Excitation of VLF quasi-electrostatic oscillations in the ionospheric plasma

Abstract. A numerical solution of the dispersion equation for electromagnetic waves in a hot magnetized collisionless plasma has shown that, in a current-free ionospheric plasma, the distortion of the electron distribution function reproducing the downward flow of a thermal electron component and the compensating upward flow of the suprathermal electrons, which are responsible for the resulting heat flux, can destabilize quasi-electrostatic ion sound waves. The numerical analysis, performed with ion densities and electron temperature taken from the data recorded by the Interkosmos-24 (IK-24, Aktivny) satellite, is compared with a VLF spectrum registered at the same time on board. This spectrum shows a wide frequency band emission below the local ion plasma frequency. The direction of the electron heat flux inherent to the assumed model of VLF emission generation is discussed

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Resonant interaction of electron cyclotron waves with a plasma containing arbitrarily drifting suprathermal electrons

Journal of Plasma Physics ◽

10.1017/s0022377800002890 ◽

1985 ◽

Vol 34 (2) ◽

pp. 319-326 ◽

Cited By ~ 7

Author(s):

A. Orefice

Keyword(s):

Electromagnetic Waves ◽

Electron Distribution Function ◽

Resonant Interaction ◽

Electron Cyclotron ◽

Dielectric Tensor ◽

Suprathermal Electrons ◽

Relativistic Treatment ◽

Electron Cyclotron Waves ◽

Plasma Dispersion ◽

The Magnetic Field

A relativistic treatment of the plasma dispersion functions and of the dielectric tensor for electron cyclotron electromagnetic waves is given for non-thermal plasmas where the electron distribution function can be represented as a combination of Maxwellians with arbitrary drifts along the magnetic field.

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On Drift Instabilities in a Collisionless Electron-Proton Plasma from the point of view of Energy Absorption of Resonant Particles

Zeitschrift für Naturforschung A ◽

10.1515/zna-1963-0402 ◽

1963 ◽

Vol 18 (4) ◽

pp. 446-453 ◽

Cited By ~ 3

Author(s):

Asbjørn Kildal

Keyword(s):

Energy Absorption ◽

Constant Electric Field ◽

Wave Length ◽

Collisionless Plasma ◽

Phase Region ◽

Point Of View ◽

Electrostatic Waves ◽

Transverse Current ◽

Special Cases ◽

A Current

The present paper is essentially devoted to the study of instabilities of electrostatic waves in a current-carrying collisionless plasma. As the underlying physical cause of the instabilities is the same as that of the LANDAU damping in an electron plasma, a detailed analysis of the latter is first given. It is shown that the damping may be considered as being due to the fact that there are more electrons in the phase-region where energy is absorbed by the particles from the field than in the phase-region where energy is given up to the field.We then proceed to the evaluation of the energy absorption A of the resonant particles, first in the absence of an external magnet field, B0 , next when the wave is propagated under an arbitrary angle with respect to B0 . When A > 0, the wave is damped, and vice-versa. Without appeal to a dispersion equation, stability criteria can thus be found, dependent on the wave frequency and wave-vector. Next some special cases are investigated and compared with the results of other authors where such results exist.As a consequence of the fact that some ions and electrons, the resonant particles, experience a constant electric field, these particles also experience a constant drift transverse to both E and B0. This drift gives rise to a transverse current which is closely related to the damping or growing of the wave. An expression for this current, averaged over one wave-length is found.

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