Optical signatures of electrically charged particles: Fundamental problems and solutions

Klačka, J.; Kocifaj, Miroslav; Kundracík, František; Videen, Gorden

doi:10.1016/j.jqsrt.2015.05.009

Cited by 25 publications

(5 citation statements)

References 24 publications

(35 reference statements)

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“…Note that Takahashi (1973) estimated the maximum potential of charged cloud droplets is about 700 V, so 100 V is not an unrealistic value. In general, it is difficult to retrieve the charging information experimentally, although we have developed a method to characterize a cloud of charged particles based on ground-based or spaceborne radar backscatter data (Kocifaj, Klačka, et al, 2015). Alternatively, some parameters of charged particles could be inferred by matching modeled to observed radar power ratios (Xie et al, 2020).…”

Section: Anomalous Mw Attenuation and Its Possible Relation To The Charged Particlesmentioning

confidence: 99%

“…While such occurrences as this one at frequencies

f <

48 GHz or more conservatively at

f <

37 GHz (Vishvakarma & Rai, 1993) might be attributed to the particle sizes lying outside the limit of the Rayleigh approximation, inconsistencies also have been recorded during the Gulf War at frequencies of about 11 GHz (Chen, 1991), which places the particles well within the approximation. Recently, it has been found that excess charge on a particle surface can change their optical properties, resulting in increased absorption (Klačka et al., 2015). It has been shown only recently that net charge on aerosol particles can influence the radar ratio of the received to transmitted power (Xie et al., 2020), which determines the range of operation.…”

Section: Introductionmentioning

confidence: 99%

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The Nature, Amplitude and Control of Microwave Attenuation in the Atmosphere

et al. 2021

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Microwave (MW) attenuation plays a critical role in constructing communication networks. It also can be a useful tool in the meteorological and optical communities for radar and microwave imaging applications. Because most atmospheric constituents (large hydrometeors being an exception) are very small compared to MW wavelengths, data analysis is typically performed using conventional Rayleigh theory; however, some anomalous observations have proven difficult to explain. We present the results of the first systematic numerical computations over a wide range of aerosol properties. We demonstrate that it is possible to perform mass computations of aerosol loading, which is an important climate parameter. We show that discrepancies found between theoretical predictions and observations can be attributed to the effect of the expected charge acquired by the dust particles through contact electrification occurring in dust storms. While frequencies below 10 GHz normally allow for long‐distance signal transmission, the charge‐induced resonances in particles can preferentially amplify the low‐frequency MW attenuation by a factor of 10 or more, depending on their surface electric potential. In addition, we find electrically charged particles dispersed in a local atmosphere as a potential tool for the controlled manipulation of MW attenuation.

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Section: Anomalous Mw Attenuation and Its Possible Relation To The Charged Particlesmentioning

confidence: 99%

“…While such occurrences as this one at frequencies

f <

48 GHz or more conservatively at

f <

Section: Introductionmentioning

confidence: 99%

The Nature, Amplitude and Control of Microwave Attenuation in the Atmosphere

et al. 2021

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“…Different from the absorption-type [11] transparent electromagnetic shielding materials, homogeneous transparent conductive thin films without periodic patterns can achieve reflection-type electromagnetic shielding functionality [12]. Enhanced microwave absorption is also observed in a random disperse system containing conductive (charged) particles [13,14]. Generally, the reflection-type transparent electromagnetic shielding materials can work over a broader bandwidth than the absorption-type ones.…”

Section: Introductionmentioning

confidence: 99%

Optically Transparent Microwave Shielding Hybrid Film Composited by Metal Mesh and Graphene

Wang¹,

Wang²,

Ren³

et al. 2021

PIER

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Transparent conducting materials with the ability of broadband electromagnetic shielding have a widespread range of applications in aerospace, medical equipment, and electronic communications. Achieving enhanced electromagnetic shielding effect without sacrificing much optical transparency is the technical trend in both academia and industries. Here, we experimentally propose a flexible hybrid film constructed by nano-printing based metal meshes and a graphene coating for the transparent electromagnetic shielding application. Numerical analysis is carried out to investigate optimal balance between electromagnetic shielding and optical transparency. In the experiment, enhanced shielding ability of hybrid film is observed without excessively sacrificing optical transmittance, compared to the reference group (the case only with metal mesh). Our work provides a hybrid platform for the high-performance optically transparent shielding materials for electromagnetic environment safety protection.

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“…We would like to state that our theoretical frame is under the assumption of uniform charge distribution on the particle surface. Uniform charge distribution is typical for particles of simple geometry such as spherical particles considered in this work, to which separation of variables method is applicable to find scattered electric and magnetic fields (Klačka et al, 2015a). In the Clustered charged particles section, the T-matrix formulism with modified boundary condition to calculate the electromagnetic response of clustered charged spherical particles is described.…”

Section: Introductionmentioning

confidence: 99%

Electromagnetic Response of Clustered Charged Particles

Zhou

et al. 2021

Front. Mater.

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Electromagnetic response of clustered charged particles is the foundation of electromagnetic wave interaction with various natural phenomena, such as sandstorm, cloud, and volcano eruption. Previous studies usually employed assumption of independent charged particles, without considering the coupling between them. Here, we build up a general numerical model considering the multiple scattering effect, and test it with a charged two- and four-particle system. The numerical results show that independence assumption fails, while the number density of clustered charged particles is getting larger. This work may pave the way for deeper understanding on the electromagnetic interaction of clustered charged particles.

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Optical signatures of electrically charged particles: Fundamental problems and solutions

Cited by 25 publications

References 24 publications

The Nature, Amplitude and Control of Microwave Attenuation in the Atmosphere

The Nature, Amplitude and Control of Microwave Attenuation in the Atmosphere

Optically Transparent Microwave Shielding Hybrid Film Composited by Metal Mesh and Graphene

Electromagnetic Response of Clustered Charged Particles

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