A survey of equatorial magnetospheric wave activity between 5 and 8 RE

Koons, H. C.; Roeder, J. L.

doi:10.1016/0032-0633(90)90136-e

Cited by 130 publications

(156 citation statements)

References 13 publications

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“…Electromagnetic chorus have been studied extensively in the Earth's magnetosphere (see Smith, 1974, 1977;Anderson and Maeda, 1977;Koons and Roeder, 1990;Meredith et al, 2001Meredith et al, , 2003, for chorus observational statistics). These waves are believed to be responsible for the creation of relativistic electrons in the radiation belts (Horne and Thorne, 1998) and may define the structure of the belts themselves (Horne et al, 2005).…”

Section: Observationsmentioning

confidence: 99%

Polarization properties of Gendrin mode waves observed in the Earth's magnetosphere: observations and theory

Verkhoglyadova

Tsurutani

2009

Ann. Geophys.

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Abstract. We show a case of an outer zone magnetospheric electromagnetic wave propagating at the Gendrin angle, within uncertainty of the measurements. The chorus event occurred in a "minimum B pocket". For the illustrated example, the measured angle of wave propagation relative to the ambient magnetic field θ kB was 58 • ± 4 • . For this event the theoretical Gendrin angle was 62 • . Cold plasma model is used to demonstrate that Gendrin mode waves are right-hand circularly polarized, in excellent agreement with the observations.

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Section: Observationsmentioning

confidence: 99%

Polarization properties of Gendrin mode waves observed in the Earth's magnetosphere: observations and theory

Verkhoglyadova

Tsurutani

2009

Ann. Geophys.

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“…Spurious data points, data spikes and periods of instrumental downtime were flagged and ignored in the analysis. Whistler mode chorus is commonly observed in the range 0.1f ce < f < 0.8f ce (Koons and Roeder, 1990). Therefore, we initially determined the wave spectral intensity as a function of relative frequency, x = f/f ce , in the range 0.02 < x < 1 at an 8.192 s time resolution corresponding to the fastest sweep of the Sweep Frequency Receiver.…”

Section: Whistler Mode Chorusmentioning

confidence: 99%

Evidence for acceleration of outer zone electrons to relativistic energies by whistler mode chorus

et al. 2002

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Abstract. We use plasma wave and electron data from the Combined Release and Radiation Effects Satellite (CRRES) to investigate the viability of a local stochastic electron acceleration mechanism to relativistic energies driven by gyroresonant interactions with whistler mode chorus. In particular, we examine the temporal evolution of the spectral response of the electrons and the waves during the 9 October 1990 geomagnetic storm. The observed hardening of the electron energy spectra over about 3 days in the recovery phase is coincident with prolonged substorm activity, as monitored by the A E index and enhanced levels of whistler mode chorus waves. The observed spectral hardening is observed to take place over a range of energies appropriate to the resonant energies associated with Doppler-shifted cyclotron resonance, as supported by the construction of realistic resonance curves and resonant diffusion surfaces. Furthermore, we show that the observed spectral hardening is not consistent with energy-independent radial diffusion models. These results provide strong circumstantial evidence for a local stochastic acceleration mechanism, involving the energisation of a seed population of electrons with energies of the order of a few hundred keV to relativistic energies, driven by wave-particle interactions involving whistler mode chorus. The results suggest that this mechanism contributes to the reformation of the relativistic outer zone population during geomagnetic storms, and is most effective when the recovery phase is characterised by prolonged substorm activity. An additional significant result of this paper is that we demonstrate that the lower energy part of the storm-time electron distribution is in steady-state balance, in accordance with the Kennel and Petschek (1966) theory of limited stably-trapped particle fluxes.

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“…Whistler mode waves are intense electromagnetic emissions that occur ubiquitously in the Earth's inner magnetosphere, typically in two distinct frequency bands: a lower band (0.1-0.5 f ce , where f ce is the electron gyrofrequency) and an upper band (0.5-0.8 f ce ) with a gap in wave power at 0.5 f ce [Burtis and Helliwell, 1969;Smith, 1974, 1977;Koons and Roeder, 1990;Meredith et al, 2001;Li et al, 2012]. The whistler mode wave emissions are generally believed to be excited in the vicinity of the geomagnetic equatorial plane [LeDocq et al, 1998;Lauben et al, 2002;Santolik et al, 2005;Li et al, 2009], but another source region may also be present at high latitudes in the dayside magnetosphere [Tsurutani and Smith, 1977;Tsurutani et al, 2009].…”

Section: Introductionmentioning

confidence: 99%

New evidence for generation mechanisms of discrete and hiss‐like whistler mode waves

Gao

Thorne

et al. 2014

Geophysical Research Letters

103

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Linear theory suggests that whistler mode wave growth rates are proportional to the ratio of hot electron (~1 to 30 keV) density to total electron density (N h /N t ), whereas nonlinear wave theory suggests that an optimum linear growth rate is required to generate rising tone chorus from hiss-like emissions. Using the Time History of Events and Macroscale Interactions during Substorms waveform data collected by three probes over the past~5 years, we investigate the correlation between N h /N t and wave amplitude/wave occurrence rate for rising tone, falling tone, and hiss-like emissions separately. Statistical results show that the rising and falling tones preferentially occur in the region with a limited N h /N t range, whereas both the occurrence rate and wave amplitudes of hiss-like emissions become larger for higher values of N h /N t . Our statistical results not only provide an important clue on the generation mechanism of hiss-like emissions, but also provide supporting experimental evidence for the nonlinear theory of generating rising tone chorus.

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A survey of equatorial magnetospheric wave activity between 5 and 8 RE

Cited by 130 publications

References 13 publications

Polarization properties of Gendrin mode waves observed in the Earth's magnetosphere: observations and theory

Polarization properties of Gendrin mode waves observed in the Earth's magnetosphere: observations and theory

Evidence for acceleration of outer zone electrons to relativistic energies by whistler mode chorus

New evidence for generation mechanisms of discrete and hiss‐like whistler mode waves

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