Excitation of high-frequency waves with mixed polarization by streaming energetic electrons

1979 ◽  
Vol 22 (2) ◽  
pp. 277-288 ◽  
Author(s):  
L. C. Lee ◽  
C. S. Wu ◽  
H. P. Freund ◽  
D. Dillenburg ◽  
J. Goedert
Keyword(s):  
Magnetic Field ◽  
High Frequency ◽  
Plasma Frequency ◽  
Electron Plasma ◽  
Ion Dynamics ◽  
Electron Plasma Frequency ◽  
Ambient Magnetic Field ◽  
Suprathermal Electrons ◽  
High Frequency Waves ◽  
Thermal Background

The excitation of the slow extraordinary and electron whistler modes with frequencies in the vicinity of the electron plasma frequency is investigated for a plasma which is composed of thermal and suprathermal electrons. Ion dynamics are ignored. The suprathermal electrons are assumed to comprise a long, anisotropic tail parallel to the ambient magnetic field. Instability is found to occur via a relativistic, anomalous gyroresonance with the suprathermal electrons, and to excite waves with frequencies above and below the electron plasma frequency. Landau and cyclotron damping due to the thermal background is included in the treatment.

Anomalous high-frequency conductivity of a turbulent plasma

1968 ◽  
Vol 2 (3) ◽  
pp. 465-482 ◽  
Author(s):  
B. Bertotti ◽  
O. De Barbieri
Keyword(s):  
High Frequency ◽  
Plasma Frequency ◽  
Electron Plasma ◽  
Turbulent Plasma ◽  
Distribution Functions ◽  
Conductivity Tensor ◽  
Three Dimensional Model ◽  
Electron Plasma Frequency ◽  
Wide Range ◽  
Anisotropic Character

In this work we evaluate the anomalous high-frequency conductivity arising from particle—wave interactions in a multi-species turbulent plasma with no external magnetic field. The calculation is made by using the full three-dimensional model of the quasi-linear theory of plasma turbulence for a wide range of frequencies embracing the electron plasma frequency. It is found that the conductivity tensor is anisotropic and slowly time dependent; this reflects the slow time dependence and the anisotropic character of the distribution functions of the velocities of the particles. It is also found that there is a very narrow range of frequencies (just above the electron plasma frequency) for which the components of the conductivity tensor are negative. The particular case of the two- stream instability is examined in detail. The anisotropic character of the components of the conductivity tensor and their dependence on the frequency of the external field is studied. Finally some possible means for an experimental check of our calculations are suggested.

scholarly journals Excitation of electron acoustic waves near the electron plasma frequency and at twice the plasma frequency

2000 ◽  
Vol 105 (A6) ◽  
pp. 12919-12927 ◽  
Author(s):  
D. Schriver ◽  
M. Ashour-Abdalla ◽  
V. Sotnikov ◽  
P. Hellinger ◽  
V. Fiala ◽  
...  
Keyword(s):  
Acoustic Waves ◽  
Plasma Frequency ◽  
Electron Plasma ◽  
Electron Plasma Frequency ◽  
Electron Acoustic Waves ◽  
Electron Acoustic

Magnetic stabilization of transverse plasma instabilitiest

1971 ◽  
Vol 5 (3) ◽  
pp. 467-474 ◽  
Author(s):  
B. Buti ◽  
G. S. Lakhina
Keyword(s):  
Magnetic Field ◽  
Growth Rate ◽  
Cyclotron Frequency ◽  
Plasma Frequency ◽  
Electron Plasma ◽  
Wave Number ◽  
Uniform External Magnetic Field ◽  
Magnetic Stabilization ◽  
Streaming Velocity ◽  
The Magnetic Field

Waves, propagating transverse to the direction of the streaming of a plasma in the presence of a uniform external magnetic field, are unstable if the streaming exceeds a certain minimum value. The magnetic field reduces the growth rate of this instability, and also increases the value of the minimum streaming velocity, above which the system is unstable. The thermal motions in the plasma, however, tend to stabilize the system if the magnetic field is weak (i.e. , Ω being the electron cyclotron frequency, k the characteristic wave-number, and Vt the thermal velocity); but, in case of strong magnetic field (i.e. ), they increase the growth rate, provided (ωp being the electron plasma frequency).

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.

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