scholarly journals Absorption of Electromagnetic Waves in Non-Dispersive Plasma due to Effect of Ponderomotive Force

2020 ◽  
Vol 6 (1) ◽  
pp. 123-130
Author(s):  
P. K. Thakur ◽  
S. Bhaila ◽  
J. J. Nakarmi
Keyword(s):  
Electromagnetic Wave ◽  
Absorption Coefficient ◽  
Electromagnetic Waves ◽  
Unit Volume ◽  
Ponderomotive Force ◽  
Debye Length ◽  
Angular Frequency ◽  
Incident Laser ◽  
Electron Fluid

The absorption coefficient of electromagnetic wave propagating through overdense absorbing plasma is calculated by using Fresnel’s formula. Also, the force acting per unit volume of the electron fluid is calculated along z direction. The Fresnel’s formula is reduced in terms of conductivity and angular frequency so that nature of absorption coefficient with respect to conductivity of plasma and angular frequency of wave is studied, with the assumption that conductivity and angular frequency are two independent terms. By keeping conductivity of plasma constant, it is seen that the absorption coefficient is increased with increase in angular frequency and also absorption coefficient has the lowest value for the highest value of conductivity. At constant angular frequency of incidence, the absorption coefficient is decreased with increase in conductivity and also absorption coefficient has the highest value of angular frequency of incidence. Also the nature of force on the plasma is studied by considering that the conductivity of plasma is very large with compare to angular frequency of incident laser. The expression of absorption coefficient is separated into real and imaginary parts, and then plots are studied with respect to these parts. It is found that in both cases, the force on plasma is existed for short in time and distance, and then damps exponentially. Also, the variation of potential with distance is cleared that the potential is shielded within multiple distance of Debye length.

scholarly journals Excitation of ion wakefields by electromagnetic pulses in dense plasmas

2009 ◽  
Vol 75 (1) ◽  
pp. 15-18 ◽  
Author(s):  
P. K. SHUKLA
Keyword(s):  
Wave Equation ◽  
Electromagnetic Wave ◽  
Electromagnetic Waves ◽  
Electromagnetic Pulse ◽  
Dense Plasma ◽  
Ponderomotive Force ◽  
Electromagnetic Pulses ◽  
Dense Plasmas ◽  
High Energies

AbstractThe excitation of electrostatic ion wakefields by electromagnetic pulses in a very dense plasma is considered. For this purpose, a wave equation for the ion wakefield in the presence of the ponderomotive force of the electromagnetic waves is obtained. Choosing a typical profile for the electromagnetic pulse, the form of the ion wakefields is deduced. The electromagnetic wave-generated ion wakefields can trap protons and accelerate them to high energies in dense plasmas.

scholarly journals Generation of magnetic fields by the ponderomotive force of electromagnetic waves in dense plasmas

2009 ◽  
Vol 76 (1) ◽  
pp. 25-28 ◽  
Author(s):  
P. K. SHUKLA ◽  
NITIN SHUKLA ◽  
L. STENFLO
Keyword(s):  
Electromagnetic Wave ◽  
Magnetic Fields ◽  
Electromagnetic Waves ◽  
Ponderomotive Force ◽  
Intense Laser ◽  
Quantum Plasma ◽  
Dense Plasmas ◽  
Solid Density ◽  
Astrophysical Objects ◽  
Density Plasma

AbstractWe show that the non-stationary ponderomotive force of a large-amplitude electromagnetic wave in a very dense quantum plasma with streaming degenerate electrons can spontaneously create d.c. magnetic fields. The present result can account for the seed magnetic fields in compact astrophysical objects and in the next-generation intense laser–solid density plasma interaction experiments.

scholarly journals Magnetization of Rydberg plasmas by electromagnetic waves

2009 ◽  
Vol 76 (1) ◽  
pp. 19-23 ◽  
Author(s):  
J. T. MENDONÇA ◽  
NITIN SHUKLA ◽  
P. K. SHUKLA
Keyword(s):  
Electromagnetic Wave ◽  
Magnetic Fields ◽  
High Frequency ◽  
Large Amplitude ◽  
Electromagnetic Waves ◽  
Ponderomotive Force

AbstractIt is shown that the ponderomotive force of a large-amplitude electromagnetic wave in Rydberg plasmas can generate quasi-stationary magnetic fields. The present result can account for the origin of seed magnetic fields in the ultracold Rydberg plasmas when they are irradiated by the high-frequency electromagnetic wave.

