Remote measurement method for current pulses and magnetic flux density

The paper presents a non-contact method for measuring high-amplitude current pulses and magnetic flux density, with potential applications in military technology, biomedicine, and electrical power engineering. The proposed approach introduces a self-referenced reconstruction of the discharge current, which compensates for the probe's spatial placement. While the local magnetic flux density B probe ( t ) is measured at the probe position via Faraday induction, the main discharge current i 1 (t) is reconstructed from the relationship between the probe voltage u probe (t) and the excitation-coil voltage u 1 (t), making the reconstructed current waveform effectively independent of the probe's precise position. Consequently, the magnetic flux density at a defined location, such as the coil centre, can be calculated from the reconstructed current and the known excitation-coil geometry. The validity of the method was verified both experimentally and numerically using the Finite Element Method (FEM) within the CST Studio Suite environment. In the experimental setup, the magnetic pulse was generated by discharging a capacitor bank ( C = 15 mF) through an air-core excitation coil ( L 1 = 44.3 μH) via a thyristor switch. At an initial voltage of 350 V, a peak current of i max = 2642 A and a maximum magnetic flux density of B max = 7.14 T were achieved, with a pulse width of Δ t = 2.5 ms. Energy balance analysis revealed that of the initial 919 J stored in the electric field, approximately 51% (473 J) was dissipated as thermal losses in the winding resistance, while the remaining 446 J was radiated into the environment as an electromagnetic pulse. The maximum instantaneous power delivered by the capacitor reached 342 kW, and the volumetric magnetic field energy density at the coil's centre reached 20.3 MJ·m −3 . Spectral analysis indicates that the dominant harmonic components of the pulse are concentrated within the 100 Hz to 150 Hz frequency range.