NONLINEAR PROPAGATION OF ELECTROMAGNETIC WAVES IN MAGNETOPLASMAS. II

1964 ◽  
Vol 42 (2) ◽  
pp. 349-363 ◽  
Author(s):  
Mahendra S. Sodha ◽  
Carl J. Palumbo
Keyword(s):  
Magnetic Field ◽  
Wave Equation ◽  
Electromagnetic Wave ◽  
Isotropic Medium ◽  
Electromagnetic Waves ◽  
Nonlinear Propagation ◽  
Complex Conductivity ◽  
Arbitrary Angle ◽  
Reflection And Refraction ◽  
The Magnetic Field

In this communication the authors have investigated the nonlinear propagation of an electromagnetic wave at an arbitrary angle to the direction of the magnetic field in a plasma. The authors have derived an expression for the complex conductivity tensor of a Lorentzian magnetoplasma, which is correct to terms involving the square of the amplitude of the electric vector. This expression, along with the wave equation, has been used to analyze two specific problems, viz. the propagation of an electromagnetic wave in an infinite magnetoplasma and reflection and refraction at the interface of a nonlinear magnetoplasma and a linear isotropic medium.

NONLINEAR PROPAGATION OF ELECTROMAGNETIC WAVES IN MAGNETOPLASMAS

1963 ◽  
Vol 41 (12) ◽  
pp. 2155-2165 ◽  
Author(s):  
Mahendra Singh Sodha ◽  
Carl J. Palumbo
Keyword(s):  
Magnetic Field ◽  
Wave Equation ◽  
Static Magnetic Field ◽  
Electromagnetic Waves ◽  
Second Order ◽  
Conductivity Tensor ◽  
Electric Vector ◽  
Nonlinear Propagation ◽  
Order Solution

In this communication the authors have derived an expression for the conductivity tensor of a Lorentzian plasma in the presence of a static magnetic field, which is correct to terms involving the square of the amplitude of the electric vector. This expression along with the wave equation has been used to obtain a second-order solution for the electric vector in the magnetoplasma. The phenomenon of demodulation of an amplitude-modulated wave has also been briefly discussed.

scholarly journals Nonorthogonality andκ-Dependence Eccentricity of Polarized Electromagnetic Waves in CPT-Even Lorentz Violation

2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Thiago Prudêncio ◽  
Humberto Belich
Keyword(s):  
Magnetic Field ◽  
Electromagnetic Wave ◽  
Electromagnetic Waves ◽  
Maxwell Equations ◽  
Lorentz Violation ◽  
Elliptical Polarization ◽  
Wave Fields ◽  
Lorentz Symmetry Breaking ◽  
Elliptically Polarized ◽  
The Magnetic Field

We discuss the modified Maxwell action of aKF-type Lorentz symmetry breaking theory and present a solution of Maxwell equations derived in the cases of linear and elliptically polarized electromagnetic waves in the vacuum of CPT-even Lorentz violation. We show in this case that the Lorentz violation has the effect of changing the amplitude of one component of the magnetic field, while leaving the electric field unchanged, leading to nonorthogonal propagation of electromagnetic fields and dependence of the eccentricity onκ-term. Further, we exhibit numerically the consequences of this effect in the cases of linear and elliptical polarization, in particular, the regimes of nonorthogonality of the electromagnetic wave fields and the eccentricity of the elliptical polarization of the magnetic field with dependence on theκ-term.

scholarly journals Oblique propagation of electromagnetic waves in a slowly-varying non-isotropic medium

1936 ◽  
Vol 155 (885) ◽  
pp. 235-257 ◽  
Keyword(s):  
Magnetic Field ◽  
Differential Equations ◽  
Electron Density ◽  
Isotropic Medium ◽  
Electromagnetic Waves ◽  
Mathematical Theory ◽  
Stratified Medium ◽  
Oblique Propagation ◽  
Isotropic Media ◽  
Mathematical Justification

The influence of the earth’s magnetic field on the propagation of wireless waves in the ionosphere has stimulated interest in the problem of the propagation of electromagnetic waves through a non-isotropic medium which is stratified in planes. Although the differential equations of such a medium have been elegantly deduced by Hartree,f it appears that no solution of them has yet been published for a medium which is both non-isotropic and non-homogeneous. Thus the work of Gans and Hartree dealt only with a stratified isotropic medium, while in the mathematical theory of crystal-optics the non-isotropic medium is always assumed to be homogeneous. In the same way Appleton’s magneto-ionic theory of propagation in an ionized medium under the influence of a magnetic field is confined to consideration of the “ characteristic ”waves which can be propagated through a homogeneous medium without change of form. In applying to stratified non-isotropic media these investigations concerning homogeneous non-isotropic media difficulty arises from the fact that the polarizations of the characteristic waves in general vary with the constitution of the medium, and it is not at all obvious that there exist waves which are propagated independently through the stratified medium and which are approximately characteristic at each stratum. The existence of such waves has usually been taken for granted, although for the ionosphere doubt has been cast upon this assumption by Appleton and Naismith, who suggest that we might “ expect the components ( i. e ., characteristic waves) to be continually splitting and resplitting”, even if the increase of electron density “ takes place slowly with increase of height”. It is clear that, until the existence of independently propagated approximately characteristic waves has been established, at any rate for a slowly-varying non-isotropic medium, no mathematical justification exists for applying Appleton's magnetoionic theory to the ionosphere. It is with the provision of this justification that we are primarily concerned in the present paper. This problem has been previously considered by Försterling and Lassen,f but we feel that their work does not carry conviction because they did not base their calculations on the differential equations for a non-homo-geneous medium, and were apparently unable to deal with the general case in which the characteristic polarizations vary with the constitution of the medium.

