Magnetic Field Testing Technique of System-Generated Electromagnetic Pulse Based on Magnetoresistance Effects

Abstract

To address the technical challenges of system-generated electromagnetic pulse (SGEMP) measurement, the generation environment of SGEMP is introduced, and the characteristics of the magnetic field waveform to be measured are analyzed first in this paper. Then a magnetoresistance-based SGEMP measurement method is proposed for the first time. Aiming at the problem that the high frequency response of the existing commercial magnetoresistance chips cannot meet the test requirements, a pulsed magnetic field detector with strong anti-interference ability is developed in this work based on the tunneling magnetoresistance (TMR) sensor chip developed by Lanzhou University and a high-gain amplifier circuit with common mode rejection and a good shielding structure. It can be shown from the calibration results that the detector sensitivity factor is 4.0 nT/mV and the measurable pulse front is greater than or equal to 28 ns, which meet the requirements of SGEMP magnetic field waveform measurement. Based on the developed detector, the ideal test waveform is obtained under the “Flash II” hard X-ray pulse source through a reasonable experimental design. The related work has laid a foundation for validating the numerical calculation model and further mastering the propagation law and effect mechanism of SGEMP.