Fiber—optic sensor for plasma current diagnostics in tokamaks

A simple fiber-optic sensor (FOS) based on Faraday effect in an isotropic single-mode fiber (SMF) was developed for discharge current diagnostics in tokamaks.. Current resolution of 30 Ampere/turn and temporal resolution of ~1ms have been obtained in the hostile electromagnetic and radiation environment of an operating tokamak. These resolution values were stipulated by quasi-isotropic SMF and differential photoreceiver shot—noise limited outputThe first experiments with the FOS application for plasma current measurements in tokamak FT-1 are discussed.