Optical Mixing in a Magnetized Plasma

1971 ◽  
Vol 49 (16) ◽  
pp. 2187-2193 ◽  
Author(s):  
J. Meyer ◽  
B. Stansfield
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Spectral Density ◽  
Electromagnetic Waves ◽  
Basic Assumption ◽  
Magnetized Plasma ◽  
Ion Motion ◽  
Resonance Frequencies ◽  
Optical Mixing ◽  
The Magnetic Field

The nonlinear interactions of two electromagnetic waves resulting in the excitation of electrostatic oscillations in a magnetized homogeneous plasma are studied. A general expression for the spectral density of the induced fluctuations is derived which includes the effect of the ion motion and an externally applied uniform magnetic field. One basic assumption made is that the frequencies of the electromagnetic waves are much larger than any of the plasma resonance frequencies. Numerical calculations are carried out for the specific case where the induced k vector is parallel to the external magnetic field and the results are presented in a series of graphs. The effect of the ion motion for this case is discussed in detail. Some aspects of the case where the induced k vector is perpendicular to the magnetic field are also discussed. It is found that both—the ion motion and an external magnetic field—can significantly influence the spectral density of the fluctuations.

Schwingung eines Plasmazylinders in einem axialen Magnetfeld II

1960 ◽  
Vol 15 (3) ◽  
pp. 220-226 ◽  
Author(s):  
Klaus Körper
Keyword(s):  
Magnetic Field ◽  
Refractive Index ◽  
External Magnetic Field ◽  
Field Strength ◽  
Axial Magnetic Field ◽  
Surface Current ◽  
The Other ◽  
Plasma Cylinder ◽  
Resonance Frequencies ◽  
The Magnetic Field

Radial oscillations are excited in a homogeneous infinite plasma cylinder in a homogeneous axial magnetic field by a surface current which is homogeneous in the axial and azimuthal directions. The modes of oscillations corresponding to the axial and azimuthal components of current are not coupled, and so they may be analysed separately. The magnetic field in the plasma and vacuum is obtained, and the indices of refraction for both types of oscillations are discussed thoroughly. When the currents are parallel to the external magnetic field, the oscillations are characterized by the refractive index of Eccles. On the other hand, when the current is perpendicular to the magnetic field two resonance frequencies exist, which depend on the density of the plasma and the magnetic field strength. — In the latter case the radial characteristic oscillations of the plasma cylinder in an external magnetic field are considered.

scholarly journals Structure of nonlinear whistlers moving through plasma at an angle to the magnetic field

2018 ◽  
Vol 4 (1) ◽  
pp. 25-28
Author(s):  
Геннадий Кичигин ◽  
Gennadiy Kichigin
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Numerical Solutions ◽  
Field Vector ◽  
Magnetized Plasma ◽  
Small Scale ◽  
Motion Direction ◽  
Magnetic Field Change ◽  
The Magnetic Field ◽  
Two Fluid

The paper presents solutions of two-fluid magnetic hydrodynamics equations describing small-scale fast magnetosonic stable waves — nonlinear whist-lers moving in a cold magnetized plasma at an angle α to the external magnetic field. At the fixed angle α, the Alfvén Mach number of the whistlers has a narrow range of allowed values. It has been found that when passing from extremely small Mach numbers to ex-tremely large ones, amplitudes and spatial structure of wave velocity components and whistler magnetic field change significantly. The range of angles of the motion direction of whistlers with respect to direction of the the external magnetic field vector is determined. Within this range, the obtained approximate analytical and numerical solutions are in satisfactory agreement.

Electromagnetic instabilities in non-uniform anisotropic plasmas

1973 ◽  
Vol 10 (2) ◽  
pp. 249-263 ◽  
Author(s):  
B. Butt ◽  
G. S. Lakhina
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Electromagnetic Waves ◽  
Temperature Gradients ◽  
Anisotropic Plasma ◽  
Field Gradients ◽  
Cyclotron Instability ◽  
Magnetic Field Gradients ◽  
Resonant Electron ◽  
The Magnetic Field

Electromagnetic waves propagating perpendicular to an external magnetic field in a non-uniform anisotropic plasma can become unstable due to the excitation of either resonant ion instability or resonant electron instability. The former instability can exist in the absence of both the temperture anisotropy and the temperature gradients, whereas for the excitation of resonant electron instability the presence of at least one of them is necessary. An off-resonance drift cyclotron instability can also get excited if the temperature gradients are much stronger than the magnetic field gradients.

Convective laser filamentation instability in magnetized plasma

2014 ◽  
Vol 92 (6) ◽  
pp. 504-508 ◽  
Author(s):  
M.S. Bawa’aneh ◽  
Ghada Assayed ◽  
M.R. Said ◽  
S. Al-Awfi
Keyword(s):  
Magnetic Field ◽  
Electromagnetic Waves ◽  
Amplification Factor ◽  
Magnetized Plasma ◽  
Governing Equations ◽  
Equilibrium Plasma ◽  
Dc Magnetic Field ◽  
Density Values ◽  
Filamentation Instability ◽  
The Magnetic Field

The convective amplification of filamentation instability (FI) of electromagnetic waves traveling along the density ramp of a magnetized plasma is investigated. The generalized amplification factor of the instability in the presence of a DC–magnetic field is derived by obtaining the governing equations of the instability and using the slow-coupling technique to obtain an analytical expression for the amplification factor in weakly magnetized plasma. The result shows enhancement of the convective FI gain by the magnetic field, where the enhancement is stronger for lower equilibrium plasma density values.

