A new mechanism of whistler wave generation by amplitude modulated HF waves in the polar electrojet

Kuo, Spencer; Koretzky, E.; Lee, M. C.

doi:10.1029/1999gl900356

Cited by 10 publications

(11 citation statements)

References 23 publications

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“…[1][2][3][4][5][6] These ionospheric irregularities with a broad range of scale lengths have been observed in natural events and in high frequency ͑HF͒ heating experiments. [1][2][3][4][5][6] These ionospheric irregularities with a broad range of scale lengths have been observed in natural events and in high frequency ͑HF͒ heating experiments.…”

Section: Introductionmentioning

confidence: 88%

Beat excitation of whistlers in the presence of field aligned irregularities in the ionosphere

2008

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In equatorial ionospheric plasma, embedded with a density ripple, a low frequency whistler can be resonantly excited by the nonlinear mixing of two high frequency radio waves launched from the ground at an oblique angle. A suitable configuration is where the earth magnetic field is along ẑ (horizontal), ripple wave number q⃗‖ŷ (horizontal), and high frequency wave numbers are k⃗1=k1cosθẑ+k1sinθ(cosϕx̂+sinϕŷ), k⃗2=−k2cosθẑ+k2sinθ(cosϕx̂−sinϕŷ). Phase matching conditions are satisfied for large θ and small ϕ. The radio waves exert a ponderomotive force on electrons at the beat frequency imparting them an oscillatory velocity with a component perpendicular to the magnetic field. This velocity, in conjunction with the density ripple, produces a current that drives the whistler. The Ohmic nonlinearity is found to be relatively weaker in comparison to ponderomotive nonlinearity at higher heights. However in the E-region, this nonlinearity reinforces with the ponderomotive nonlinearity and can improve the whistler power generation.

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Section: Introductionmentioning

confidence: 88%

Beat excitation of whistlers in the presence of field aligned irregularities in the ionosphere

2008

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“…Therefore, according to the coupling mechanism proposed by Kuo et al (1999) between k i and x i components of both wave fields of the ion-acoustic and quasitransverse whistler modes, a substantial part of each current sheet is modulated in a common ELF range. Assuming the ionopause conditions of our model be valuable for the time of Huygens descent, which lead to a modulation frequency ranging between 25 and 45 Hz (Béghin, 2014), the involved current sheets should actually act as current antennas feeding the SR cavity at around 36 Hz.…”

Section: Interface Region Between Titan's Upper Atmosphere and Saturnmentioning

confidence: 99%

Self-consistent modeling of induced magnetic field in Titan’s atmosphere accounting for the generation of Schumann resonance

Béghin

2015

Icarus

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“…Nevertheless, an explanation of the modulation mechanism of current sheets in the Earth's polar electrojet, forced by HF heating, has been proposed by Kuo et al . [] to be the source of stimulated whistler waves propagating downward. In the case of Titan, the natural conductivity is shown in section 3 to be able to overpass by itself the threshold of current‐driven instability (Figure ).…”

Section: Coupling Mechanism Between Ion‐acoustic Turbulence and Whistmentioning

confidence: 99%

The atypical generation mechanism of Titan's Schumann resonance

Béghin

2014

JGR Planets

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The observation of a presumed Schumann resonance (SR) during the landing of the Huygens Probe in Titan's atmosphere on January 2005 was subsequently reported and interpreted by Béghin et al. (2007Béghin et al. ( , 2009Béghin et al. ( , 2010Béghin et al. ( , 2012 as being generated through the interaction of Saturn's magnetosphere with Titan's ionosphere rather than from the lightning activity that prevails on Earth. Beyond this atypical behavior, the existence of a single mode instead of the usual multimodal structure of terrestrial SRs and a comprehensive analysis of the physical generation mechanism remained to be investigated. The purpose of the present work is to draw up the baselines of a global model reconciling the Huygens data and the proposed generation mechanism. Based upon relevant observations obtained after several tenths of Titan's flybys by the Cassini orbiter, the modeling involves macro plasma physics processes as well as a global analysis of the mechanisms at the moon's scale. The clue to the SR's generation mechanism is shown to be the low-frequency modulation of the Pedersen current sheets that are induced in the ionopause region by the corotating Saturn's magnetosphere. The modulation principle involves a wave coupling between the ion-acoustic instabilities driven by the longitudinal current sheets and the electromagnetic quasi-transverse whistler mode. The spectral distribution of the sole second eigenmode seen by the Huygens Probe is found to comply with the ionopause plasma parameters measured by Cassini during the bipolar configuration of Titan-Saturn interaction that is thought to have occurred during the probe descent in the atmosphere.

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A new mechanism of whistler wave generation by amplitude modulated HF waves in the polar electrojet

Cited by 10 publications

References 23 publications

Beat excitation of whistlers in the presence of field aligned irregularities in the ionosphere

Beat excitation of whistlers in the presence of field aligned irregularities in the ionosphere

Self-consistent modeling of induced magnetic field in Titan’s atmosphere accounting for the generation of Schumann resonance

The atypical generation mechanism of Titan's Schumann resonance

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