Effects of Nonuniform Magnetic Fields on the “Magnetic Window” in Blackout Mitigation

Zhou, Hui; Li, Xiaoping; Liu, Yanming; Bai, Bowen; Xie, Kai

doi:10.1109/tps.2016.2636371

Cited by 22 publications

(5 citation statements)

References 15 publications

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“…Since the application of magnetic field makes a significant difference in the high electron density cases, it turns out that an inhomogeneous magnetic field can be a better choice for inhomogeneous plasmas. In [33], which is one of the few works addressing the effects of inhomogeneous magnetic field on blackout mitigation, the results indicate that the width of stopband increases due to additional narrow absorption bands. Therefore, it is necessary to investigate inhomogeneous magnetic field effect on the bandwidth and compare it to the case of uniform magnetic field.…”

Section: Resultsmentioning

confidence: 99%

Numerical study of the homogeneous and inhomogeneous magnetic field effects on the plasma‐based radar cross‐section reduction

Foroutan

2020

IET Radar, Sonar & Navigation

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Section: Resultsmentioning

confidence: 99%

Numerical study of the homogeneous and inhomogeneous magnetic field effects on the plasma‐based radar cross‐section reduction

Foroutan

2020

IET Radar, Sonar & Navigation

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“…According to research by the National Aeronautics and Space Administration (NASA), the electron density of a plasma sheath perpendicular to the hypersonic target surface approximately follows a double Gaussian distribution [25]. For the convenience of analysis, a multi-layer uniform structure is used to simulate a general non-uniform plasma sheath (assumed as N layers in Figure 2).…”

Section: Phase Screen Model In Non-uniform Plasma Sheathmentioning

confidence: 99%

Polarization Characteristics Distortion for L-Band Fully Polarimetric Radar Subject to Magnetized Plasma Sheath

Guo,

Hu,

Shen

et al. 2024

Remote Sensing

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High-velocity reentry objects suffer from plasma sheath during reentry through the atmosphere, which affects the propagation characteristics of radar signals. The existing research mainly focuses on the time-frequency characteristics of radar signals, neglecting the polarization within the geomagnetic environment. In this article, the distortion of polarization characteristics for L-band fully polarimetric radar is analyzed, and the influence of the geomagnetic field is evaluated. Based on the Appleton–Hartree formula, the refractive index of the plasma sheath considering the geomagnetic field is derived and analyzed. The error model for the polarization deflection (PD) of radar waves is then established based on the phase screen model. The magnetized plasma sheath causes the deflection of the polarization plane for the radar signal, leading to distortion in the polarization characteristics and the attenuation of the echo amplitude. Considering the typical parameters of the plasma sheath, the influences of the electron density, collision frequency, the geomagnetic field and the radar frequency are analyzed quantitatively. Specifically, the PD anomaly phenomenon is analyzed and the corresponding analytical result of radar frequency is also derived. The relationship between the geomagnetic field and the PD, as well as the attenuation, is considered to be approximately linear. The absorption attenuation is primarily influenced by collision frequency and is immune to the geomagnetic field. In addition, the increasing electron density expands them, whereas the radar frequency and the collision frequency have the opposite effect. Simulations with real SAR data from ALOS-2 demonstrate the distortions resulting from the magnetized plasma sheath on the radar echoes in an L-band fully polarimetric radar system.

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“…Magnetization of the plasma sheath first pointed out by Hodara in 1961, [9] which create a pass band (called "magnetic window") and allow the EM wave of a specific frequency to pass through the plasma sheath in the direction of the static magnetic field. Since then, many relevant studies have been carried out, [10][11][12][13] including simulation of sub-THz wave propagation in a magnetized non-uniform plasma sheath, [14] effects of nonuniform magnetic fields on the "magnetic window", [15] and study of electromagnetic wave propagation in an overdense magnetized collisional plasma sheath. [16] However, most of these studies focused on the effects of the non-uniform magnetic field, and studies on electron density, incident angle, and other relevant parameters are very limited.…”

Section: Introductionmentioning

confidence: 99%

Characteristics of the electromagnetic wave propagation in magnetized plasma sheath and practical method for blackout mitigation

Wu 吴,

Zhang 张,

Dong 董

et al. 2024

Chinese Phys. B

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“Magnetic window” is considered as an effective method to solve the communication blackout issue. COMSOL software package based on the finite element method is utilized to simulate the propagation of right-handed circularly polarized wave in the magnetized plasma sheath. We assume a double Gaussian model of electron density and an exponential attenuation model of magnetic field. The propagation characteristics of right-handed circularly polarized wave are analyzed by the observation of the reflected, transmitted and loss coefficient. The numerical results show that the propagation of right-handed circularly polarized wave in the magnetized plasma sheath varies for different incident angles, collision frequencies, non-uniform magnetic fields and non-uniform plasma densities. We notice that reducing the wave frequency can meet the propagation conditions of whistle mode in the weak magnetized plasma sheath. And the transmittance of whistle mode is less affected by the variation of the electron density and the collision frequency. It can be used as a communication window.

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Effects of Nonuniform Magnetic Fields on the “Magnetic Window” in Blackout Mitigation

Cited by 22 publications

References 15 publications

Numerical study of the homogeneous and inhomogeneous magnetic field effects on the plasma‐based radar cross‐section reduction

Numerical study of the homogeneous and inhomogeneous magnetic field effects on the plasma‐based radar cross‐section reduction

Polarization Characteristics Distortion for L-Band Fully Polarimetric Radar Subject to Magnetized Plasma Sheath

Characteristics of the electromagnetic wave propagation in magnetized plasma sheath and practical method for blackout mitigation

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