Active Wave Experiments in Space Plasmas: The Z Mode

Benson, Robert F.; Webb, P. A.; Green, J.L.; Carpenter, D. L.; Sonwalkar, V. S.; James, H. G.; Reinisch, B. W.

doi:10.1007/3-540-33203-0_1

Cited by 26 publications

(27 citation statements)

References 58 publications

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“…The discrepancy may be due in part to the sampling periods, temporal variations of the local plasma, or spacecraft charging. In addition, the polarization of the Z-mode emission at this time is left-handed, consistent with Z mode propagating at a frequency less than the plasma frequency [Benson et al, 2006], but above the Z-mode cutoff, f z . In addition, the polarization of the Z-mode emission at this time is left-handed, consistent with Z mode propagating at a frequency less than the plasma frequency [Benson et al, 2006], but above the Z-mode cutoff, f z .…”

Section: Z-mode Observationssupporting

confidence: 59%

Source region and growth analysis of narrowband Z‐mode emission at Saturn

et al. 2016

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Intense Z‐mode emission is observed in the lower density region near the inner edge of the Enceladus torus at Saturn, where these waves may resonate with MeV electrons. The source mechanism of this emission, which is narrow‐banded and most intense near 5 kHz, is not well understood. We survey the Cassini Radio and Plasma Wave Science data to isolate several probable source regions near the inner edge of the Enceladus density torus. Electron phase space distributions are obtained from the Cassini Electron Spectrometer, part of the Cassini Plasma Spectrometer investigation. We perform a plasma wave growth analysis to conclude that an electron temperature anisotropy and possibly a weak loss cone can drive the Z mode as observed. Electrostatic electron acoustic waves and perhaps weak beam modes are also found to be unstable coincident with the Z mode. Quasi‐steady conditions near the Enceladus density torus may result in the observations of narrowband Z‐mode emission at Saturn.

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Section: Z-mode Observationssupporting

confidence: 59%

Source region and growth analysis of narrowband Z‐mode emission at Saturn

et al. 2016

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“…Stix, 1992;Benson et al, 2006). For instance, the curves for N 2 versus ω nearly intersect for wave normal angles <2 • and ω p / ∼ 4.…”

Section: Temporal and Spatial Growth Ratementioning

confidence: 92%

Source mechanism of Saturn narrowband emission

Menietti

Yoon

et al. 2010

Ann. Geophys.

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Abstract. Narrowband emission (NB) is observed at Saturn centered near 5 kHz and 20 kHz and harmonics. This emission appears similar in many ways to Jovian kilometric narrowband emission observed at higher frequencies, and therefore may have a similar source mechanism. Source regions of NB near 20 kHz are believed to be located near density gradients in the inner magnetosphere and the emission appears to be correlated with the occurrence of large neutral plasma clouds observed in the Saturn magnetotail. In this work we present the results of a growth rate analysis of NB emission (∼20 kHz) near or within a probable source region. This is made possible by the sampling of in-situ wave and particle data. The results indicate waves are likely to be generated by the mode-conversion of directly generated Z-mode emission to O-mode near a density gradient. When the local hybrid frequency is close n f ce (n is an integer and f ce is the electron cyclotron frequency) with n=4, 5 or 6 in our case, electromagnetic Z-mode and weak ordinary (O-mode) emission can be directly generated by the cyclotron maser instability.

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“…Many spacecraft have generated Z-mode waves in the ionosphere and magnetosphere using radio sounders, among them the ISIS satellites and the OEDIPUS sounding rockets (e.g., Benson et al 2006). This work has provided a powerful complement to observations of Zmode waves of magnetospheric origin performed on rockets and satellites using plasma wave receivers (e.g., LaBelle and Treumann 2002).…”

Section: Active Z-mode Experiments In Space Plasmasmentioning

confidence: 97%

Advances in Plasmaspheric Wave Research with CLUSTER and IMAGE Observations

et al. 2009

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This paper highlights significant advances in plasmaspheric wave research with CLUSTER and IMAGE observations. This leap forward was made possible thanks to the new observational capabilities of these space missions. On one hand, the multipoint view of the four CLUSTER satellites, a unique capability, has enabled the estimation of wave characteristics impossible to derive from single spacecraft measurements. On the other hand, the IMAGE experiments have enabled to relate large-scale plasmaspheric density structures with 138 A. Masson et al. wave observations and provide radio soundings of the plasmasphere with unprecedented details. After a brief introduction on CLUSTER and IMAGE wave instrumentation, a series of sections, each dedicated to a specific type of plasmaspheric wave, put into context the recent advances obtained by these two revolutionary missions.

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Active Wave Experiments in Space Plasmas: The Z Mode

Cited by 26 publications

References 58 publications

Source region and growth analysis of narrowband Z‐mode emission at Saturn

Source region and growth analysis of narrowband Z‐mode emission at Saturn

Source mechanism of Saturn narrowband emission

Advances in Plasmaspheric Wave Research with CLUSTER and IMAGE Observations

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