Detection of delamination in composites by using electromagnetic penetrating radar

2014 ◽  
Vol 5 (2) ◽  
pp. 151-156
Author(s):  
Z. Mechbal ◽  
A. Khamlichi
Keyword(s):  
Electromagnetic Wave ◽  
Electromagnetic Waves ◽  
Electromagnetic Wave Propagation ◽  
Wave Reflection ◽  
Image Features ◽  
Partial Reflection ◽  
Straight Path ◽  
Reflected Signal ◽  
Short Time ◽  
Intervening Factors

Composites made from E-glass/epoxy or aramid/epoxy are frequently used in aircraft and aerospace industries. These materials are prone to suffer from the presence of delamination, which can reduce severely the performance of aircrafts and even threaten their safety. Since electric conductivity of these composites is rather small, they can propagate electromagnetic waves. Detection of delamination damage can then be monitored by using an electromagnetic penetrating radar scanner, which consists of emitting waves having the form of short time pulses that are centered on a given work frequency. While propagating, these waves undergo partial reflection when running into an obstacle or a material discontinuity. Habitually, the radar is moved at constant speed along a straight path and the reflected signal is processed as a radargram that gives the reflected energy as function of the two-way time and the antenna position.In this work, modeling of electromagnetic wave propagation in composites made from E-glass/epoxy was performed analytically. The electromagnetic wave reflection from a delamination defect was analyzed as function of key intervening factors which include the defect extent and depth, as well as the work frequency. Various simulations were performed and the obtained results have enabled to correlate the reflection pattern image features to the actual delamination defect characteristics which can provide quantification of delamination.

New Approach to the Theory of Circular Dichroism

1998 ◽  
Vol 63 (8) ◽  
pp. 1187-1201 ◽  
Author(s):  
Jaroslav Zamastil ◽  
Lubomír Skála ◽  
Petr Pančoška ◽  
Oldřich Bílek
Keyword(s):  
Electromagnetic Wave ◽  
Circular Dichroism ◽  
Electromagnetic Waves ◽  
Maxwell Equations ◽  
Optically Active ◽  
Semiclassical Approach ◽  
New Approach ◽  
Isotropic Media ◽  
New Formula ◽  
Circular Dichroïsm

Using the semiclassical approach for the description of the propagation of the electromagnetic waves in optically active isotropic media we derive a new formula for the circular dichroism parameter. The theory is based on the idea of the time damped electromagnetic wave interacting with the molecules of the sample. In this theory, the Lambert-Beer law need not be taken as an empirical law, however, it follows naturally from the requirement that the electromagnetic wave obeys the Maxwell equations.

scholarly journals Preparation and electromagnetic properties characterization of reduced graphene oxide/strontium hexaferrite nanocomposites

2020 ◽  
Vol 9 (1) ◽  
pp. 105-114 ◽  
Author(s):  
Shumin Du ◽  
Huaiyin Chen ◽  
Ruoyu Hong
Keyword(s):  
Electromagnetic Wave ◽  
Environmental Pollution ◽  
Electromagnetic Interference ◽  
Electromagnetic Waves ◽  
Rapid Development ◽  
Living Environment ◽  
World Health ◽  
Electromagnetic Properties ◽  
Strontium Hexaferrite ◽  
Wave Radiation

AbstractWith the rapid development of electronics and information technology, electronics and electrical equipment have been widely used in our daily lives. The living environment is full of electromagnetic waves of various frequencies and energy. Electromagnetic wave radiation has evolved into a new type of environmental pollution that has been listed by the WHO (World Health Organization) as the fourth largest source of environmental pollution after water, atmosphere, and noise. Studies have shown that when electromagnetic wave radiation is too much, it can cause neurological disorders. And electromagnetic interference will cause the abnormal operation of medical equipment, precision instruments and other equipment, and therefore cause incalculable consequences. Therefore, electromagnetic protection has become a hot issue of concern to the social and scientific circles.

