Light Mixing and the Generation of the Second Harmonic in a Plasma in an External Magnetic Field

1965 ◽  
Vol 20 (6) ◽  
pp. 793-800 ◽  
Author(s):  
Wilhelm H. Kegel
Keyword(s):  
Magnetic Field ◽  
Electric Field ◽  
External Electric Field ◽  
Second Harmonic ◽  
Scattered Light ◽  
Homogeneous Magnetic Field ◽  
Density Fluctuations ◽  
Wave Number ◽  
The Difference ◽  
Electron Gyrofrequency

The theory of light scattering in a plasma is extended by including an external electric field (e.g. the field of a laser beam) in calculating the density fluctuations. It is shown that in the presence of a time constant homogeneous magnetic field there arise density fluctuations with the frequency and the wave number of the external electric field. Expansions of the general expressions are obtained for the case that the frequency is large compared to the electron gyrofrequency. The special case that the external electric field is a transverse wave is discussed in detail.The light of a second beam may be scattered by these forced density fluctuations. The scattered light has the sum and the difference frequency of the two light beams, i.e. light mixing occurs. In the framework of this theory the effect occurs only if the two beams are parallel. - If one considers the scattering of the same beam that forces the density fluctuations, the scattered light is the second harmonic

scholarly journals Inkohärente Lichtstreuung an Ladungsdichteschwankungen schwach ionisierter Plasmen in Magnetfeldern / Incoherent Scattering of Light from Charge-Density Fluctuations in Weakly Ionized Magnetoplasmas

1972 ◽  
Vol 27 (8-9) ◽  
pp. 1375-1376
Author(s):  
G. Klingenberg ◽  
E. W. Richter
Keyword(s):  
Magnetic Field ◽  
Spectral Density ◽  
Debye Length ◽  
Scattered Wave ◽  
Homogeneous Magnetic Field ◽  
Incoherent Scattering ◽  
Density Fluctuations ◽  
Electron Plasmas ◽  
Weakly Ionized ◽  
The Difference

Abstract The spectral density of light scattering from weakly ionized plasmas embedded in a homogeneous magnetic field Bis given by the work of WILLIAMS and CHAPPELL 1, 2 and KLINGENBERG 3 . The spectral density has been computed for electron plasmas and is analyzed for the case k ⊥B ( is the difference between the wave vectors of the incident wave and the scattered wave) in the regimes k D ≫ 1 and k D ≪ 1 (D is the Debye length).

Electric Field Effect on NQR in Ferroelectric Materials

1996 ◽  
Vol 51 (5-6) ◽  
pp. 646-650 ◽  
Author(s):  
Jae Kap Jung ◽  
Hae Jin Kim ◽  
Kee Tae Han ◽  
Sung Ho Choh
Keyword(s):  
Electric Field ◽  
External Electric Field ◽  
Field Effect ◽  
Ferroelectric Materials ◽  
Line Shift ◽  
Electric Field Effect ◽  
Ionic Crystals ◽  
Line Broadening ◽  
Nuclear Site ◽  
The Difference

Abstract The electric field effect on NQR in ferroelectric materials, 93Nb in LiNbO3 and 14N in NaNO2 and SC(NH2)2 , has been investigated at 77 K. In these crystals with single domain, only the line shift due to the external electric field was observed. In the case of NaNO2 powder and a crystal with multi-domains, line broadening was observed in the external electric field. These phenomena can be explained with the fact that the direction of spontaneous polarization in a domain is related to the direction of the applied electric field. The rate of the NQR line-shift due to the electric field is remarkably smaller in mostly ionic crystals, such as LiNbO3 and NaNO2 , than in a molecular crystal such as SC(NH2)2 . This is due to the strong ionic bonding in ionic crystals. Also, the difference of the Stark shift'between NaNO2 and SC(NH2)2 is discussed in terms of the local electric field and polarizability at the resonant nuclear site.

