Microwave interactions with a magnetized plasma near the electron cyclotron frequency

AbstractThe self-focusing of an intense right circularly polarized Gaussian laser pulse in magnetized plasma is studied. The ions are taken to be immobile and relativistic mass effect is incorporated in both the plasma frequency (ωp) and the electron cyclotron frequency (ωc) while determining the ponderomotive force on electrons. The ponderomotive force causes electron expulsion when the effective electron cyclotron frequency is below twice the laser frequency. The nonlinear plasma dielectric function due to ponderomotive and relativistic effects is derived, which is then employed in beam-width parameter equation to study the self-focusing of the laser beam. From this, we estimate the importance of relativistic self-focusing in comparison with ponderomotive self-focusing at moderate laser intensities. The beam width parameter decreases with magnetic field indicating better self-focusing. When the laser intensity is very high, the relativistic gamma factor can be modeled as ${\rm \gamma} = 0.8\left({{{{\rm \omega} _c } / {\rm \omega} }} \right)+ \sqrt {1 + a_0^2 }$γ=0.8(ωc/ω)+1+a02 where ω and a0 are the laser frequency and the normalized laser field strength, respectively. The cyclotron effects on the self-focusing of laser pulse are reduced at high field strengths.

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Radial variation of whistler-mode chorus: first results from the STAFF/DWP instrument on board the Double Star TC-1 spacecraft

Annales Geophysicae ◽

10.5194/angeo-23-2937-2005 ◽

2005 ◽

Vol 23 (8) ◽

pp. 2937-2942 ◽

Cited By ~ 45

Author(s):

O. Santolík ◽

E. Macúšová ◽

K. H. Yearby ◽

N. Cornilleau-Wehrlin ◽

H. StC. K. Alleyne

Keyword(s):

Cyclotron Frequency ◽

Power Spectra ◽

Double Star ◽

Electron Cyclotron ◽

Radial Variation ◽

Whistler Mode ◽

Electron Cyclotron Frequency ◽

The Earth ◽

First Results ◽

Initial Results

Abstract. We use the first measurements of the STAFF/DWP instrument on the Double Star TC-1 spacecraft to investigate whistler-mode chorus. We present initial results of a systematic study on radial variation of dawn chorus. The chorus events show an increased intensity at L parameter above 6. This is important for the possible explanation of intensifications of chorus, which were previously observed closer to the Earth at higher latitudes. Our results also indicate that the upper band of chorus at frequencies above one-half of the electron cyclotron frequency disappears for L above 8. The lower band of chorus is observed at frequencies below 0.4 of the electron cyclotron frequency up to L of 11-12. The maxima of the chorus power spectra are found at slightly lower frequencies compared to previous studies. We do not observe any distinct evolution of the position of the chorus frequency band as a function of L. More data of the TC-1 spacecraft are needed to verify these initial results and to increase the MLT coverage.

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Conversion of normal waves in the electron-cyclotron frequency range at the critical surface in a cold anisotropic plasma inhomogeneous in two dimensions

Plasma Physics Reports ◽

10.1134/s1063780x07020043 ◽

2007 ◽

Vol 33 (2) ◽

pp. 109-116 ◽

Cited By ~ 21

Author(s):

A. Yu. Popov ◽

A. D. Piliya

Keyword(s):

Cyclotron Frequency ◽

Two Dimensions ◽

Electron Cyclotron ◽

Anisotropic Plasma ◽

Critical Surface ◽

Frequency Range ◽

Normal Waves ◽

Electron Cyclotron Frequency

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The absorption mechanism of the ordinary mode propagating perpendicularly to the magnetic field at the electron cyclotron frequency

The Physics of Fluids ◽

10.1063/1.863952 ◽

1982 ◽

Vol 25 (9) ◽

pp. 1605 ◽

Cited By ~ 28

Author(s):

R. A. Cairns

Keyword(s):

Magnetic Field ◽

Cyclotron Frequency ◽

Electron Cyclotron ◽

Absorption Mechanism ◽

Ordinary Mode ◽

Electron Cyclotron Frequency ◽

The Magnetic Field

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Electromagnetic cyclotron-loss-cone instability associated with weakly relativistic electrons

Journal of Plasma Physics ◽

10.1017/s0022377800000453 ◽

1982 ◽

Vol 28 (3) ◽

pp. 503-525 ◽

Cited By ~ 65

Author(s):

H. K. Wong ◽

C. S. Wu ◽

F. J. Ke ◽

R. S. Schneider ◽

L. F. Ziebell

Keyword(s):

Cyclotron Frequency ◽

Maximum Growth ◽

Basic Mechanism ◽

Electron Cyclotron ◽

Relativistic Electrons ◽

Electron Component ◽

Loss Cone ◽

Electron Cyclotron Frequency ◽

Cone Type ◽

Consistent Manner

The amplification of fast extraordinary mode waves with frequencies very close to the electron cyclotron frequency is investigated for a plasma which consists of a weakly relativistic electron component with a loss-cone type distribution and a cold background electron component. The basic mechanism of the amplification is attributed to a relativistic cyclotron resonance between the wave and the energetic electrons. The method employed in the present analysis enables us to solve the dispersion relation in a self-consistent manner for arbitrary ratio of the densities of the energetic and background electrons. It is found that the maximum growth rates occur at certain values of ω2pe/Ω2e and the angular dependence of the growth rate is sensitive to the ratios ω2pe/Ω2e and ne/nb. Here ωpe and Ωe are the electron plasma frequency and the electron cyclotron frequency, respectively, and ne and nb denote the number densities of the energetic and background electrons, respectively.

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