Le guidage des whistlers par le champ magnetique

Gendrin, R.

doi:10.1016/0032-0633(61)90096-4

Cited by 117 publications

(98 citation statements)

References 5 publications

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“…This result indicates that the waves may be amplified by the electron gyroresonance instability, as suggested by Kennel and Petschek [1966] and by Thorne et al [1973,1979]. Some of their energy, however, is found at wave-normal directions highly inclined to the Earth's magnetic field, near the Gendrin angle; recall that at this angle the energy again propagates along the Earth's magnetic field [Gendrin, 1960] generated by a different mechanism, but for our cases we cannot rule out the possibility that all of the waves originated with their normals close to B0, and subsequently a small part of the energy escaped to the Gendrin angle either by propagation or by scattering from plasma density irregularities. In the cases for May 2, 1997, and November 24, 1996, discussed above, the region of wave amplification may be located near the equator, at the magnetic latitudes q-1.8 ø and +8.5 ø respectively.…”

Section: Discussionmentioning

confidence: 60%

Propagation analysis of plasmaspheric hiss using Polar PWI measurements

Santolı́k¹,

Parrot²,

Storey³

et al. 2001

Geophysical Research Letters

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Abstract. We have analyzed high-rate waveform data, taken Storey et al. [1991] however observed hiss emissions even by the POLAR Plasma Wave Instrument at high altitudes in when, after long periods of magnetic calm, the plasmapause the equatorial plasmasphere, to study plasmaspheric hiss in the was absent. They also found that the waves often propagate at range of frequencies between 100 Hz and several kHz. These large angles from B0, even in the equatorial region. This means emissions are found almost everywhere in the plasmasphere, these waves cannot be generated exactly in the way Kennel and their origin is still controversial. Our analysis of several and Petschek [1966] suggested. These results do not directly cases shows that most of the waves were propagating more or contradict the theory of Thorne et al. [ 1973, 1979], but they do less parallel to the Earth's magnetic field, but sometimes a few suggest that under certain circumstances some other mechanism of them were propagating obliquely with their normals near may be acting. Indeed, highly oblique wave propagation fits a the Gendrin angle. Evidence of amplification was found near theory developed by Draganov et al.

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Section: Discussionmentioning

confidence: 60%

Propagation analysis of plasmaspheric hiss using Polar PWI measurements

Santolı́k¹,

Parrot²,

Storey³

et al. 2001

Geophysical Research Letters

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“…Because of its general relevance for plasma wave emission, which has been pointed out in earlier studies by Gendrin (1961), Sauer et al (2002) and Sydora et al (2007), the point of maximum phase velocity is marked in this context by "GSS" to indicate the generalization of Gendrin's concept originally developed for usual whistlers in overdense plasmas (G < 1). Using the basic dispersion relation D(ω,k) = 0 according to Eq.…”

Section: Dispersion Relationmentioning

confidence: 91%

Whistler-Langmuir oscillitons and their relation to auroral hiss

Sauer

Sydora

2011

Ann. Geophys.

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Abstract.A new type of oscilliton (soliton with superimposed spatial oscillations) is described which arises in plasmas if the electron cyclotron frequency e is larger than the electron plasma frequency ω e , which is a typical situation for auroral regions in planetary magnetospheres. Both highfrequency modes of concern, the Langmuir and the whistler wave, are completely decoupled if they propagate parallel to the magnetic field. However, for oblique propagation two mixed modes are created with longitudinal and transverse electric field components. The lower mode (in the literature commonly called the whistler mode, e.g. Gurnett et al., 1983) has whistler wave characteristics at small wave numbers and asymptotically transforms into the Langmuir mode. As a consequence of the coupling between these two modes, with different phase velocity dependence, a maximum in phase velocity appears at finite wave number. The occurrence of such a particular point where phase and group velocity coincide creates the condition for the existence of a new type of oscillating nonlinear stationary structure, which we call the whistler-Langmuir (WL) oscilliton. After determining, by means of stationary dispersion theory, the parameter regime in which WL oscillitons exist, their spatial profiles are calculated within the framework of cold (non-relativistic) fluid theory. Particle-in-cell (PIC) simulations are used to demonstrate the formation of WL oscillitons which seem to play an important role in understanding electron beam-excited plasma radiation that is observed as auroral hiss in planetary magnetospheres far away from the source region.

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“…As already mentioned in Sect. 2.1, the corresponding waves are also called Gendrin modes (Gendrin, 1961). Their physical relevance has recently been discussed in a paper by Verkhoglyadova and Tsurutani (2009).…”

Section: Whistler Oscillitons (Nonlinear Gendrin Modes)mentioning

confidence: 98%

“…Our numerical studies of beam-excited whistlers are completed by the addition of some useful analytical expressions that are related to the specific whistler wave mode with kc/ω e = 1, which has been called the Gendrin mode (Gendrin, 1961;Verkhoglyadova and Tsurutani, 2009). If we start from the whistler dispersion relation, assuming ω e e , the real frequency is expressed as…”

Section: Fluid Approachmentioning

confidence: 99%

Beam-excited whistler waves at oblique propagation with relation to STEREO radiation belt observations

Sauer

Sydora

2010

Ann. Geophys.

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Abstract. Isotropic electron beams are considered to explain the excitation of whistler waves which have been observed by the STEREO satellite in the Earth's radiation belt. Aside from their large amplitudes (∼240 mV/m), another main signature is the strongly inclined propagation direction relative to the ambient magnetic field. Electron temperature anisotropy with T e⊥ > T e , which preferentially generates parallel propagating whistler waves, can be excluded as a free energy source. The instability arises due to the interaction of the Doppler-shifted cyclotron mode ω = − e + kV b cosθ with the whistler mode in the wave number range of kc/ω e ≤ 1 (θ is the propagation angle with respect to the background magnetic field direction, ω e is the electron plasma frequency and e the electron cyclotron frequency). Fluid and kinetic dispersion analysis have been used to calculate the growth rate of the beam-excited whistlers including the most important parameter dependencies. One is the beam velocity (V b ) which, for instability, has to be larger than about 2V Ae , where V Ae is the electron Alfvén speed. With increasing V Ae the propagation angle (θ) of the fastest growing whistler waves shifts from θ ∼ 20 • for V b = 2V Ae to θ ∼ 80 • for V b = 5V Ae . The growth rate is reduced by finite electron temperatures and disappears if the electron plasma beta (β e ) exceeds β e ∼ 0.2. In addition, Gendrin modes (kc/ω e ≈ 1) are analyzed to determine the conditions under which stationary nonlinear waves (whistler oscillitons) can exist. The corresponding spatial wave profiles are calculated using the full nonlinear fluid approach. The results are compared with the STEREO satellite observations.

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Le guidage des whistlers par le champ magnetique

Cited by 117 publications

References 5 publications

Propagation analysis of plasmaspheric hiss using Polar PWI measurements

Propagation analysis of plasmaspheric hiss using Polar PWI measurements

Whistler-Langmuir oscillitons and their relation to auroral hiss

Beam-excited whistler waves at oblique propagation with relation to STEREO radiation belt observations

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