Doppler backscattering system for measuring fluctuations and their perpendicular velocity on Tore Supra
- Laboratoire de Physique et Technologie des Plasmas, CNRS-Ecole Polytechnique, 91128 Palaiseau cedex (France)
Backscattering of a microwave beam launched in oblique incidence makes possible measurement of density fluctuations close to the cut-off with a selected wave number k-vector{sub perpendicular}=-2k-vector{sub i}, where k-vector{sub i} is the beam wave vector at the reflection layer. On the system installed on Tore Supra, the incidence of the Gaussian beam is controlled thanks to a tiltable monostatic antenna. The microwave part of the system is based on a fluctuation reflectometer scheme with heterodyne detection, and the choice of a V band (50-75 GHz) microwave source and O mode polarization is appropriate for typical enhanced plasma regimes (n{sub 0}=3-7x10{sup 19} m{sup -3}). Both the scattering wave number k{sub perpendicular} and the scattering localization r/a can be changed during a shot, owing to the steppable probing frequency and the motorized antenna (tilt angle 0-10 deg.). The wave-number range k{sub perpendicular} is 4-15 cm{sup -1}, with a wave-number resolution around 2 cm{sup -1}, and the localization r/a{approx}0.3-0.85. The Doppler effect also provides the perpendicular velocity profile for the same position range. Experiments confirm the diagnostic capabilities.
- OSTI ID:
- 20641181
- Journal Information:
- Review of Scientific Instruments, Vol. 75, Issue 10; Other Information: DOI: 10.1063/1.1787920; (c) 2004 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0034-6748
- Country of Publication:
- United States
- Language:
- English
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