Wave propagation in a moving plasma: motion and wave propagation normal to the magnetic field

1973 ◽  
Vol 10 (2) ◽  
pp. 197-202
Author(s):  
D. N. Srivastava
Keyword(s):  
Magnetic Field ◽  
Wave Propagation ◽  
Dispersion Relation ◽  
Electron Plasma ◽  
Extraordinary Wave ◽  
Ordinary Wave ◽  
Phase Velocities ◽  
Small Phase ◽  
Moving Plasma ◽  
The Magnetic Field

The dispersion relation for a collisionless moving electron plasma when the directions of motion and wave propagation are normal to the magnetic field is analyzed. It is shown that the ordinary wave remains unaffected, but the extraordinary wave shows a different behaviour, especially at small phase velocities. It has different cut-off frequencies, propagates for all frequencies from zero to infinity, changes the sense of polarization accompanied by anomalous dispersion and does not show any resonance.

Wave propagation in a moving plasma. Part 1. Wave propagation normal to the magnetic field and motion of the plasma along the magnetic field

1974 ◽  
Vol 11 (3) ◽  
pp. 389-395 ◽  
Author(s):  
D. N. Srivastava
Keyword(s):  
Magnetic Field ◽  
Wave Propagation ◽  
Dispersion Relation ◽  
Magnetic Fields ◽  
Plasma Frequency ◽  
Electron Plasma ◽  
Ordinary Wave ◽  
Moving Plasma ◽  
The Magnetic Field

The dispersion relation for a collisionless moving electron plasma, when the direction of motion is along the magnetic field, and that of the wave propagation normal to the magnetic field, is analysed. It is shown that in small magnetic fields the ordinary wave develops a new band of backward waves below the plasma frequency. When the frequency of the wave is higher than the plasma frequency, the effect of the motion of the plasma is identical to a deviation of the direction of propagation.

Comparison of wave propagation in the stationary and moving plasma: motion and wave propagation along the magnetic field

1972 ◽  
Vol 8 (2) ◽  
pp. 127-135 ◽  
Author(s):  
D. N. Srivastava
Keyword(s):  
Magnetic Field ◽  
Refractive Index ◽  
Wave Propagation ◽  
Cyclotron Resonance ◽  
Plasma Velocity ◽  
Phase Velocities ◽  
Large Phase ◽  
Moving Plasma ◽  
Independent Variable ◽  
The Magnetic Field

The three important aspects of wave propagation in a stationary and a moving plasma (namely frequency, polarization and dispersion) are compared, taking the phase refractive index of the wave as the independent variable. Wave propagation and the motion of the plasma are taken to be along the magnetic field. The plasma is assumed to consist of one species only, and the effect of collisions is neglected. Wave propagation in a moving plasma has been shown to possess several important features, such as the absence of cyclotron resonance, reversal of the sense of polarization when the phase velocity becomes equal to the plasma velocity, and the existence of backward waves for very small and very large phase velocities.

Effect of spatially uniform external periodic magnetic field on wave propagation through a hot electron plasma

1971 ◽  
Vol 5 (2) ◽  
pp. 151-159 ◽  
Author(s):  
K. P. Das
Keyword(s):  
Magnetic Field ◽  
Wave Propagation ◽  
Dispersion Relation ◽  
Electron Plasma ◽  
Hydrodynamic Equations ◽  
Hot Electron ◽  
Periodic Magnetic Field ◽  
Excitation Conditions

Starting from hydrodynamic equations, a dispersion relation is obtained for wave propagation through a hot electron plasma perpendicular to a spatially uniform external periodic magnetic field, B0 cos ω0t, and several excitation conditions are deduced.

Stability of Viscous Rotating Gravitating Streams in a Magnetic Field

2006 ◽  
Vol 61 (5-6) ◽  
pp. 258-262
Author(s):  
Prem Kumar Bhatia ◽  
Ravi Prakash Mathur
Keyword(s):  
Magnetic Field ◽  
Wave Propagation ◽  
Dispersion Relation ◽  
Horizontal Magnetic Field ◽  
The Stability ◽  
The Magnetic Field ◽  
Perturbation Equations

We have studied the stability of two superposed viscous compressible gravitating streams rotating about an axis perpendicular to the direction of a horizontal magnetic field. For wave propagation parallel to the direction of the magnetic field the dispersion relation is derived by solving the linearized perturbation equations. Both the viscosity and rotation are found to suppress the instability of the system

Linear stability of Vlasov–Poisson electron plasma in crossed fields. Perturbations propagating parallel to the magnetic field

1988 ◽  
Vol 40 (3) ◽  
pp. 535-543 ◽  
Author(s):  
Hee-Jae Lee ◽  
D. J. Kaup ◽  
Gary E. Thomas
Keyword(s):  
Magnetic Field ◽  
Temperature Distribution ◽  
Dispersion Relation ◽  
Linear Stability ◽  
Electron Density ◽  
Electron Plasma ◽  
Eigenvalue Equation ◽  
Planar Magnetron ◽  
The Magnetic Field

It is shown that electrostatic Vlasov–Poisson perturbations that propagate parallel to the magnetic field in a planar magnetron are stable for both an isotropic and also for a particular anisotropic (Ty = 3Tx) temperature distribution. The inhomogeneity of the electron density is fully incorporated in the analysis. The proof makes use of only the dispersion relation of Trivelpiece–Gould type, without actually solving the eigenvalue equation. These results suggest, not unexpectedly, that these modes should be stable for all such anisotropic velocity distributions.

