Interaction of a highly relativistic helical electron stream and a cold magnetoactive plasma

1969 ◽  
Vol 47 (2) ◽  
pp. 161-177 ◽  
Author(s):  
P. C. W. Fung
Keyword(s):  
Magnetic Field ◽  
Growth Rate ◽  
Static Magnetic Field ◽  
Pitch Angle ◽  
Magnetoactive Plasma ◽  
Electron Stream ◽  
Amplification Rate ◽  
Wave Normal ◽  
Normal Angle ◽  
Temporal Growth Rate

When a nearly monoenergetic relativistic electron stream is gyrating along a cold magnetoactive plasma with general pitch angle Φ (defined as the angle between the static magnetic field of the plasma and the momentum of a particle in the stream), the system is shown to be radiatively unstable with respect to synchrotron radiation. Using the classical kinetic approach, the temporal growth rate is derived for general wave-normal angle θ (defined as the angle between the static magnetic field and wave vector k). Deducing the spatial amplification rate from the temporal growth rate, the result obtained here is shown to be identical with that obtained from the Einstein-coefficients approach deduced by Fung earlier.

scholarly journals Excitation Of Cyclotron Electromagnetic Waves In A Magnetoactive Plasma By A Stream Of Charged Particles, Including Temperature Effects In The Stream

1966 ◽  
Vol 19 (4) ◽  
pp. 489 ◽  
Keyword(s):  
Magnetic Field ◽  
Growth Rate ◽  
Charged Particle ◽  
Temperature Effects ◽  
Electromagnetic Waves ◽  
Charged Particles ◽  
Magnetoactive Plasma ◽  
Particle Stream ◽  
Wave Normal ◽  
Normal Angle

The dispersion equation for cyclotron electromagnetic waves in a system comprising a charged particle stream injected at an angle to the static magnetic field of a magnetoactive plasma is derived for a general wave�normal angle () when the temperature of the stream has been taken into account. The expression for the growth rate is derived in general for all cyclotron waves.

On the instability of synchrotron radiation

1968 ◽  
Vol 46 (9) ◽  
pp. 1073-1081 ◽  
Author(s):  
P. C. W. Fung
Keyword(s):  
Growth Rate ◽  
Synchrotron Radiation ◽  
Magnetoactive Plasma ◽  
Kinetic Approach ◽  
Relativistic Electrons ◽  
Wave Normal ◽  
Quantum Treatment ◽  
Normal Angle

In a system of isotropic relativistic electrons which is embedded in a cold ambient magnetoactive plasma, the growth rate of synchrotron radiation at wave normal angle θ = 90° is derived by means of the classical kinetic approach. It is shown that the result is identical with that obtained from the quantum treatment. Two errors occurring in the literature of synchrotron radiation are pointed out. The growth rate is computed for the case of monoenergetic electrons as an example.

Filamentation instability in a collisional magnetoplasma with thermal conduction

2009 ◽  
Vol 75 (4) ◽  
pp. 563-573 ◽  
Author(s):  
MAHENDRA SINGH SODHA ◽  
MOHAMMAD FAISAL
Keyword(s):  
Magnetic Field ◽  
Growth Rate ◽  
Static Magnetic Field ◽  
Power Loss ◽  
Thermal Conduction ◽  
Ohmic Heating ◽  
Wave Number ◽  
Main Beam ◽  
Rate Of Growth ◽  
Filamentation Instability

