupled with sputtering by the main deuteron flux and self-sputtering, can reproduce the variation of metallic impurity concentration, when argon is puffed into the plasma. The increase of radiation power losses leads to a decrease of the SOL temperature, and therefore to a decrease of the sputtering yield. Since Z(eff) remains essentially unchanged by Ar puffing, a fraction of high Z impurity is substituted by Ar ions. As a consequence both the line radiation emission profile and the total radiation losses are modified, while all the other plasma parameters (temperature and density profiles, ohmic power and energy confinement time) remain unchanged. Radiation losses increase up to 80 % of the input power, at relatively high densities, with a corresponding decrease of the heat load on the limiter surface.

Additional information

Authors: PIERONI L, ENEA, Centro Ricerche Energia Frascati, Roma (IT);CONDREA I, ENEA, Centro Ricerche Energia Frascati, Roma (IT);FRANZONI G, Politecnico di Torino, Dipartimento di Energetica (IT)
Bibliographic Reference: Report: RT/ERG/FUS/94/10 EN (1994) 18 pp.
Availability: Available from Servizio Studi e Documentazione, ENEA, Centro Ricerche Energia Frascati, C.P. 65-00044 Frascati, Roma (IT)
Record Number: 199510812 / Last updated on: 1995-07-17
Category: PUBLICATION
Original language: en
Available languages: en