Berlin 2001 – scientific programme
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P: Plasmaphysik
P 8: Magnetic Confinement and Plasma Technology (Poster Session)
P 8.11: Poster
Monday, April 2, 2001, 12:30–15:00, AT2
Measurements of impurity density profiles using a diagnostic hydrogen beam in TEXTOR-94 — •A. Kreter1, R. Jaspers2, B. Schweer1, and B. Unterberg1 — 1Institut für Plasmaphysik, Forschungszentrum Jülich GmbH, EURATOM Association, 52428 Jülich, Germany* — 2FOM Instituut voor Plasmafysica, EURATOM Association, Postbus 1207, 3430 BE Nieuwegein, The Netherlands*
Measurements of the impurity density profiles in TEXTOR-94 were performed by means of Charge-eXchange Recombination Spectroscopy (CXRS) using the diagnostic hydrogen beam RUDI. RUDI is based on a rf-discharge ion source and provides an equivalent neutral current of 1 A with an extracting voltage of 50 keV, an angular divergence of ± 0.5∘ and a pulse duration of 4 s, modulated with 500 Hz.
The density profiles of C6+, C5+, Ne10+, Ne9+, Ne8+ and O8+ were measured in discharges with pure ohmic and additional heating. The accuracy of the measurements is mainly determined by the accuracy of the CX-rate coefficients and amounts to 30-40 % for the fully ionized impurity ions. The influence of the excited beam particles on the CX-signals was taken into account.
The measured impurity densities were compared with
calculations of the selfconsistent 1D impurity
transport code RITM. There is a good qualitative
agreement between the radial shapes of the measured and
calculated impurity density profiles. Quantitatively
there are discrepancies of up to 50 %, which in the
case of the not fully ionized particles can be partly
explained by uncertainties in CX-rate coefficients.
*Partners in the Trilateral Euregio Cluster