Experimental study on the plasma regulation method based on a time-varying electromagnetic field

This paper proposes a novel plasma regulation method based on time-varying E × B fields to address communication blackout issues during hypersonic vehicle reentry. In conventional static E × B fields, the Debye shielding effect causes the current density j in plasma beyond the Debye radius to decay to zero (j = 0 A/m2), resulting in ineffective electron density reduction. To overcome this limitation, this paper introduces a time-varying electric field to enhance the current density in the plasma, thereby mitigating the Debye shielding effect. Through synchronized control of time-varying electric and magnetic fields (same frequency and phase), we maintain a consistent Lorentz force direction (f = J × B), effectively reinforcing electron repulsion. Experimental verification utilized low-pressure glow discharge (14 Pa) to generate uniform plasma (88% uniformity in the central region). A transverse 7 cm low-electron-density region was achieved with a maximum reduction of 70% at B = 0.05 T and U0 = 1000 V. This breakthrough not only validates the time-varying electric field’s capability to enhance conduction currents but also provides a new pathway for practical engineering applications of magnetic window techniques.