Thomson scattering diagnostic on FTU tokamak : Calibration, operation and first results
The FTU Thomson scattering system is employed for the measurement of electron temperature and density spatial profiles in tokamaks. The radiation source is a Nd:YLF laser at 1053 nm, divergence 0.4 mrad full angle, capable of delivering a burst of 10 pulses with energies of 4.5 J/pulse; the interpulse time can be regulated from 20 ms to 100 ms. The scattered radiation is collected by two objectives: the first looks at the plasma centre, the second at the plasma edge. Bundles of optical fibres in the focal plane of the objectives carry the scattered light from the tokamak hall to a set of 19 interference filter polychromators, whose transmission is 70 % and the rejection of the stray light at the laser wavelength is 1.0 E-7. The spectral calibration of the polychromators is presented. The absolute calibration of the scattering system for the electron density measurement was carried out by Raman scattering on hydrogen and deuterium. The results of the temporal evolution of T(e) and n(e) spatial profiles are presented for ohmic plasma heating and for lower hybrid current drive.
Bibliographic Reference: Article: 35th Annual Meeting of the American Physical Society (1993) pp. 1-19
Record Number: 199311561 / Last updated on: 1994-11-28
Original language: en
Available languages: en