Production and Measurement of Megagauss Magnetic Fields in Single-Turn Coils

Abstract

In the report, diagnostic apparatus is described developed for measurement of pulsed magnetic fields in the megagauss range. The measurement technique is based on the Faraday effect (rotation of the polarization plane). Some papers [1,2] refer to the use of such a method. In our experiments, dense flint (Tø-5) specimens with a relatively high value of the Verdet constant served as an active medium in which the rotation of the light polarization plane occured. A gas laser was used as a source of the monochromatic linearly-polarized light. The method of calibration and determination of the Verdet constant for the glass types used is described, the accuracy and sensitivity of measurements is evaluated. The comparison is carried out with a generally-used probe technique of magnetic field measurement.

Megagauss magnetic fields were produced in single-turn coils in small volumes ~ 0.1 cm³. A low-inductance capacitor bank (capacity 120 µF, peak voltage 30 kV) served as a current generator. The maximum rate of the current rise achieved 10¹² A/s. The measurements of the high pulsed magnetic fields in various-shaped coils were performed with the purpose to evaluate the relative role of mechanisms leading to the coil destruction.