Community Research and Development Information Service - CORDIS

Abstract

Collective Thomson scattering, using a high-power pulsed D(2)O laser at 385 microns and a heterodyne receiver system, has provided local ion temperature (T(i)) measurements of the plasma in the TCA tokamak. Recent improvements in the noise-equivalent power of the Schottky barrier diode mixers made it possible to achieve a typical precision of +/-12% for a single shot measurement at densities above 1.0E20/m3. Even at densities of standard TCA discharges (5x1.0E19/m3) the uncertainty is better than +/-25%. For the interpretation of the measured spectra and the evaluation of T(i), the lcal value of the electron temperature (T(e)) is an important parameter. Therefore, T(e) was measured simultaneously by incoherent Thomson scattering at 0.694 microns during a series of shots. The density was obtained from a far-infrared interferometer. An independent measurement of T(i) on TCA can be obtained from a neutral particle analyser. Comparison of the results from the two methods showed good agreement. The precision of a T(i)-measurement depends strongly on the plasma density. Since an uncertainty of +/-25% at standard densities may still not be regarded as satisfactory, further investigations using a numerical simulation code have been carried out to find ways of improvement.

Additional information

Authors: SIEGRIST M, Centre de Recherches en Physique des Plasmas, Ecole Polytechnique Fédérale de Lausanne, Lausanne (CH);BEHN R ET AL., Centre de Recherches en Physique des Plasmas, Ecole Polytechnique Fédérale de Lausanne, Lausanne (CH);DICKEN D, Universität Düsseldorf, Institut für Laser- und Plasmaphysik (DE);HACKMANN J, Universität Düsseldorf, Institut für Laser- und Plasmaphysik (DE)
Bibliographic Reference: Report: LRP 406/90 EN (1990) 18 pp.
Availability: Available from Confédération Suisse, Centre de Recherches en Physique des Plasmas, Ecole Polytechnique Fédérale de Lausanne, 21 avenue des Bains, 1007 Lausanne (CH)
Record Number: 199011230 / Last updated on: 1994-12-01
Category: PUBLICATION
Original language: en
Available languages: en