Two-dimensional Model of an Electromagnetic Layer for the Mitigation of Communications Blackout

Kim, Minkwan; Keidar, Michael; Boyd, Iain D.

doi:10.2514/6.2009-1232

Cited by 13 publications

(15 citation statements)

References 9 publications

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“…The critical densities for L-band and S-band communications are 3.53 × 10 16 m −3 and 6.54 × 10 16 m −3 , respectively. 5 This result is consistent with the fact that the blackout of OREX actually started at 80 km and ended at 50 km. 30 Figure 8 shows the comparison with the OREX measurement of electron number densities by an electrostatic probe mounted on the conical flank before the probe shoulder 29 and the simulation result of LeMANS and indicates that LeMANS underestimates the electron number density of the OREX reentry.…”

Section: B Boundary Conditionssupporting

confidence: 86%

“…4 Developing solutions that allow communication through a plasma layer are a high priority because of flight safety, catastrophe analysis, and mission success. 5 During 10 minutes of radio blackout, a hypersonic vehicle could fly thousands of miles without guidance from a ground station or GPS satellite. It is clearly a flight safety issue for a manned hypersonic or reentry vehicle.…”

Section: Introductionmentioning

confidence: 99%

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Numerical Modeling of Plasma Manipulation Using an ExB Layer in the Hypersonic Boundary Layer

Kim

Boyd²,

Keidar

2009

40th AIAA Plasmadynamics and Lasers Conference

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When a vehicle flies with hypersonic velocity or re-enters the atmosphere, a weakly ionized plasma layer is generated around the vehicle due to the shock heated air. Since the created plasma layer has a high plasma number density, the vehicle has a communication problem known as radio blackout. In this study, we illustrate that an applied ExB layer can manipulate the plasma density in a specific region. The manipulated plasma reduces radio wave attenuation in the plasma layer and provides the possibility for communication during radio blackout. The possibility of the ExB layer mitigation scheme is evaluated in a realistic operating condition for a hypersonic flow in terms of signal attenuation.

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Section: B Boundary Conditionssupporting

confidence: 86%

Section: Introductionmentioning

confidence: 99%

Numerical Modeling of Plasma Manipulation Using an ExB Layer in the Hypersonic Boundary Layer

Kim

Boyd²,

Keidar

2009

40th AIAA Plasmadynamics and Lasers Conference

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“…For the hot electrons, we use the continuity equation to express and use the following relation obtained from the linearized equation of motion: (18) Thus (19) where is the Debye radius of the hot electrons defined as (20) where and are the thermal speed and plasma frequency of the hot electrons. On substituting (17) and (19) in (15), we obtain the following equation for EAW: (21) with (22) where is the wave number of EAW in our composite medium. Thus, the dispersion relation for EAW is given as (23) Notice that in contrast to EMW the plasma frequency is now the upper cutoff frequency.…”

Section: Electron Acoustic Wavesmentioning

confidence: 99%

“…Two articles that summarize early ideas are those of Rawhouser [5] and Rybak [14]. More recent ideas put forward are: three-wave scattering process [15], [16], Hall effect drift [17], electrostatic manipulation [17]- [19], and resonant transmission [20], [21]. These schemes exploit the wave phenomenology in the plasma sheath to transmit signals across the sheath.…”

Section: Introductionmentioning

confidence: 99%

Radiation Characteristics of Antennas Embedded in a Medium With a Two-Temperature Electron Population

Mudaliar

Sotnikov

2012

IEEE Trans. Antennas Propagat.

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It is well-known that low-frequency electromagnetic (EM) signals are heavily attenuated in a medium with dense electron population. All signals below the plasma frequency of the medium get cut off. If we create in this medium, a small population of relatively hot electrons the composite medium then supports low-frequency electrostatic oscillations known as electron acoustic waves (EAW) [e.g., Gary and Tokar, Phys. Fluids 28, 2439]. The dispersion relation of this composite medium shows that it supports EAW in the frequency band where EM signals are cut off. Thus, it is possible, in principle, to employ EAW to transmit signals across an overdense plasma medium. Our primary interest in this paper is to study the radiation characteristics of a source current distribution embedded in a half-space of our composite medium. To enable this, we derive the Green's functions for our problem and, hence, study the radiation characteristics of antennas. When the source signal frequency is below the plasma frequency, only EAW exist in the composite medium, while only EM waves can exist in the free space above. We find that the far-zone radiation fields of any current distribution consist only of -polarized waves. Explicit expressions for the radiated fields are obtained for horizontally-and vertically-polarized Hertzian dipoles embedded in our composite medium. We, hence, find that in both cases the radiation patterns are skewed towards the horizon. In particular, we find that the radiation pattern of a horizontal dipole has two lobes as opposed to one in the underdense case.

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“…In 2008, Keidar et al studied the influence of plasma on electromagnetic wave attenuation by theoretically examining applied electric and magnetic fields [12]. In 2009, Kim et al used a 2D magnetic structure based on experimental data to determine if a 2D magnetic field model would be more effective than a 1D magnetic field model [13].…”

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confidence: 99%

Spatial Distribution of Magnetic Field Under Spherical Shell Plasma

Song¹,

Yan²,

Ma³

et al. 2018

PIER M

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Abstract-Magnetic field intensity is modeled using Laplacian equations to study the spatial distribution of magnetic field under spherical shell plasma. The influences of different internal and external radii are also considered. In addition, the magnetic field calculation of plasma space is analyzed. The main conclusions are as follows. The external uniform magnetic field H 0 is the scalar magnetic bit, and the magnetic charge of the shell of the plasma is equivalent to that of a magnetic dipole. The magnetic field in the spherical shell is a superposition of a uniform field and a magnetic dipole field. The uniform field is composed of an externally applied uniform field H 0 and a uniform field generated by the magnetic charge on the outer surface of the ball. The magnetic dipole field is generated by the magnetic charge on the inner surface of the shell, and the inside of the shell is a uniform magnetic field. When μ 2 /μ 1 is high and a/b is low, the ratio of the magnetic field strength H 3 (the region is r < a) to the magnetic field strength H 0 (the region is r > b) is low. By contrast, when μ 2 /μ 1 and a/b are high, the ratio of the magnetic field strength H 3 to the magnetic field strength H 0 is high. When the magnetic permeability of the inner object is small and the spherical shell is thick, the produced plasma sheath is thick, and the external magnetic field in the spherical shell is weak. Therefore, when the shielding effect is good, the possibility that the "black barrier" phenomenon will occur is high, and ground radar detection will be difficult.

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Two-dimensional Model of an Electromagnetic Layer for the Mitigation of Communications Blackout

Cited by 13 publications

References 9 publications

Numerical Modeling of Plasma Manipulation Using an ExB Layer in the Hypersonic Boundary Layer

Numerical Modeling of Plasma Manipulation Using an ExB Layer in the Hypersonic Boundary Layer

Radiation Characteristics of Antennas Embedded in a Medium With a Two-Temperature Electron Population

Spatial Distribution of Magnetic Field Under Spherical Shell Plasma

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