Magnetospheric whistler mode ray tracing in a warm background plasma with finite electron and ion temperature

Maxworth, Ashanthi; Gołkowski, Mark

doi:10.1002/2016ja023546

Cited by 18 publications

(18 citation statements)

References 48 publications

(91 reference statements)

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“…Therefore, the secondary electron outflow can alter whistler mode wave propagation and trigger a ducted propagation of quasiparallel waves. This effect could potentially explain the large number of quasiparallel whistler mode waves observed at relatively high latitudes, at ∼20–40° (Agapitov et al, 2013; Santolík et al, 2014), where models of nonducted wave propagation predict a dominance of very oblique waves (Breuillard et al, 2012, 2013; Maxworth & Golkowski, 2017; Yamaguchi et al, 2013).…”

Section: Discussionmentioning

confidence: 99%

Ionosphere Feedback to Electron Scattering by Equatorial Whistler Mode Waves

et al. 2020

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Plasma sheet electron precipitation, much of it driven by whistler mode waves, is critical for magnetosphere-ionosphere coupling. This precipitation leads to a secondary electron population at low altitudes, which moves upward along magnetic field lines to the equatorial plasma sheet. We investigate observational evidence for such electron precipitation and the ionospheric feedback provided by the secondary electron outflows. Using the near-equatorial Time History of Events and Macroscale Interactions during Substorms (THEMIS) mission, we show that whistler mode wave bursts are accompanied by enhanced field-aligned electrons. The properties of these electrons are not related to the whistler mode waves, as would have been expected from local wave-particle interactions. Thus, it is unlikely that the field-aligned electrons are formed by electron Landau resonance with whistler mode waves. This population can be the secondary electron outflows resulting from plasma sheet electron precipitation to the ionosphere. Combining THEMIS, Cluster, and Fast Auroral Snapshot Explorer (FAST) measurements, we show that this field-aligned electron population is also observed at low altitudes, where it is associated with high-frequency electrostatic waves. These low-altitude waves are likely generated by the secondary electron outflows and, in turn, scatter these electrons outside of the loss cone, allowing them to be observed by the wide field-of-view particle instrument on the near-equatorial THEMIS spacecraft. We discuss how this secondary electron population can subsequently alter whistler mode wave generation and propagation in the magnetosphere.

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Section: Discussionmentioning

confidence: 99%

Ionosphere Feedback to Electron Scattering by Equatorial Whistler Mode Waves

et al. 2020

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“…Depending on actual wave properties controlled by the hot plasma dispersion (e.g., Sazhin, ), electron scattering rates due to very oblique waves may increase as compared with quasi‐parallel waves and become very large or else drop down to zero (see discussions in Albert, ; Artemyev et al, ). The critical characteristics determining the total effect of highly oblique chorus waves on resonant electrons are the maximum value N max of the wave refractive index defined by hot plasma effects and/or Landau damping (see Hashimoto et al, ; Horne & Sazhin, ; Kulkarni et al, ; Li et al, ; Maxworth & Golkowski, ; Mourenas et al, ) and the distribution of magnetic wave power near the resonance cone (e.g., Artemyev et al, ; Albert, , and references therein). Both these characteristics can be derived only from a very careful analysis of sufficiently accurate wave, plasma, and electron distribution measurements during very oblique chorus wave observations, allowed for the first time by the Van Allen Probes mission.…”

Section: Introductionmentioning

confidence: 99%

Very Oblique Whistler Mode Propagation in the Radiation Belts: Effects of Hot Plasma and Landau Damping

Artemyev

Mourenas

et al. 2017

Geophysical Research Letters

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Satellite observations of a significant population of very oblique chorus waves in the outer radiation belt have fueled considerable interest in the effects of these waves on energetic electron scattering and acceleration. However, corresponding diffusion rates are extremely sensitive to the refractive index N, controlled by hot plasma effects including Landau damping and wave dispersion modifications by suprathermal (15-100 eV) electrons. A combined investigation of wave and electron distribution characteristics obtained from the Van Allen Probes shows that peculiarities of the measured electron distribution significantly reduce Landau damping, allowing wave propagation with high N ∼ 100-200. Further comparing measured refractive indexes with theoretical estimates incorporating hot plasma corrections to the wave dispersion, we provide the first experimental demonstration that suprathermal electrons indeed control the upper limit of the refractive index of highly oblique whistler mode waves. Such results further support the importance of incorporating very oblique waves into radiation belt models.

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“…The background plasmasphere consists of electron and ions (H + , He + and O + ). This raytracer was later modified at the University of Colorado Denver, to have the option of including finite electron and ion temperature [51]. The background plasma densities used in this work were from the Global Core Plasmasphere Model (GCPM) [55].…”

Section: Raytracing Resultsmentioning

confidence: 99%

Coexistence of Lightning Generated Whistlers, Hiss and Lower Hybrid Noise Observed by e-POP (SWARM-E)–RRI

2020

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Whistler mode waves play a major role in regulating the lifetime of trapped electrons in the Earth’s radiation belts. Specifically, interaction with whistler mode hiss waves is one of the mechanisms that maintains the slot region between the inner and outer radiation belts. The generation mechanism of hiss is a topic still under debate with at least three prominent theories present in the literature. Lightning generated whistlers in their ducted or non-ducted modes are considered to be one of the possible sources of hiss. We present a study of new observations from the Radio Receiver Instrument (RRI) on the Enhanced Polar Outflow Probe (ePOP: also known as SWARM-E). RRI consists of two orthogonal dipole antennas, which enables polarization measurements, when the satellite boresight is parallel to the geomagnetic field. Here we present 105 ePOP - RRI events from 2014–2018, in which lightning whistlers(75) and hiss waves(39) were observed. In more than 50% of those whistler observations, hiss found to co-exist. Moreover, the whistler observations are correlated with observations of wave power at the lower-hybrid resonance. The observations and a whistler mode ray-tracing study suggest that multiple-hop lightning induced whistlers can be a source of hiss and plasma instabilities in the magnetosphere.

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Magnetospheric whistler mode ray tracing in a warm background plasma with finite electron and ion temperature

Cited by 18 publications

References 48 publications

Ionosphere Feedback to Electron Scattering by Equatorial Whistler Mode Waves

Ionosphere Feedback to Electron Scattering by Equatorial Whistler Mode Waves

Very Oblique Whistler Mode Propagation in the Radiation Belts: Effects of Hot Plasma and Landau Damping

Coexistence of Lightning Generated Whistlers, Hiss and Lower Hybrid Noise Observed by e-POP (SWARM-E)–RRI

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