Dependence of quasi‐linear diffusion coefficients on wave parameters

Albert, J. M.

doi:10.1029/2012ja017718

Cited by 26 publications

(47 citation statements)

References 51 publications

(79 reference statements)

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“…Then, the functionĜ has finite values up to at least θ = 80 • and varies weakly with θ (see n = −1 harmonic for 100 keV particles and n = −10 harmonic for 1 MeV particles). In particular,Ĝ attains now finite values in the θ domain comprised between the Gendrin and resonance cone angles, falling sharply when θ gets close to θ r (ω) as explained by Mourenas et al (2012b) and Albert (2012). As a result, all particles with α 0 > 20 • may be scattered with approximately the same rate (one can find a peak of D B at intermediate values of α 0 in Fig.…”

Section: Electron Diffusion Coefficients For Interaction With Lower-bmentioning

confidence: 78%

Parametric validations of analytical lifetime estimates for radiation belt electron diffusion by whistler waves

et al. 2013

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The lifetimes of electrons trapped in Earth's radiation belts can be calculated from quasi-linear pitch-angle diffusion by whistler-mode waves, provided that their frequency spectrum is broad enough and/or their average amplitude is not too large. Extensive comparisons between improved analytical lifetime estimates and full numerical calculations have been performed in a broad parameter range representative of a large part of the magnetosphere from L ~ 2 to 6. The effects of observed very oblique whistler waves are taken into account in both numerical and analytical calculations. Analytical lifetimes (and pitch-angle diffusion coefficients) are found to be in good agreement with full numerical calculations based on CRRES and Cluster hiss and lightning-generated wave measurements inside the plasmasphere and Cluster lower-band chorus waves measurements in the outer belt for electron energies ranging from 100 keV to 5 MeV. Comparisons with lifetimes recently obtained from electron flux measurements on SAMPEX, SCATHA, SAC-C and DEMETER also show reasonable agreement

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Section: Electron Diffusion Coefficients For Interaction With Lower-bmentioning

confidence: 78%

Parametric validations of analytical lifetime estimates for radiation belt electron diffusion by whistler waves

et al. 2013

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“…resonance near Bessel function maximum) is not available anymore for N N limit . If very oblique waves with such very large N were present, then their weight in diffusion rates would be dominant and scattering could decrease down to zero as predicted by Albert (2012) in the limit of extremely large N .…”

Section: Number Of Contributing Resonances For Quasi-parallel and Vermentioning

confidence: 91%

“…Although most models of diffusion coefficients used to rely on the assumption of quasiparallel chorus waves such that θ < θ g (e.g., see Lyons et al 1972;Summers 2005;Glauert and Horne 2005;Shprits et al 2007), several recent works have started to take into account very oblique chorus waves Albert 2012;) and hiss waves Glauert et al 2014).…”

Section: Taking Wave Obliquity Into Accountmentioning

confidence: 99%

Oblique Whistler-Mode Waves in the Earth’s Inner Magnetosphere: Energy Distribution, Origins, and Role in Radiation Belt Dynamics

et al. 2016

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International audienceIn this paper we review recent spacecraft observations of oblique whistler-mode waves in the Earth’s inner magnetosphere as well as the various consequences of the presence of such waves for electron scattering and acceleration. In particular, we survey the statistics of occurrences and intensity of oblique chorus waves in the region of the outer radiation belt, comprised between the plasmapause and geostationary orbit, and discuss how their actual distribution may be explained by a combination of linear and non-linear generation, propagation, and damping processes. We further examine how such oblique wave populations can be included into both quasi-linear diffusion models and fully nonlinear models of wave-particle interaction. On this basis, we demonstrate that varying amounts of oblique waves can significantly change the rates of particle scattering, acceleration, and precipitation into the atmosphere during quiet times as well as in the course of a storm. Finally, we discuss possible generation mechanisms for such oblique waves in the radiation belts. We demonstrate that oblique whistler-mode chorus waves can be considered as an important ingredient of the radiation belt system and can play a key role in many aspects of wave-particle resonant interactions

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“…The competition between these two processes results in the observed variation of the g ( θ ) distribution with latitude, MLT, L shell, and geomagnetic activity. Although parallel (or quasi‐parallel) wave propagation θ ≈ 0 is often considered in many modern models of quasi‐linear diffusion by whistler mode waves [ Glauert and Horne , ; Shprits et al , ; Summers et al , ; Albert , ], it has also been shown that a finite (>45°) value of the mean θ angle could play a potentially important role for electron resonant scattering [ Shprits and Ni , ; Artemyev et al , ; Albert , ; Ni et al , ; Glauert et al , ; Li et al , ]. Recent spacecraft observations have revealed the existence of a subpopulation of whistler mode waves with very oblique θ ∈[ θ g , θ r ] [ Li et al , ; Agapitov et al , ], where θ g and θ r are the Gendrin and resonance cone angles [ Gendrin , ].…”

Section: Introductionmentioning

confidence: 99%

Empirical model of lower band chorus wave distribution in the outer radiation belt

et al. 2015

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Accurate modeling of wave‐particle interactions in the radiation belts requires detailed information on wave amplitudes and wave‐normal angular distributions over L shells, magnetic latitudes, magnetic local times, and for various geomagnetic activity conditions. In this work, we develop a new and comprehensive parametric model of VLF chorus waves amplitudes and obliqueness in the outer radiation belt using statistics of VLF measurements performed in the chorus frequency range during 10 years (2001–2010) aboard the Cluster spacecraft. We used data from the Spatio‐Temporal Analysis of Field Fluctuations‐Spectrum Analyzer experiment, which spans a total frequency range from 8 Hz to 4 kHz. The statistical model is presented in the form of an analytical function of latitude and Kp (or Dst) index for day and night sectors of the magnetosphere and for two ranges of L shells above the plasmapause, from L = 4 to 5 and from L = 5 to 7. This model can be directly applied for numerical calculations of charged particle pitch angle and energy diffusion coefficients in the outer radiation belt, allowing to study with unprecedented detail their statistical properties as well as their important spatiotemporal variations with geomagnetic activity.

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Dependence of quasi‐linear diffusion coefficients on wave parameters

Cited by 26 publications

References 51 publications

Parametric validations of analytical lifetime estimates for radiation belt electron diffusion by whistler waves

Parametric validations of analytical lifetime estimates for radiation belt electron diffusion by whistler waves

Oblique Whistler-Mode Waves in the Earth’s Inner Magnetosphere: Energy Distribution, Origins, and Role in Radiation Belt Dynamics

Empirical model of lower band chorus wave distribution in the outer radiation belt

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