Transmissive 2-bit anisotropic coding metasurface

2022 ◽  
Author(s):  
Pengtao Lai ◽  
Zenglin Li ◽  
Wei Wang ◽  
Jia Qu ◽  
Liang Wei Wu ◽  
...  
Keyword(s):  
Angular Momentum ◽  
Electromagnetic Wave ◽  
Circular Polarization ◽  
Orbital Angular Momentum ◽  
Electromagnetic Waves ◽  
Beam Splitter ◽  
Far Field ◽  
Polarization Conversion ◽  
Field Patterns ◽  
Phase Profile

Abstract Coding metasurfaces have attracted tremendous interests due to unique capabilities of manipulating electromagnetic wave. However, archiving transmissive coding metasurface is still challenging. Here we propose a transmissive anisotropic coding metasurface that enables the independent control of two orthogonal polarizations. The polarization beam splitter and the OAM generator have been studied as typical applications of anisotropic 2-bit coding metasurface. The simulated far field patterns illustrate that the x and y polarized electromagnetic waves are deflected into two different directions, respectively. The anisotropic coding metasurface has been experimentally verified to realize an orbital angular momentum (OAM) beam with l = 2 of right-handed polarized wave, resulting from both contributions from linear-to-circular polarization conversion and the phase profile modulation. This work is beneficial to enrich the polarization manipulation field and develop transmissive coding metasurfaces.

scholarly journals The scattering of light by turbid media.–Part II

1931 ◽  
Vol 131 (817) ◽  
pp. 464-475 ◽  
Keyword(s):  
Refractive Index ◽  
Absorption Coefficient ◽  
Spherical Shell ◽  
Direct Observation ◽  
Single Particle ◽  
Unit Volume ◽  
Incident Light ◽  
Parallel Beam ◽  
Photometric Observations ◽  
Transmission And Reflection

In Part I it was shown how the values of the transmission and reflection of a sheet of a medium containing particles in suspension can he calculated. First the amounts of light scattered in the forward and forward directions from a single particle were determined; from these results the transmission 1 and rejection R for diffuse incident light were found for a layer of the disusing medium, when the effects of boundary reflections are negligible. At this stage, the expressions developed apply to a mist or fog consisting of particles suspended in air. Finally it was shown how, if the particles are suspended in some other medium, having a different refractive index from that of air, the transmission and reflection ז and p can be expressed in terms of T and R and the surface rejection coefficients. The more general expressions, for the case when the incident light is a parallel beam, were also developed. We shall now show how the absorption coefficient μ can be determined from photometric observations. As a check on the theory, we shall deduce the diameter D of the particles and the number N present per unit volume and compare these calculated values with those found by direct observation, Finally, the necessary modifications of the theory will be made to cover the case when the diffusing medium is in the form of a spherical shell.

scholarly journals The Electromagnetic Wave Absorption Performance and Mechanical Properties of Cement-Based Composite Material Mixed with Functional Aggregates with High Fe2O3 and SiC

2021 ◽  
Vol 31 (4) ◽  
pp. 249-255
Author(s):  
Zuoqun Zhang ◽  
Chaoshan Yang ◽  
Hua Cheng ◽  
Xiaohan Huang ◽  
Yuhao Zhu
Keyword(s):  
Composite Material ◽  
Electromagnetic Wave ◽  
Electromagnetic Waves ◽  
Building Materials ◽  
Magnetic Loss ◽  
Frequency Range ◽  
Electromagnetic Wave Absorption ◽  
Wave Absorption ◽  
Test Board ◽  
Absorption Performance

Now there’re many researches on the electromagnetic radiation protection function of the cement-based electromagnetic wave absorbing materials, such materials have been widely used in various types of buildings. This paper proposed an idea for preparing a cement-based composite material by mixing functional aggregates with high content of Fe2O3 and SiC, that is, adding Fe3O4 powder and nano-SiC of different contents in the clay, and then sintering at 1190℃; the prepared aggregates showed obvious magnetic loss and dielectric loss to electromagnetic waves, and the numerical tube pressure could reach 16.83MPa. The double-layer reflectivity test board made of functional aggregates showed excellent electromagnetic wave absorption performance, its reflection loss was less than -10dB in the frequency range of 8~18GHz (corresponding to energy absorption greater than 90% EM), and its maximum RL reached -12.13dB. In addition, the compressive strength of the cement-based composite material at the age of 28 days reached 50.1 MPa, which can meet the strength requirements of building materials.

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