Electromagnetic reduction of plasma density during atmospheric reentry and hypersonic flights

As a vehicle reenters or travels through the atmosphere at hypersonic velocities, the shock-heated air surrounding the vehicle becomes weakly ionized. This plasma layer causes an important systems operation problem known as communications blackout or radio blackout. At sufficiently high plasma density, the plasma layer either reflects or attenuates radiowave communications to and from the vehicle. In this paper, we study the application of electric and magnetic fields to reduce the plasma density. Specifically, an E x B crossed-field configuration is proposed. Both analytical and numerical results suggest that significant reduction of the plasma density is possible at large altitudes. For instance, plasma density reduction by a factor of 10 is predicted in the case of 81 km and a magnetic field of about 0.1 T. Theoretical results suggest that significant reduction of the plasma density is possible, enabling radio communication across the plasma layer. The benefit of the reduced plasma density in terms of electromagnetic wave absorption across the plasma layer is estimated.