Dynamics of ion sound waves in the front of the terrestrial bow shock

Giagkiozis, Ioannis; Walker, S. N.; Balikhin, M. A.

doi:10.5194/angeo-29-805-2011

Cited by 6 publications

(9 citation statements)

References 28 publications

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“…Higher-order spectra have been used in various previous experiments for studying the mode coupling in laboratory plasma [Kim andPowers, 1979], rocket data [e.g., LaBelle andLund, 1992;Larsen et al, 2002;Dyrud et al, 2006;Giagkiozis et al, 2011], or satellite experiments [e.g., Lagoutte et al, 1989;Masson et al, 1999]. Here we first presented the results from the Fourier bicoherence and extended the analysis to wavelet-based bicoherence, which is more robust and less biased when studying short data segments [van Milligen et al, 1995;Dudok de Wit and Krasnosel'skikh, 1995].…”

Section: Discussionmentioning

confidence: 99%

“…Additionally, it produces significantly less bias than the Fourier bicoherence [ Dudok de Wit and Krasnosel'skikh , ]. Consequently the wavelet approach has been widely applied in capturing the formation of transient coupling in turbulence plasma media for space and laboratory [e.g., van Milligen et al , ; Dudok de Wit and Krasnosel'skikh , ; Savin et al , ; Dyrud et al , ; Giagkiozis et al , ; Graham et al , ]. Here we apply the wavelet bicoherence analysis to Case A and Case B.…”

Section: Higher‐order Power Spectramentioning

confidence: 99%

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Plasma turbulence and coherent structures in the polar cap observed by the ICI‐2 sounding rocket

et al. 2015

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The electron density data from the ICI‐2 sounding rocket experiment in the high‐latitude F region ionosphere are analyzed using the higher‐order spectra and higher‐order statistics. Two regions of enhanced fluctuations are chosen for detailed analysis: the trailing edge of a polar cap patch and an electron density enhancement associated with particle precipitation. While these two regions exhibit similar power spectra, our analysis reveals that their internal structures are significantly different. The structures on the edge of the polar cap patch are likely due to nonlinear wave interactions since this region is characterized by intermittency and significant coherent mode coupling. The plasma enhancement subjected to precipitation, however, exhibits stronger random characteristics with uncorrelated phases of density fluctuations. These results suggest that particle precipitation plays a fundamental role in ionospheric plasma structuring creating turbulent‐like structures. We discuss the physical mechanisms that cause plasma structuring as well as the possible processes for the low‐frequency part of the spectrum in terms of plasma instabilities.

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Section: Discussionmentioning

confidence: 99%

Section: Higher‐order Power Spectramentioning

confidence: 99%

Plasma turbulence and coherent structures in the polar cap observed by the ICI‐2 sounding rocket

et al. 2015

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“…When harmonics are not apparent and polarization is not predominantly along the magnetic field, it can be difficult to distinguish between cyclotron harmonic waves and Dopplershifted ion acoustic waves, though power spectra above f ce tend to be broader for the cyclotron harmonic waves than for traditional ion acoustic waves [e.g., Wilson et al, 2010, Figure 10] and they typically exhibit the comma-shaped polarization discussed previously. More sophisticated analysis techniques [e.g., Giagkiozis et al, 2011] may be needed to identify the difference between these two types of waves when clear harmonics are not present.…”

Section: Identification Of Cyclotron Harmonic Wavesmentioning

confidence: 99%

“…data, modify the shock potential structure and can provide significant energy dissipation at the shock transition region. Waveform data from Polar [Hull et al, 2006] and Cluster [Giagkiozis et al, 2011] have also been used to identify large amplitude ( 80 mV/m) ion acoustic waves at the bow shock transition region. An important observation from these and other waveform analyses [Wilson et al, 2007[Wilson et al, , 2010 is that these waves can be large amplitude and bursty.…”

