Spatial evolution characteristics and mechanism analysis of induced magnetic fields in an applied field magnetoplasmadynamic discharge device
Phys. Rev. E 114, 045203 – Published 5 October, 2026
DOI: https://doi.org/10.1103/dzw3-kdbt
Abstract
The induced magnetic field in an applied field magnetoplasmadynamic discharge device is a key physical quantity for plasma transport and electromagnetic feedback in the plasma discharge process. To clarify its spatial evolution and the associated driving mechanisms under steady operating conditions, a two-dimensional axisymmetric multifluid numerical model is developed and applied to an applied field magnetoplasmadynamic (AF-MPD) discharge device designed by Joint Laboratory of Plasma and Propulsion. The results show that the flow-electromagnetic coupling in the discharge region exhibits pronounced spatial partitioning: magnetic diffusion prevails in the upstream near-axis region adjacent to the cathode; the Hall effect prevails in the midstream near-axis region; in the downstream near-axis jet region, magnetic convection has the advantage, whereas in the anode and peripheral plume region, the Hall effect becomes the dominant mode governing the azimuthal induced magnetic field. Operating conditions modify the prevailing plasma transport modes: increasing the applied magnetic field strength suppresses cross-field transport and shifts the downstream near-axis region from convection-prevailed mode toward a Hall-prevailed mode; conversely, increasing the discharge current enhances local ionization and collisional processes, reducing the relative importance of the Hall effect and gradually promoting convection-prevailed mode in the midstream and downstream near-axis regions. The axial and radial induced magnetic fields are primarily generated by the electron azimuthal current, producing paramagnetic behavior inside the cathode cavity and diamagnetic behavior outside the cathode exit. The formation of this spatial topology results from the competition between the driven terms by the electric field and the electron pressure gradient, the latter being jointly modulated by the gradients of electron temperature and number density. These results provide new insight into plasma transport and electromagnetic coupling in the AF-MPD discharge device.