On the existence of compressional MHD oscillations in an inhomogeneous magnetoplasma

1990 ◽  
Vol 44 (2) ◽  
pp. 361-375 ◽  
Author(s):  
Andrew N. Wright
Keyword(s):  
Magnetic Field ◽  
Wave Equation ◽  
Density Distribution ◽  
Cold Plasma ◽  
Wave Equations ◽  
Perturbation Field ◽  
Plasma Density Distribution ◽  
Background Magnetic Field ◽  
Transverse Fields ◽  
The Magnetic Field

In a cold plasma the wave equation for solely compressional magnetic field perturbations appears to decouple in any surface orthogonal to the background magnetic field. However, the compressional fields in any two of these surfaces are related to each other by the condition that the perturbation field b be divergence-free. Hence the wave equations in these surfaces are not truly decoupled from one another. If the two solutions happen to be ‘matched’ (i.e. V.b = 0) then the medium may execute a solely compressional oscillation. If the two solutions are unmatched then transverse fields must evolve. We consider two classes of compressional solutions and derive a set of criteria for when the medium will be able to support pure compressional field oscillations. These criteria relate to the geometry of the magnetic field and the plasma density distribution. We present the conditions in such a manner that it is easy to see if a given magnetoplasma is able to executive either of the compressional solutions we investigate.

scholarly journals Radio Emission Model of a 'Typical' Pulsar

1987 ◽  
Vol 40 (6) ◽  
pp. 755 ◽  
Author(s):  
AZ Kazbegi ◽  
GZ Machabeli ◽  
G Melikidze
Keyword(s):  
Magnetic Field ◽  
Electromagnetic Waves ◽  
Emission Model ◽  
Radio Waves ◽  
Resonance Case ◽  
Pulsar Magnetosphere ◽  
Pulsar Emission ◽  
Dipole Magnetic Field ◽  
New Type ◽  
The Magnetic Field

The generation of radio waves in the plasma of the pulsar magnetosphere is considered taking into account the inhomogeneity of the dipole magnetic field. It is shown that the growth rate of the instability of the electromagnetic waves calculated in the non-resonance case turns out to be of the order of 1/ TO (where TO is the time of plasma escape from the light cylinder). However, the generation of electromagnetic waves from a new type Cherenkov resonance is possible, occurring when the particles have transverse velocities caused by the drift due to the inhomogeneity of the magnetic field. Estimates show that the development of this type of instability is possible only for pulsars with ages which exceed 104 yr. We make an attempt to explain some peculiarities of 'typical' pulsar emission on the basis of the model developed.

Linear conversion in a magnetized plasma with density gradient parallel to the magnetic field

1983 ◽  
Vol 30 (2) ◽  
pp. 179-192 ◽  
Author(s):  
E. Mjølhus
Keyword(s):  
Magnetic Field ◽  
Electromagnetic Wave ◽  
Density Gradient ◽  
Conversion Coefficient ◽  
Magnetized Plasma ◽  
Angle Of Incidence ◽  
Linear Conversion ◽  
The Magnetic Field

The problem of linear conversion of an ordinary polarized electromagnetic wave in a magnetized plasma with density gradient parallel to the magnetic field is considered. An expression for the conversion coefficient as a function of angle of incidence, WKB parameter and magnetic field is obtained. The magnetic field leads to a narrowing of the range of angles of incidence leading to linear conversion, compared with the unmagnetized case.

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.

Theory of Raman sidescatter from a magnetized plasma

1984 ◽  
Vol 32 (2) ◽  
pp. 331-346 ◽  
Author(s):  
H. C. Barr ◽  
T. J. M. Boyd ◽  
R. Rankin
Keyword(s):  
Magnetic Field ◽  
Electromagnetic Wave ◽  
Growth Rates ◽  
Scattered Light ◽  
Critical Density ◽  
Magnetized Plasma ◽  
Frequency Shifts ◽  
Wave Growth ◽  
Circularly Polarized ◽  
The Magnetic Field

The effects of a d.c. magnetic field on stimulated Raman sidescatter from laser-produced plasmas is studied. For exact sidescatter along the magnetic field, the Raman instability separates into two distinct decays in which the scattered light is either a right (RHCP) or left (LHCP) circularly polarized electromagnetic wave. Growth rates of the instabilities can be enhanced in the former case but are diminished in the latter. The magnetic field induced effects are greatest near the quarter critical density where frequency shifts can be especially significant, being equal to ± ¼Ωc for decay into RHCP and LHCP waves, respectively.

Whistler instability in plasmas with anisotropic and non-Maxwellian velocity distributions

1971 ◽  
Vol 6 (3) ◽  
pp. 449-456 ◽  
Author(s):  
Kai Fong Lee
Keyword(s):  
Magnetic Field ◽  
Electromagnetic Waves ◽  
Maxwell Equations ◽  
Transverse Velocity ◽  
Distribution Functions ◽  
Loss Cone ◽  
Circularly Polarized ◽  
Electron Plasmas ◽  
Thermal Spread ◽  
The Magnetic Field

The instability of right-handed, circularly polarized electromagnetic waves, propagating along an external magnetic field (whistler mode), is studied for electron plasmas with distribution functions peaked at some non-zero value of the transverse velocity. Based on the linearized Vlasov-Maxwell equations, the criteria for instability are given both for non-resonant instabilities arising from distribution functions with no thermal spread parallel to the magnetic field, and for resonant instabilities arising from distribution functions with Maxwellian dependence in the parallel velocities. It is found that, in general, the higher the average perpendicular energy, the more is the plasma susceptible to the whistler instability. These criteria are then applied to a sharply peaked ring distribution, and to loss-cone distributions of the Dory, Guest & Harris (1965) type.

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