Spectroscopic characterisation of the PSI-2 plasma in the ionising and recombining state
Pospieszczyk, A. × Reinhart, M. Unterberg, Bernhard Brezinsek, Sebastijan Kreter, Arkadi Samm, Ulrich Sergienko, G. Schweer, B. Salmagne, C. Reiter, Detlev # Baelmans, Martine # Wünderlich, D. # Fantz, Ursel #
Journal of Nuclear Materials vol:438 issue:Supplement pages:1249-1252
In the linear plasma simulator PSI-2, capable of producing electron temperatures and densities of 1–20 eV and 1017–1019 m3 in the target region, a deuterium plasma with a simultaneous ionising and recombining region has been produced. The latter appeared when a sufficiently high extra deuterium gas flow was applied at the target region. An imaging spectrometer was used to measure Te and ne – profiles via the analysis of the Paschen-series resulting in drops down to 0.1 eV and 1018 m3 in the recombining region whereas intensity ratios of Ha, Hb and Hc provided ne in the ionising part. In the latter case ne was also deduced from the rotational temperature of the D2 molecules. Comparison with probe data yielded a reasonable agreement in that case. A detailed analysis of the atomic level populations and their light emissions provided some insight into the contribution of possible recombination mechanisms such as EIR and MAR.