AbstractThis paper presents an analysis of the spatial growth of a transverse instability, corresponding to the propagation of an electromagnetic beam, with uniform irradiance along the wavefront in a collisional plasma, along the direction of a static magnetic field; expressions have been derived for the rate of growth, the maximum value of the rate of growth and the corresponding value of the wave number of the instability. The instability arises on account of the ejection of electrons from regions where the irradiance of the perturbation is large. The energy balance of the electrons taking into account ohmic heating and the power loss of electrons on account of (i) collisions with ions and neutral species and (ii) thermal conduction has been taken into account for the evaluation of the perturbation in electron temperature, which determines the subsequent growth of the instability. Further, the relationship between the electron density and temperature, as obtained from the kinetic theory, has been used. The filamentation instability becomes enhanced with the increase of the static magnetic field for the extraordinary mode while the reverse is true for the ordinary mode. Dependence of growth rate on irradiance of the main beam, magnetic field and a parameter proportional to the ratio of power loss of electrons by conduction to that by collisions has been numerically studied and illustrated by figures. The dependence of the maximum growth rate and the corresponding optimum value of the wave number of the instability on the irradiance of the main beam has also been studied. The paper concludes with a discussion of the numerical results, so obtained.

Oblique whistler-mode propagation in a hot anisotropic plasma

1982 ◽  
Vol 27 (2) ◽  
pp. 199-204 ◽  
Author(s):  
S. S. Sazhin ◽  
E. M. Sazhina
Keyword(s):  
Magnetic Field ◽  
Dispersion Relation ◽  
Plasma Temperature ◽  
Anisotropic Plasma ◽  
Mode Propagation ◽  
Whistler Mode ◽  
Energy Focusing ◽  
Wave Normal ◽  
The Magnetic Field ◽  
Normal Angle

An approximate dispersion relation is obtained for quasi-longitudinal whistler mode propagation in the hot anisotropic plasma. The influence of plasma temperature and anisotropy on whistler energy focusing along the magnetic field and whistler trapping in the magnetospheric ducts are considered for the case when the whistler wave normal angle is not equal to zero.

Stimulated backscattering of electromagnetic ordinary waves from extraordinary waves below the upper hybrid frequency

1979 ◽  
Vol 21 (1) ◽  
pp. 97-106 ◽  
Author(s):  
Behrooz Maraghechi ◽  
Joseph E. Willett
Keyword(s):  
Magnetic Field ◽  
Growth Rate ◽  
Static Magnetic Field ◽  
Inhomogeneous Plasma ◽  
Extraordinary Wave ◽  
Threshold Power ◽  
Ordinary Wave ◽  
Homogeneous Plasma ◽  
Parametric Decay ◽  
Hybrid Frequency

The parametric decay of an intense electromagnetic ordinary wave, propagating perpendicular to a uniform static magnetic field, into an extraordinary wave and a backscattered ordinary wave is investigated. Formulae are derived for the growth rate and threshold power associated with the instability in a homogeneous plasma. An analysis of the spatial amplification of the decay waves in an inhomogeneous plasma is presented. The effects of the uniform static magnetic field on the backscattering in both homogeneous and inhomogeneous plasmas are studied numerically.

scholarly journals Improvement of SiC Crystal Growth Rate and Uniformity via Top-Seeded Solution Growth under External Static Magnetic Field: A Numerical Investigation

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 651
Author(s):  
Minh-Tan Ha ◽  
Le Van Lich ◽  
Yun-Ji Shin ◽  
Si-Young Bae ◽  
Myung-Hyun Lee ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Growth Rate ◽  
Fluid Flow ◽  
Crystal Growth ◽  
Static Magnetic Field ◽  
Crystal Surface ◽  
Solution Growth ◽  
Helmholtz Coils ◽  
External Static Magnetic Field ◽  
Top Seeded Solution Growth

Silicon carbide (SiC) is an ideal material for high-power and high-performance electronic applications. Top-seeded solution growth (TSSG) is considered as a potential method for bulk growth of high-quality SiC single crystals from the liquid phase source material. The crystal growth performance, such as growth rate and uniformity, is driven by the fluid flow and constitutional flux in the solution. In this study, we numerically investigate the contribution of the external static magnetic field generated by Helmholtz coils to the fluid flow in the silicon melt. Depending on the setup of the Helmholtz coils, four static magnetic field distributions are available, namely, uniform vertical upward/downward and vertical/horizontal cusp. Based on the calculated carbon flux coming to the crystal surface, the vertical downward magnetic field proved its ability to enhance the growth rate as well as the uniformity of the grown crystal.

