PPPS-2013: Magnetic field probe calibration at relevant field magnitude and frequency

Summary form only given. Magnetic field probes are invaluable diagnostics for pulsed inductive plasmoid devices where field magnitudes on the order of several kG are common.¹ The most common method of calibrating magnetic field probes is to use a Helmholtz coil to generate a large region of uniform magnetic field.^2,3 Difficulty driving large currents through an inductive load at high frequency typically results in field magnitudes of a few Gauss or less. The calibration factor is then necessarily assumed linear, even though the magnetic field of the primary experiment is several orders of magnitude larger than the field magnitudes used to calibrate the probe.^2,4,5 Calibration factors of two differential configuration magnetic field probes are presented as functions of frequency and field magnitude. Calibration values are determined experimentally using a 7.74 cm radius Helmholtz coil in three separate configurations. A broadband frequency sweep is performed with a network analyzer for frequency domain measurements while a function generator provides time domain measurements. These methods produce calibration factors over a large frequency range (100 kHz-1 MHz) with field magnitudes less than one Gauss. Large field magnitudes are achieved with a pulsed-power setup using multiple capacitor banks charged from 13-25 kV producing magnetic fields of at least 0.1 kG up to 3.8 kG. Tests are conducted at five frequencies in the range of interest. The calibration factors are calculated and presented as a function of field magnitude and frequency.