Numerical and experimental study on the regulation of plasma by traveling magnetic field

To mitigate communication blackouts during hypersonic aircraft re-entry, a novel approach is proposed that utilizes a traveling magnetic field (TMF) to generate self-induced current. The principle of this method is that a TMF excites induced current in the plasma, which then interacts with the spatially and temporally varying magnetic field to generate electromagnetic forces, thereby regulating the distribution of local plasma. This paper describes an experiment performed to verify this theory. Numerical simulations were performed to model and analyze the local electron density distribution in the plasma. The results show that (i) the TMF’s velocity is a critical factor influencing the electromagnetic force and induced current density in the plasma, (ii) at a field strength of 0.15 T and a velocity approaching 9200 m s⁻¹, the peak electron density was reduced from n_e0 = 1.4×10¹² cm⁻³ to 2.1×10¹⁰ cm⁻³, and (iii) below critical densities for communication interruption, this reduction potentially avoids blackouts in the L-, S-, C-, and X-bands at an altitude of 40 km when the reduction ratio is less than 0.1. Experimental results indicate that applying a high-speed TMF significantly affects the electron density distribution in the plasma. The consistency between experimental and simulation results validates the effectiveness of the simulation approach. This verification suggests that our TMF method based on induced currents offers a promising new approach to addressing the limitations of the magnetic window method for mitigating communication blackouts during re-entry.