Section: Introductionmentioning

confidence: 99%

STEREO and Wind observations of intense cyclotron harmonic waves at the Earth's bow shock and inside the magnetosheath

et al. 2013

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[1] We present the first observations of electron cyclotron harmonic waves at the Earth's bow shock from STEREO and Wind burst waveform captures. These waves are observed at magnetic field gradients at a variety of shock geometries ranging from quasi-parallel to nearly perpendicular along with whistler mode waves, ion acoustic waves, and electrostatic solitary waves. Large amplitude cyclotron harmonic waveforms are also observed in the magnetosheath in association with magnetic field gradients convected past the bow shock. Amplitudes of the cyclotron harmonic waves range from a few tens to more than 500 mV/m peak-peak. A comparison between the short (15 m) and long (100 m) Wind spin plane antennas shows a similar response at low harmonics and a stronger response on the short antenna at higher harmonics. This indicates that wavelengths are not significantly larger than 100 m, consistent with the electron cyclotron radius. Waveforms are broadband and polarizations are distinctively comma-shaped with significant power both perpendicular and parallel to the magnetic field. Harmonics tend to be more prominent in the perpendicular directions. These observations indicate that the waves consist of a combination of perpendicular Bernstein waves and field-aligned waves without harmonics. A likely source is the electron cyclotron drift instability which is a coupling between Bernstein and ion acoustic waves. These waves are the most common type of high-frequency wave seen by STEREO during bow shock crossings and magnetosheath traversals and our observations suggest that they are an important component of the high-frequency turbulent spectrum in these regions.

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“…The transfer function (6) was then solved using an iterative scheme, beginning by estimating the value of the linear transfer function, using it to calculate the quadratic transfer function, followed by reestimating the linear transfer function coefficient and so on until the changes in the linear/quadratic transfer function coefficients is less than a predefined threshold level. The solution methodology used in this study has previously been used in studies of shock turbulence (Giagkiozis et al, 2011). A similar least squares fit solution was also used by Dudok de Wit et al (1999) and McCaffrey et al (2000) for studies of turbulence at the terrestrial bow shock.…”

Section: Transfer Functionmentioning

confidence: 99%

Equatorial Magnetosonic Waves: Do Nonlinear Interactions Play a Role in Their Evolution?

et al. 2020

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The occurrence of nonlinear interactions between discrete wave frequencies has been shown to play a significant role in the propagation and evolution of some plasma wave modes. In this paper we take advantage of closely spaced Cluster measurements to investigate the possibility nonlinear interactions occurring between the discrete emissions that are observed in a region of Equatorial Magnetosonic Wave generation. Based on transfer function analysis, it is shown that the role of nonlinear interactions plays a negligible role in the wave evolution as the emissions propagate from one satellite to the other. A bicoherence analysis of the individual signals also fails to find the existence of nonlinear interactions in the evolution of equatorial magnetosonic waves. Plain Language SummaryIn space plasmas, oscillations in the background electric and magnetic fields grow from energy sources associated with populations of plasma particles that are not in equilibrium. Once generated, these plasma waves may interact with the background plasma passing their energy back to the particles. In addition, waves at different frequencies may interact with each other, passing some of their energy to waves at a third frequency. There interactions may affect the evolution of these waves as they propagate in space. In this study, we examine a specific type of plasma wave, namely, equatorial magnetosonic waves, that exist as a set of harmonic frequencies related to the gyration of a proton in a magnetic field, looking for evidence of so called wave-wave interactions in a region. No evidence is found for such interactions. Thus, it appears that these waves will evolve by exchanging energy with plasma particles but not plasma waves.

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Dynamics of ion sound waves in the front of the terrestrial bow shock

Cited by 6 publications

References 28 publications

Plasma turbulence and coherent structures in the polar cap observed by the ICI‐2 sounding rocket

Plasma turbulence and coherent structures in the polar cap observed by the ICI‐2 sounding rocket

STEREO and Wind observations of intense cyclotron harmonic waves at the Earth's bow shock and inside the magnetosheath

Equatorial Magnetosonic Waves: Do Nonlinear Interactions Play a Role in Their Evolution?

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