Precise Measurement of a Magnetic Field Generated by the Electromagnetic Flux Compression Technique

TL;DR

This study evaluates the accuracy of magnetic field measurements in ultra-high fields up to 700 T, highlighting the limitations of pickup coils and the effectiveness of Faraday rotation for precise calibration.

Contribution

It introduces a calibration method using Faraday rotation to correct pickup coil measurements in ultra-high magnetic fields.

Findings

Pickup coil signals require correction for high-frequency response.

Faraday rotation provides reliable measurements near peak fields.

Pickup coils become unreliable at the highest magnetic fields.

Abstract

The precision of the values of a magnetic field generated by electromagnetic flux compression was investigated in ultra-high magnetic fields of up to 700 T. In an attempt to calibrate the magnetic field measured by pickup coils, precise Faraday rotation (FR) measurements were conducted on optical (quartz and crown) glasses. A discernible "turn-around" phenomenon was observed in the FR signal as well as the pickup coils before the end of a liner implosion. We found that the magnetic field measured by pickup coils should be corrected by taking into account the high-frequency response of the signal transmission line. Near the peak magnetic field, however, the pickup coils failed to provide reliable values, leaving the FR measurement as the only method to precisely measure an extremely high magnetic fields.