Electromagnetic Reduction of Plasma Density During Atmospheric Reentry and Hypersonic Flights

Abstract

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 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.

Effects of magnetized plasma on the propagation properties of obliquely incident THz waves

“…1 The propagating electromagnetic (EM) waves might be reflected and attenuated by the plasma sheath to a point where total RF blackout can occur. 2,3 The process of EM wave propagation through plasma sheath is complex and can be influenced by many factors 4 (such as electron density, plasma collision frequency, etc. ), but its mechanism is not clear yet.…”

Blackout mitigation during space vehicle re-entry

“…Subsequently, the atmposhpheric layer around the vehicle heats up reaching very high temperatures creating a layer of plasma around it. This plasma layer has an electron density in the order of 10 15 -10 19 m -3 [2] forcing electrons to oscillate at plasma frequency about the heavy atoms of NO + [3]. By virtue of its characteristics, it acts as a shield for all frequencies lower than the plasma frequency thereby leading to the loss of communication signal between space vehicle and the control station.…”

A new method for removing the blackout problem on reentry vehicles

“…1 Many different methods for removing the plasma layer have been proposed [2][3][4] and supported by theory, [5][6][7][8][9] computer simulations, 10,11 and laboratory experiments. [12][13][14] The plasma can be quenched by gas releases (H 2 O, SF 6 ), static magnetic fields allowing propagation of whistler modes, 15 electron acoustic modes occurring in non-Maxwellian plasmas 16 or nonlinear waves 17 and E Â B flows created by discharges on the surface of the vehicle have been proposed and partly tested in laboratory plasmas. 14 The present paper describes a simpler method to remove the blackout layer, which is based on a laboratory observation.…”