Community Research and Development Information Service - CORDIS


On the JET facility, the line-integrated electron density is measured by a multi-channel far-infrared (FIR) interferometer. The basic source of radiation is a deuterium cyanide laser (15195mm) measuring the density along four vertical and four nearly horizontal (lateral) channels. During high-density discharges the system suffers from fringe jumps that are manually partially corrected by an off-line program. This intermittent phenomenon prevents reliable usage of the measured line-integrated density in a real-time feedback controller. To solve this problem we have developed a method to correct the fringe jumps on the lateral channels in real time. The method uses the additional methyl alcohol laser (15118.8mm) interferometer present on the lateral channels to compensate the vibrations. The method has been successfully tested with off-line test data, before implementation on a VERSA Module Eurocard system for the real-time control of the JET discharges.

Additional information

Authors: MAZON D, Association Euratom-CEA sur la Fusion, CEA Cadarache, Saint-Paul-lez-Durance (FR);JOFFRIN E, Associazione Euratom-ENEA sulla Fusione, C.R. Frascati, Frascati (IT);INNOCENTE P, Associazione Euratom�ENEA sulla Fusione, Consorzio RFX, Padova (IT)
Bibliographic Reference: An article published in:Review of Scientific Instruments, vol.74 no.8 (2003) pp.3645-3652
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