Electrostatic waves potential at the plasma and upper-hybrid resonances

1981 ◽  
Vol 25 (2) ◽  
pp. 239-254 ◽  
Author(s):  
J. Thiel ◽  
R. Debrie
Keyword(s):  
Magnetic Field ◽  
Kinetic Theory ◽  
Dispersion Equation ◽  
Cyclotron Frequency ◽  
Plasma Frequency ◽  
Electrostatic Waves ◽  
Ion Motion ◽  
Hybrid Resonance ◽  
Resonance Frequencies ◽  
The Magnetic Field

The potential created by an infinitesimal alternating dipole in a Maxwellian magnetoplasma is computed numerically at the plasma and upper-hybrid resonance frequencies when the latter extends from one to three times the electron cyclotron frequency. A linear full kinetic theory is used for a homogeneous magnetoplasma for which the forced ion motion and the collisions are neglected. The integral which gives the potential is evaluated by using the least-damping- roots (LDR) approximation, i.e. by neglecting the higher-order roots of the dispersion equation for electrostatic waves. Some characteristic potential patterns of dipoles parallel and perpendicular to the magnetic field are computed and comparisons with analytical results previously published are made. The numerical and analytical patterns are similar only at the plasma frequency when the dipole is parallel to the magnetic field.

Cross-field plasma acceleration and potential formation induced by electromagnetic waves in a magnetized plasma

2001 ◽  
Vol 66 (3) ◽  
pp. 143-155 ◽  
Author(s):  
R. SUGAYA
Keyword(s):  
Magnetic Field ◽  
Particle Acceleration ◽  
Electric Field ◽  
Electromagnetic Waves ◽  
Collisionless Plasma ◽  
Magnetized Plasma ◽  
Propagating Waves ◽  
Potential Formation ◽  
Dynamo Effect ◽  
The Magnetic Field

A single-particle theory is developed to investigate particle acceleration along and across a magnetic field and the generation of an electric field transverse to the magnetic field induced by electromagnetic waves in a magnetized plasma. The almost perpendicularly propagating waves accelerate particles via their Landau and cyclotron damping, and the ratio of parallel and perpendicular drift velocities vs∥/vd can be proved to be proportional to k∥/k⊥. Simultaneously, an intense cross-field electric field E0 = B0×vd/c is generated via the dynamo effect owing to perpendicular particle acceleration to satisfy the generalized Ohm’s law. This means that this cross-field particle drift in a collisionless plasma is identical to E×B drift. It is verified that the transport equations obtained are exactly equivalent to those derived from the θ-dependent quasilinear velocity-space diffusion equation obtained from the Vlasov–Maxwell equations.

scholarly journals Structure of nonlinear whistlers moving through plasma at an angle to the magnetic field

2018 ◽  
Vol 4 (1) ◽  
pp. 28-32 ◽  
Author(s):  
Геннадий Кичигин ◽  
Gennadiy Kichigin
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Numerical Solutions ◽  
Field Vector ◽  
Magnetized Plasma ◽  
Small Scale ◽  
Motion Direction ◽  
Magnetic Field Change ◽  
The Magnetic Field ◽  
Two Fluid

The paper presents solutions of two-fluid magnetic hydrodynamics equations describing small-scale fast magnetosonic stable waves — nonlinear whist-lers moving in a cold magnetized plasma at an angle α to the external magnetic field. At the fixed angle α, the Alfvén Mach number of the whistlers has a narrow range of allowed values. It has been found that when passing from extremely small Mach numbers to ex-tremely large ones, amplitudes and spatial structure of wave velocity components and whistler magnetic field change significantly. The range of angles of the motion direction of whistlers with respect to direction of the the external magnetic field vector is determined. Within this range, the obtained approximate analytical and numerical solutions are in satisfactory agreement.

Stimulated backscattering of electromagnetic waves from ion–ion hybrid waves in a magnetized plasma

1975 ◽  
Vol 14 (2) ◽  
pp. 245-253 ◽  
Author(s):  
Kai Fong Lee
Keyword(s):  
Magnetic Field ◽  
Electromagnetic Waves ◽  
Magnetized Plasma ◽  
Threshold Power ◽  
Lower Hybrid ◽  
Stimulated Scattering ◽  
Electrostatic Waves ◽  
Hybrid Frequency ◽  
Hybrid Waves ◽  
The Magnetic Field

In a high-density magnetized plasma composed of two ion species of different charge-to-mass ratios, electrostatic waves propagating across the magnetic field exhibit a resonance at the Buchsbaum or ion-ion hybrid frequency, in addition to the resonances at the upper and lower hybrid frequencies. In this paper, the possibility of stimulated scattering of electromagnetic waves incident normal to the magnetic field from electrostatic waves at the ion-ion hybrid frequency is investigated. Based on the cold-plasma equations, it is found that such a process is theoretically possible. Formulas for the threshold power and growth rate are obtained, which show that the threshold power is much greater, and the growth rate much less, than those of stimulated scattering from upper and lower hybrid waves.

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