Development of a Magnetooptic Current Measurement System for High, Pulsed Currents

摘要

A current-measurement system based on the Faraday rotation in a single-mode fiber for a screw pinch experiment is described. It is shown that an ultra low birefringence spun single-mode fiber is extremely suitable for use in a magneto-optic current-meter. The properties of this fiber were investigated. Measurements of high, pulsed currents (Imax = 1 MA: f = 25 kHz) with good accuracy and in accord with theory are presented. In order to calculate the current unambiguously and more accurately from the signals of the current-meter, a system with a double detector (to measure sin2 phi and cos2 phi simultaneously) was constructed. Measurements of high, pulsed currents with this system are also presented. It is concluded that a beam splitter prism is not the correct instrument for double detector measurements. A 50% transparant mirror and a double lens are suggested.