TRANSMISSION AND REFLECTION OF ELECTROMAGNETIC WAVES AT A PLASMA BOUNDARY FOR ARBITRARY ANGLES OF INCIDENCE

1961 ◽  
Vol 39 (11) ◽  
pp. 1544-1562 ◽  
Author(s):  
K. A. Graf ◽  
M. P. Bachynski
Keyword(s):  
Electromagnetic Waves ◽  
Plane Electromagnetic Wave ◽  
Space Plasma ◽  
Plasma Boundary ◽  
Brewster Angle ◽  
Angle Of Incidence ◽  
Elliptical Polarization ◽  
Plasma Parameters ◽  
Polarized Waves ◽  
Transmission And Reflection

The interaction of a plane electromagnetic wave with a flat free-space – plasma interface has been considered for arbitrary angles of incidence. It is shown that the plasma can support independent horizontally and vertically polarized waves. Expressions and graphical representations are given showing the amount of energy entering the plasma as a function of angle of incidence and plasma parameters. The vertically polarized case shows a maximum in the energy entering the plasma at the "Brewster angle". For a lossy plasma, at this maximum, there will be reflection. Loci of constant Brewster angle appear as concentric curves centered on the origin of the complex dielectric coefficient plane.The elliptical polarization of a plane wave reflected from the interface, when a wave with equal horizontally and vertically polarized components is incident on the interface, suggests the similarity of lossless plasmas to ordinary dielectrics and of lossy plasmas to metals.

ELECTROMAGNETIC WAVES IN A BOUNDED, ANISOTROPIC PLASMA

1962 ◽  
Vol 40 (7) ◽  
pp. 887-905 ◽  
Author(s):  
K. A. Graf ◽  
M. P. Bachynski
Keyword(s):  
Magnetic Field ◽  
Static Magnetic Field ◽  
Electromagnetic Waves ◽  
Plane Electromagnetic Wave ◽  
Plasma Boundary ◽  
Plasma Properties ◽  
Magnetic Field Data ◽  
Reflected Waves ◽  
Quartic Equation ◽  
The Magnetic Field

The interaction of a plane, electromagnetic wave with a flat, uniform free-space – plasma interface in a static magnetic field has been considered for arbitrary angles of incidence. The dispersion relation for the plasma is a complex quartic equation which reduces to a quadratic if the static magnetic field and plasma boundary are oriented along any one of the rectangular co-ordinate axes. (These axes need not simultaneously be the same for the plasma and the magnetic field.)Numerical results are presented for the attenuation and phase constants for each of the two possible waves in the plasma, for each orientation of the static magnetic field. Data are given for various angles of incidence, plasma properties, and orientations of the static magnetic field relative to the plasma boundary.Inspection of the fields in the plasma reveals some interesting aspects. In certain cases, waves which appear to move upward towards the plasma interface exist. Since these waves may carry energy into the plasma, they have been referred to as "backward" waves. Totally reflected waves which have both finite attenuation and finite phase coefficients can also exist in the plasma. These have been termed "modified Sommerfeld" waves.

Propagation of Strong-Field Modulated Electromagnetic Waves in Plasmas

1971 ◽  
Vol 49 (24) ◽  
pp. 3208-3220
Author(s):  
M. P. Bachynski ◽  
B. W. Gibbs
Keyword(s):  
Electron Temperature ◽  
Electromagnetic Waves ◽  
Strong Field ◽  
Plane Electromagnetic Wave ◽  
Low Frequency ◽  
Wave Form ◽  
Plasma Properties ◽  
Polarized Waves ◽  
Effective Collision Frequency ◽  
Low Frequency Waves

The distortion of the wave form of a modulated plane electromagnetic wave propagating in an anisotropic plasma has been experimentally investigated over a range of field strengths of the wave and plasma properties. By using right-hand circularly polarized waves, the effective frequency is [Formula: see text] (where ω is the r.f. radian frequency and ωb the cyclotron frequency) and hence the results are also applicable to the propagation of low-frequency waves in an isotropic plasma. Severe "overmodulation" of the wave form transmitted through the plasma is found in the regime [Formula: see text] where ν is the effective collision frequency for momentum transfer. The distortion of the wave form is found to increase with depth of modulation of the incident wave and decrease with increasing modulation frequency.The "demodulation" is in qualitative agreement with theory for an unmodulated wave with a non-Maxwellian (Druyvesteyn) velocity distribution for the electrons. Many of the effects of the modulation frequencies can also be qualitatively predicted by considering the variation of electron temperature in the presence of the strong-field modulated wave. A theory is developed for large changes in electron temperature induced by the incident field which shows that marked distortion of the modulation is possible.

scholarly journals Design and experimental analysis of dual-band polarization converting metasurface for microwave applications

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Bilawal Khan ◽  
Babar Kamal ◽  
Sadiq Ullah ◽  
Imran Khan ◽  
Jawad Ali Shah ◽  
...  
Keyword(s):  
Electromagnetic Waves ◽  
Polarization State ◽  
Plane Waves ◽  
Microwave Frequency ◽  
Dual Band ◽  
Orthogonal Polarization ◽  
Frequency Bands ◽  
Practical Applications ◽  
Sensor Applications ◽  
Polarized Waves

