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A collective laser light scattering experiment using a CO(2) laser beam to measure plasma density fluctuations in the Tore Supra tokamak has been realised. This paper describes in detail the optical setup, signal processing, acquisition and control systems required for this experiment. As the density fluctuations propagating in tokamaks have small wave numbers and require small scattering angles, such scattering experiments are considered to have no resolution along the beam. However, taking advantage of the pitch angle variation of the magnetic field lines around the magnetic axis along a vertical chord, it has been possible to obtain partial spatial localisation of the scattering volume by rotating the direction of the analysed wave vector in a horizontal plane. Heterodyne detection is used to determine the propagation direction of the fluctuations. The experiment has been tested on acoustic waves, and the first results obtained on Tore Supra show the existence of a spatial resolution.

Additional information

Authors: TRUC A ET AL., Ecole Polytechnique de Palaiseau, Laboratoire de Physique des Milieux Ionisés (FR);LAVIRON C ET AL., CEA, Departement de Recherches sur la Fusion Contrôlée, CEN Cadarache, Saint-Paul-lez-Durance (FR)
Bibliographic Reference: Report: EUR-CEA-FC-1437 EN (1991) 27 pp.
Availability: Available from CEA, Département de Recherches sur la Fusion Contrôlée, Saint-Paul-lez-Durance (FR)
Record Number: 199111652 / Last updated on: 1994-12-02
Original language: en
Available languages: en