The propagation of plasma waves near multiples of the electron gyrofrequency

1971 ◽  
Vol 6 (3) ◽  
pp. 579-587 ◽  
Author(s):  
M. K. Andrews ◽  
M. T. C. Fang
Keyword(s):  
Magnetic Field ◽  
Refractive Index ◽  
Dispersion Relation ◽  
Plasma Waves ◽  
Wave Number ◽  
Ambient Plasma ◽  
Ambient Magnetic Field ◽  
Cyclotron Harmonics ◽  
Electron Gyrofrequency ◽  
Electrostatic Plasma Waves

The dispersion relation for electrostatic plasma waves propagating at frequencies near the electron cyclotron harmonics has been evaluated, and used to determine the refractive index curves for varying values of the angle θ between the k vector and the ambient magnetic field B0 in a warm magnetoplasma. It is shown that, under certain circumstances (which are defined), the (@, θ) curves have the characteristic ‘nose’ shapes that are necessary to provide a reflexion in the ambient plasma. Thus, the oblique echo reflexion mechanism (McAfee 1968, 1969a, b), which accounts for the appearance of the resonance signals or ‘spikes’ at the plasma and upper hybrid frequencies fN and fT on topside ionograms, may also be applied to the plasma waves propagating at frequencies near the electron gyro-harmonics. The relatively high damping that occurs for θ # 90° severely restricts the ranges of θ and wave-number k over which the reflexion mechanism applies. The restriction is such that the damping is severe for all values of θ when k is large, and for all values of θ outside a cone of ∽ 2° centred on θ = 90° when k is small.

Second-harmonic generation from (Si5Ge5)100 superlattices with an applied external electric field

1997 ◽  
Vol 71 (23) ◽  
pp. 3359-3361 ◽  
Author(s):  
Xinhui Zhang ◽  
Zhenghao Chen ◽  
Linzhen Xuan ◽  
Changsi Peng ◽  
Shaohua Pan ◽  
...  
Keyword(s):  
Electric Field ◽  
Second Harmonic Generation ◽  
External Electric Field ◽  
Harmonic Generation ◽  
Second Harmonic

scholarly journals Optical second harmonic generation in a ferromagnetic liquid crystal

Soft Matter ◽  
2019 ◽  
Vol 15 (43) ◽  
pp. 8758-8765
Author(s):  
Jure Brence ◽  
Luka Cmok ◽  
Nerea Sebastián ◽  
Alenka Mertelj ◽  
Darja Lisjak ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Liquid Crystal ◽  
Electric Field ◽  
Second Harmonic Generation ◽  
Harmonic Generation ◽  
Second Harmonic ◽  
Optical Second Harmonic Generation

SHG signal measured during electric field-induced and during magnetic field-induced reorientation.

Emission of extraordinary waves from an inhomogeous plasma

1995 ◽  
Vol 54 (3) ◽  
pp. 261-283
Author(s):  
R. Croci
Keyword(s):  
Magnetic Field ◽  
Electric Field ◽  
Analytical Form ◽  
Equilibrium Density ◽  
Fast Electrons ◽  
Plasma Slab ◽  
Model Equations ◽  
The Fourier Transform ◽  
Electron Gyrofrequency ◽  
Theoretical Results

The asymptotic solution of the system of Vlasov and Maxwell equations for a plasma slab with a given current distribution is derived for weak absorption and weak equilibrium density inhomogeneity, but without the usual restriction that the perpendicular wavelengths be larger than the Larmor radii of the thermal particles. The equilibrium magnetic field is homogeneous. No model equations or phenomenological assumptions are introduced, except that the interaction of the components of the electric field parallel and perpendicular to the equilibrium magnetic field (corresponding to the ordinary and extraordinary waves in a homogeneous plasma) has been neglected. The electric field in vacuum is determined by a condition on the analytical form of the Fourier transform of the field that must necessarily also apply to the exact solution. The example presented to illustrate the results considers the emission at the harmonics of the electron gyrofrequency of a population of fast electrons in a plasma with cold ions; the theoretical results are in a very good qualitative agreement with experiment.

Nonlinear Incoherent Light Scattering

1967 ◽  
Vol 22 (5) ◽  
pp. 662-670 ◽  
Author(s):  
A. Salat
Keyword(s):  
Magnetic Field ◽  
Light Scattering ◽  
Electromagnetic Radiation ◽  
Plasma Frequency ◽  
Density Fluctuations ◽  
Incoherent Light ◽  
Ion Density ◽  
Homogeneous Plasma ◽  
Coherent Beams ◽  
The Difference

Classical equations are used to calculate nonlinear incoherent light scattered from two coherent beams of electromagnetic radiation of different frequencies propagating in a homogeneous plasma without magnetic field. With a suitable choice of the difference frequency, enhanced light scattering occurs near the plasma frequency. In this case the frequency spectrum is mainly given by the thermal ion density fluctuations.

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