Reduction of attenuation of e.m wave inside plasma formed during supersonic or hypersonic re-entry of missile like flight vehicles by the application of D.C magnetic field — A technique for mitigation of RF Blackout

摘要

During re-entry of missile like flight vehicle at supersonic or hypersonic velocity, a high density non-uniform and non-equilibrium plasma sheath is formed around the flight vehicle. This high density plasma has the characteristics to reflect and absorb propagating electromagnetic (e.m) wave which is transmitted to maintain the RF link in between the re-entering flight vehicle and ground based telemetry and radar stations. This paper presents the analysis of attenuation characteristics of e.m wave inside re-entry plasma sheath and explains the region of frequencies of RF-Blackout. It also analyzes the propagation characteristics inside the re-entry plasma in presence of D.C magnetic field applied in the direction normal to the wave front. Finally from the analysis, it finds the strength of magnetic field needed for mitigation of RF Blackout and the problem of dispersion of onboard transmitted signal in the region of frequencies below plasma resonant frequencies while S or C or X band frequencies are in use for transmission of onboard information.