Quasi-Steady Magnetic Field Generated by Pulse Forming Network for Magnetohydrodynamic Aerobraking

In this study, a quasi-steady pulsed magnetic field system combining a pulse forming network (PFN) and an air-core coil was developed for magnetohydrodynamic aerobraking experiments in an expansion tube. The system was developed to overcome limitations of permanent magnets in magnetic field strength and spatial distribution. The two models differed in curvature, and their magnetic field distributions were evaluated using the finite element magnetic analysis software FEMM. The system was applied to expansion-tube experiments, in which the magnetic field was synchronized with a shock wave propagating at [Formula: see text]. A pulsed current of approximately 1 kA generated a magnetic flux density of up to 1.5 T near the stagnation point, and the quasi-steady duration exceeded twice the effective test time. High-speed imaging showed that the thickness of the self-emission region increased by approximately 15.7% and 16.2% for the two models, respectively. The observed increases were consistent with theoretical predictions and trends reported in previous studies. Changes were also observed in the emission spectra measured inside the shock layer. The present results demonstrate that the developed system enables strong magnetic fields and flexible field distributions under short-duration expansion-tube conditions and provides an experimental approach for investigating MHD aerobraking.