Wave propagation in a moving plasma. Part 2. Wave propagation along, and plasma motion normal to, the magnetic field

1974 ◽  
Vol 12 (2) ◽  
pp. 271-278
Author(s):  
D. N. Srivastava
Keyword(s):  
Magnetic Field ◽  
Wave Propagation ◽  
Magnetic Fields ◽  
Low Frequency ◽  
Wave Band ◽  
Weak Magnetic Fields ◽  
Moving Plasma ◽  
The One ◽  
The Right ◽  
The Magnetic Field

This paper analyses the dispersion relation for a collisionless moving electron plasma, when the direction of motion is normal to the magnetic field and that of the wave propagation along the magnetic field. It is shown that, in strong magnetic fields, the one continuous allowed band of the left-handed wave (of the stationary plasma) splits into two, and the right-handed wave shows a second resonance besides the cyclotron resonance. In weak magnetic fields, the lefthanded wave develops a backward wave band, which shows resonance at its low frequency edge, and the right-handed wave also develops an extra band of propagation. The effect of the motion of the plasma, on waves of frequency much lower than the plasma frequency, is identical to a doppler shift, but, on those of frequency much higher than that, is negligible.

Frequency doubling of extraordinary wave

1986 ◽  
Vol 35 (1) ◽  
pp. 125-132 ◽  
Author(s):  
V. M. Čadež ◽  
D. Jovanović
Keyword(s):  
Magnetic Field ◽  
Pump Wave ◽  
Second Harmonic ◽  
Frequency Doubling ◽  
Electron Plasma ◽  
Extraordinary Wave ◽  
Slab Thickness ◽  
Phase Synchronism ◽  
Efficiency Parameter ◽  
The Magnetic Field

Second-harmonic generation of an extraordinary wave is investigated in the domain of phase synchronism with the pump wave. The conversion efficiency parameter is calculated for various values of the magnetic field, electron plasma density, angle of propagation and slab thickness.

scholarly journals Inferring the chromospheric magnetic topology through waves

2007 ◽  
Vol 3 (S247) ◽  
pp. 78-81
Author(s):  
S. S. Hasan ◽  
O. Steiner ◽  
A. van Ballegooijen
Keyword(s):  
Magnetic Field ◽  
Wave Propagation ◽  
Energy Density ◽  
Acoustic Wave ◽  
Acoustic Waves ◽  
Phase Speed ◽  
Time Correlation ◽  
Propagation Time ◽  
Fast Mode ◽  
The Magnetic Field

AbstractThe aim of this work is to examine the hypothesis that the wave propagation time in the solar atmosphere can be used to infer the magnetic topography in the chromosphere as suggested by Finsterle et al. (2004). We do this by using an extension of our earlier 2-D MHD work on the interaction of acoustic waves with a flux sheet. It is well known that these waves undergo mode transformation due to the presence of a magnetic field which is particularly effective at the surface of equipartition between the magnetic and thermal energy density, the β = 1 surface. This transformation depends sensitively on the angle between the wave vector and the local field direction. At the β = 1 interface, the wave that enters the flux sheet, (essentially the fast mode) has a higher phase speed than the incident acoustic wave. A time correlation between wave motions in the non-magnetic and magnetic regions could therefore provide a powerful diagnostic for mapping the magnetic field in the chromospheric network.

scholarly journals Magnetic Rayleigh–Taylor instability at a contact discontinuity with an oblique magnetic field

2020 ◽  
Vol 634 ◽  
pp. A96
Author(s):  
E. Vickers ◽  
I. Ballai ◽  
R. Erdélyi
Keyword(s):  
Magnetic Field ◽  
Growth Rate ◽  
Dispersion Relation ◽  
Contact Discontinuity ◽  
Homogeneous Magnetic Field ◽  
Taylor Instability ◽  
Wide Range ◽  
Rayleigh Taylor Instability ◽  
The Magnetic Field ◽  
Theoretical Results

Aims. We investigate the nature of the magnetic Rayleigh–Taylor instability at a density interface that is permeated by an oblique homogeneous magnetic field in an incompressible limit. Methods. Using the system of linearised ideal incompressible magnetohydrodynamics equations, we derive the dispersion relation for perturbations of the contact discontinuity by imposing the necessary continuity conditions at the interface. The imaginary part of the frequency describes the growth rate of waves due to instability. The growth rate of waves is studied by numerically solving the dispersion relation. Results. The critical wavenumber at which waves become unstable, which is present for a parallel magnetic field, disappears because the magnetic field is inclined. Instead, waves are shown to be unstable for all wavenumbers. Theoretical results are applied to diagnose the structure of the magnetic field in prominence threads. When we apply our theoretical results to observed waves in prominence plumes, we obtain a wide range of field inclination angles, from 0.5° up to 30°. These results highlight the diagnostic possibilities that our study offers.

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