Intermediate Phase Growth of Mg-Al Diffusion Couple under a Strong Static Magnetic Field

2007 ◽  
Vol 546-549 ◽  
pp. 491-494 ◽  
Author(s):  
Jie Dong ◽  
Z.F. Li ◽  
Xiao Qin Zeng ◽  
Wen Jiang Ding
Keyword(s):  
Magnetic Field ◽  
Growth Rate ◽  
Diffusion Couple ◽  
Static Magnetic Field ◽  
Intermediate Phase ◽  
Thickness Measurement ◽  
Magnetic Field Direction ◽  
Diffusion Couples ◽  
Phase Growth ◽  
Intermediate Phases

Intermediate phase growth in Mg-Al diffusion couples were studied with different intensity of a strong static magnetic field from 0 to 10 Tesla. Thickness measurement of the intermediate phases (Mg17Al12 and Al3Mg2) shows that with the increasing of magnetic field intensity, the growth rate of both intermediate phases is retarded. The decrease of the phase growth rate is ascribed to the suppressed Al, Mg atom interdiffusion in the diffusion couple under the static magnetic field. It is also found that the orientation relationship between couple interface and magnetic field direction has no influence on the growth of intermediate phases.

scholarly journals Brillouin-shifted third-harmonic backscattering of laser in a magnetized plasma

2015 ◽  
Vol 33 (1) ◽  
pp. 97-102 ◽  
Author(s):  
Alireza Paknezhad
Keyword(s):  
Magnetic Field ◽  
Growth Rate ◽  
Static Magnetic Field ◽  
Maximum Growth ◽  
Maximum Growth Rate ◽  
Magnetized Plasma ◽  
Third Harmonic ◽  
Coupled Equations ◽  
Relativistic Mass ◽  
Weakly Coupled

AbstractThird-harmonic Brillouin backscattering (3HBBS) instability is investigated in the interaction of a picosecond extraordinary laser pulse with a homogeneous transversely magnetized underdense plasma. Nonlinear coupled equations that describe the instability are derived and solved for a weakly coupled regime to find the maximum growth rate. The nonlinearity arises through the combined effect of relativistic mass increase, static magnetic field, and ponderomotive acceleration of plasma electrons. The growth rate is found to decrease as the static magnetic field increases. It also increases by increasing both plasma density and laser intensity. It is also established that the growth rate of 3HBBS instability in a magnetized plasma is lower than that of fundamental Brillouin backscattering instability.

scholarly journals Brillouin backward scattering in the nonlinear interaction of a short-pulse laser with an underdense transversely magnetized plasma

2013 ◽  
Vol 31 (2) ◽  
pp. 313-319 ◽  
Author(s):  
Alireza Paknezhad
Keyword(s):  
Magnetic Field ◽  
Growth Rate ◽  
External Magnetic Field ◽  
Short Pulse ◽  
Propagation Direction ◽  
Magnetized Plasma ◽  
Third Order ◽  
Short Pulse Laser ◽  
Linearly Polarized ◽  
Temporal Growth Rate

AbstractBrillouin backward scattering is investigated in the interaction of linearly polarized short laser pulse with a homogenous underdense transversely magnetized plasma by taking into account the relativistic and nonlinearity effects up to third order. The plasma is embedded in a uniform magnetic field perpendicular to both of propagation direction and electric vector of the radiation field. Temporal growth rate of instability is calculated by using of the nonlinear wave equation. Results are significantly different in comparison with lower order computations. The growth rate of Brillouin backward instability shows a decrease due to the presence of external magnetic field, while relativistic and higher order nonlinearities due to the external magnetic field, give rise the Brillouin backward scattering instability.

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