Abstract The manipulation of polarization state of electromagnetic waves is of great importance in many practical applications. In this paper, the reflection characteristics of a thin and dual-band metasurface are examined in the microwave frequency regime. The metasurface consists of a 22 × 22 element array of periodic unit cells. The geometry of the unit cell consists of three layers, including a 45° inclined dipole shape metal patch on top, which is backed by a 1.6 mm thick FR-4 substrate in the middle, and a fully reflective metallic mirror at the bottom. The proposed surface is exposed to horizontally (x) or vertically (y) polarized plane waves and the co and cross polarization reflection coefficients of the reflected waves are investigated experimentally in the 6–26 GHz frequency range. The metasurface is designed to convert incident waves of known polarization state (horizontal or vertical) to orthogonal polarization state (vertical and horizontal) in two distinct frequency bands, i.e. 7.1–8 GHz and 13.3–25.8 GHz. In these two frequency bands the simulated and experimental results are in good agreement. The polarization conversion ratio (PCR) of the surface is greater than 95% in the targeted frequency bands. A detailed parametric analysis of the metasurface is also discussed in this work and it has been estimated that the surface has the additional ability to convert linearly polarized waves to circularly polarized waves at several distinct frequencies. The proposed metasurface can be utilized in sensor applications, stealth technology, electromagnetic measurements, and antennas design.

scholarly journals Modelling the solar wind interaction with Mercury by a quasi-neutral hybrid model

2003 ◽  
Vol 21 (11) ◽  
pp. 2133-2145 ◽  
Author(s):  
E. Kallio ◽  
P. Janhunen
Keyword(s):  
Solar Wind ◽  
Plasma Physics ◽  
Hybrid Model ◽  
Space Plasma ◽  
Physical Processes ◽  
Space Plasma Physics ◽  
Solar Wind Interaction ◽  
Plasma Parameters ◽  
Advantages And Disadvantages ◽  
Self Consistent

Abstract. Quasi-neutral hybrid model is a self-consistent modelling approach that includes positively charged particles and an electron fluid. The approach has received an increasing interest in space plasma physics research because it makes it possible to study several plasma physical processes that are difficult or impossible to model by self-consistent fluid models, such as the effects associated with the ions’ finite gyroradius, the velocity difference between different ion species, or the non-Maxwellian velocity distribution function. By now quasi-neutral hybrid models have been used to study the solar wind interaction with the non-magnetised Solar System bodies of Mars, Venus, Titan and comets. Localized, two-dimensional hybrid model runs have also been made to study terrestrial dayside magnetosheath. However, the Hermean plasma environment has not yet been analysed by a global quasi-neutral hybrid model. In this paper we present a new quasi-neutral hybrid model developed to study various processes associated with the Mercury-solar wind interaction. Emphasis is placed on addressing advantages and disadvantages of the approach to study different plasma physical processes near the planet. The basic assumptions of the approach and the algorithms used in the new model are thoroughly presented. Finally, some of the first three-dimensional hybrid model runs made for Mercury are presented. The resulting macroscopic plasma parameters and the morphology of the magnetic field demonstrate the applicability of the new approach to study the Mercury-solar wind interaction globally. In addition, the real advantage of the kinetic hybrid model approach is to study the property of individual ions, and the study clearly demonstrates the large potential of the approach to address these more detailed issues by a quasi-neutral hybrid model in the future.Key words. Magnetospheric physics (planetary magnetospheres; solar wind-magnetosphere interactions) – Space plasma physics (numerical simulation studies)

ELECTROMAGNETIC LATERAL WAVES OBSERVED BY EARTH‐SOUNDING RADARS

Geophysics ◽  
1976 ◽  
Vol 41 (6) ◽  
pp. 1126-1132 ◽  
Author(s):  
John W. Clough
Keyword(s):  
Electromagnetic Waves ◽  
Critical Angle ◽  
Continuous Wave ◽  
Angle Of Incidence ◽  
Lateral Wave ◽  
Snell’S Law ◽  
Snell's Law ◽  
Low Amplitude

Electromagnetic waves refracted at the critical angle according to Snell's law give rise to the lateral wave. The low amplitude lateral wave is usually obscured by other waves when continuous wave sources are used. Using a pulsed source (radar) and continuously recording echoes reflected from within dielectric earth materials as a function of angle of incidence, records are produced which clearly show the lateral wave. In some earth‐probing applications, the lateral wave may predominate and proper identification of its characteristics is important.

The propagation of electromagnetic waves in a stratified medium

1929 ◽  
Vol 25 (1) ◽  
pp. 97-120 ◽  
Author(s):  
D. R. Hartree
Keyword(s):  
Refractive Index ◽  
Reflection Coefficient ◽  
Electromagnetic Waves ◽  
Stratified Medium ◽  
Simple Extension ◽  
Angle Of Incidence ◽  
First Approximation ◽  
Special Cases ◽  
Cartesian Coordinate ◽  
The Given

The equations of propagation of electromagnetic waves in a stratified medium (i.e. a medium in which the refractive index is a function of one Cartesian coordinate only—in practice the height) are obtained first from Maxwell's equations for a material medium, and secondly from the treatment of the refracted wave as the sum of the incident wave and the wavelets scattered by the particles of the medium. The equations for the propagation in the presence of an external magnetic field are also derived by a simple extension of the second method.The significance of a reflection coefficient for a layer of stratified medium is discussed and a general formula for the reflection coefficient is found in terms of any two independent solutions of the equations of propagation in a given stratified medium.Three special cases are worked out, for waves with the electric field in the plane of incidence, viz.(1) A finite, sharply bounded, medium which is “totally reflecting” at the given angle of incidence.(2) Two media of different refractive index with a transition layer in which μ2 varies linearly from the value in one to the value in the other.(3) A layer in which μ2 is a minimum at a certain height and increases linearly to 1 above and below, at the same rate.For cases (2) and (3) curves are drawn showing the variation of reflection coefficient with thickness of the stratified layer.Case (3) may be of some importance as a first approximation to the conditions in the Heaviside layer.

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