Found 7 results
Filters: Keyword is Electron scattering  [Clear All Filters]
Authors: Zhang Wenxun, Ni Binbin, Huang He, Summers Danny, Fu Song, et al.
Title: Statistical Properties of Hiss in Plasmaspheric Plumes and Associated Scattering Losses of Radiation Belt Electrons
Abstract: Whistler mode hiss acts as an important loss mechanism contributing to the radiation belt electron dynamics inside the plasmasphere and plasmaspheric plumes. Based on Van Allen Probes observations from September 2012 to December 2015, we conduct a detailed analysis of hiss properties in plasmaspheric plumes and illustrate that corresponding to the highest occurrence probability of plumes at L = 5.0–6.0 and MLT = 18–21, hiss emissions occur concurrently with a rate of >~80%. Plume hiss can efficiently scatter ~10‐ to 100‐keV electrons at rates up to ~10−4 s−1 near the loss cone, and the resultant electron loss timescales vary largely with energy, that is, from less than an hour for tens of kiloelectron volt electrons to several days for hundreds of kiloelectron volt electrons an. . .
Date: 05/2019 Publisher: Geophysical Research Letters DOI: 10.1029/2018GL081863 Available at:
More Details
Authors: Zhang Wenxun, Fu Song, Gu Xudong, Ni Binbin, Xiang Zheng, et al.
Title: Electron Scattering by Plasmaspheric Hiss in a Nightside Plume
Abstract: Plasmaspheric hiss is known to play an important role in radiation belt electron dynamics in high plasma density regions. We present observations of two crossings of a plasmaspheric plume by the Van Allen Probes on 26 December 2012, which occurred unusually at the post‐midnight‐to‐dawn sector between L ~ 4–6 during a geomagnetically quiet period. This plume exhibited pronounced electron densities higher than those of the average plume level. Moderate hiss emissions accompanied the two plume crossings with the peak power at about 100 Hz. Quantification of quasi‐linear bounce‐averaged electron scattering rates by hiss in the plume demonstrates that the waves are efficient to pitch angle scatter ~10–100 keV electrons at rates up to ~10−4 s−1 near the loss cone but become gra. . .
Date: 05/2018 Publisher: Geophysical Research Letters DOI: 10.1029/2018GL077212 Available at:
More Details
Authors: Ma Qianli, Mourenas Didier, Li Wen, Artemyev Anton, and Thorne Richard M
Title: VLF waves from ground-based transmitters observed by the Van Allen Probes: Statistical model and effects on plasmaspheric electrons
Abstract: Whistler-mode Very Low Frequency (VLF) waves from powerful ground-based transmitters can resonantly scatter energetic plasmaspheric electrons and precipitate them into the atmosphere. A comprehensive 4-year statistics of Van Allen Probes measurements is carried out to assess their consequences on the dynamics of the inner radiation belt and slot region. Statistical models of the measured wave electric field power and of the inferred full wave magnetic amplitude are provided as a function of L, magnetic local time, season, and Kp over L=1-3, revealing the localization of VLF wave intensity and its variation with geomagnetic activity over 2012-2016. Since this VLF wave model can be directly used together with existing hiss and lightning-generated wave models in radiation belt simulation code. . .
Date: 06/2017 Publisher: Geophysical Research Letters DOI: 10.1002/2017GL073885 Available at:
More Details
Authors: Artemyev A. V., Agapitov O. V., Mozer F S, and Spence H.
Title: Butterfly pitch-angle distribution of relativistic electrons in the outer radiation belt: Evidence of nonadiabatic scattering
Abstract: In this paper we investigate the scattering of relativistic electrons in the night-side outer radiation belt (around the geostationary orbit). We consider the particular case of low geomagnetic activity (|Dst|< 20 nT), quiet conditions in the solar wind, and absence of whistler wave emissions. For such conditions we find several events of Van-Allen probe observations of butterfly pitch-angle distributions of relativistic electrons (energies about 1-3 MeV). Many previous publications have described such pitch-angle distributions over a wide energy range as due to the combined effect of outward radial diffusion and magnetopause shadowing. In this paper we discuss another mechanism that produces butterfly distributions over a limited range of electron energies. We suggest that such distributi. . .
Date: 05/2015 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2014JA020865 Available at:
More Details
Authors: Ma Qianli, Li Wen, Thorne Richard M, Bortnik Jacob, Kletzing C A, et al.
Title: Electron scattering by magnetosonic waves in the inner magnetosphere
Abstract: We investigate the importance of electron scattering by magnetosonic waves in the Earth's inner magnetosphere. A statistical survey of the magnetosonic wave amplitude and wave frequency spectrum, as a function of geomagnetic activity, is performed using the Van Allen Probes wave measurements, and is found to be generally consistent with the wave distribution obtained from previous spacecraft missions. Outside the plasmapause the statistical frequency distribution of magnetosonic waves follows the variation of the lower hybrid resonance frequency, but this trend is not observed inside the plasmasphere. Drift and bounce averaged electron diffusion rates due to magnetosonic waves are calculated using a recently developed analytical formula. The resulting time scale of electron energization du. . .
Date: 12/2015 Publisher: Journal of Geophysical Research: Space Physics DOI: 10.1002/2015JA021992 Available at:
More Details
Authors: Spasojevic M., Shprits Y.Y., and Orlova K.
Title: Global Empirical Models of Plasmaspheric Hiss using Van Allen Probes
Abstract: Plasmaspheric hiss is a whistler mode emission that permeates the Earth's plasmasphere and is a significant driver of energetic electron losses through cyclotron-resonant pitch angle scattering. The EMFISIS instrument on the Van Allen Probes mission provides vastly improved measurements of the hiss wave environment including continuous measurements of the wave magnetic field cross-spectral matrix and enhanced low frequency coverage. Here, we develop empirical models of hiss wave intensity using two years of Van Allen Probes data. First, we describe the construction of the hiss database. Then, we compare the hiss spectral distribution and integrated wave amplitude obtained from Van Allen Probes to those previously extracted from the CRRES mission. Next, we develop a cubic regression model o. . .
Date: 11/2015 Publisher: Journal of Geophysical Research: Space Physics Pages: n/a - n/a DOI: 10.1002/2015JA021803 Available at:
More Details
Authors: Khazanov G., Sibeck D., Tel'nikhin A., and Kronberg T.
Title: Relativistic electron precipitation events driven by electromagnetic ion-cyclotron waves
Abstract: We adopt a canonical approach to describe the stochastic motion of relativistic belt electrons and their scattering into the loss cone by nonlinear EMIC waves. The estimated rate of scattering is sufficient to account for the rate and intensity of bursty electron precipitation. This interaction is shown to result in particle scattering into the loss cone, forming ∼10 s microbursts of precipitating electrons. These dynamics can account for the statistical correlations between processes of energization, pitch angle scattering, and relativistic electron precipitation events, that are manifested on large temporal scales of the order of the diffusion time ∼tens of minutes.
Date: 08/2014 Publisher: Physics of Plasmas Pages: 082901 DOI: 10.1063/1.4892185 Available at:
More Details