Competition between outer zone electron scattering by plasmaspheric hiss and magnetosonic waves

Ni, Binbin; Hua, Man; Zhou, Ruoxian; Yi, Juan; Fu, Song

doi:10.1002/2017gl072989

Cited by 71 publications

(79 citation statements)

References 23 publications

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“…Although EN emissions stay confined to the equatorial plane, they may propagate in radial/azimuthal directions (Chen & Thorne, ; Horne et al, ; Němec, Santolík, Pickett, Hrbáčková, et al, ; Santolík et al, ; Xiao et al, ). EN is considered to be important for electron dynamics in the Van Allen radiation belts (Bortnik et al, ; Horne et al, ; Li et al, ; Ma et al, ; Ni et al, ; Shprits, ; Walker, Balikhin, Canu, et al, ), as well as for the formation of so‐called butterfly distribution functions (Li, Bortnik, et al, ; Li, Ni, et al, ; Maldonado et al, ; Xiao, Yang, et al, ; Yang et al, ).…”

Section: Introductionmentioning

confidence: 99%

Detailed Properties of Equatorial Noise With Quasiperiodic Modulation

et al. 2018

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Equatorial noise (EN) emissions are electromagnetic waves observed routinely in the equatorial region of the inner magnetosphere. Although they are typically continuous in time, they sometimes exhibit a quasiperiodic (QP) time modulation of the wave intensity, with modulation periods on the order of minutes. We perform a detailed analysis of 118 EN events with the QP modulation. The events are observed preferentially outside the plasmasphere. We determine the times and frequencies of individual QP elements forming the events. Apart from the event modulation period, this allows us to characterize the intensity and the frequency drift of individual QP wave elements. It is shown that the element intensity peaks at the magnetic equator. The modulation period within a single event is usually quite stable, with variations lower than 25% of the median value in the vast majority of cases. The events with shorter modulation periods are typically more intense, and they tend to have larger frequency drifts. These relations resemble the relations formerly revealed for extra low frequency/very low frequency quasiperiodic emissions, suggesting that the origin of the QP modulation of the wave intensity of EN and ELF/VLF emissions might be similar.

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Section: Introductionmentioning

confidence: 99%

Detailed Properties of Equatorial Noise With Quasiperiodic Modulation

et al. 2018

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“…The high quasi-trapped electron flux levels around L = 2.5 can be explained by the scattering effect of plasmaspheric hiss and lightning generated whistler wave on trapped electrons, which have different flux levels at L = 3 and L = 2.5. This could explain the dominance of CRAND-produced quasi-trapped electrons above 300 keV at L = 3 but not at L = 2.5, where a high remaining flux of inward transported outer belt electrons can be continuously scattered toward the loss cone by lightning-generated whistler and plasmaspheric hiss waves Mourenas et al, 2017;Ni et al, 2014Ni et al, , 2017Zhao et al, 2019). The corresponding 300-700-keV electron lifetimes are about 1-2 days at L = 3 versus~5-20 days at L = 2.5.…”

Section: Energy Spectrum and L Dependence Of Crand Electron Fluxesmentioning

confidence: 98%

Modeling the Quasi‐Trapped Electron Fluxes From Cosmic Ray Albedo Neutron Decay (CRAND)

Xiang

Selesnick

et al. 2019

Geophysical Research Letters

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Recently, cosmic ray albedo neutron decay (CRAND) has been identified as the main source of relativistic electrons measured at the inner edge of inner radiation belt. Here we introduce a drift‐source model that includes azimuthal drift and a CRAND electron source to simulate the quasi‐trapped electron distribution measured by the DEMETER satellite during 20–30 April 2010. The simulated longitude distribution of quasi‐trapped electron fluxes at the inner edge of inner radiation belt successfully reproduces the DEMETER observations, confirming CRAND as the main source for these electrons. Furthermore, a comparison of the energy spectrum and the L distribution of the quasi‐trapped relativistic electrons between simulations and observations further suggests that CRAND is likely the dominant source for 300–700‐keV quasi‐trapped electrons at L < 2 and L ≈ 3.

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“…Such two‐peak particle distributions are not realistic, because other waves, such as hiss waves, which usually coexist with the MS waves outside the plasmasphere and play a role in scattering the electrons by forming the butterfly distributions at large pitch angles (Li, Bortnik, et al, ), would smooth these two‐peak distributions (Ni et al, ). Our simulations imply that the MS waves can produce energetic electron butterfly distributions more likely inside the plasmapause.…”

Section: Electron Diffusion Simulationmentioning

confidence: 99%

The Radiation Belt Electron Scattering by Magnetosonic Wave: Dependence on Key Parameters

Lei

Xie

et al. 2017

JGR Space Physics

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Magnetosonic (MS) waves have been found capable of creating radiation belt electron butterfly distributions in the inner magnetosphere. To investigate the physical nature of the interactions between radiation belt electrons and MS waves, and to explore a preferential condition for MS waves to scatter electrons efficiently, we performed a comprehensive parametric study of MS wave‐electron interactions using test particle simulations. The diffusion coefficients simulated by varying the MS wave frequency show that the scattering effect of MS waves is frequency insensitive at low harmonics (f < 20 fcp), which has great implications on modeling the electron scattering caused by MS waves with harmonic structures. The electron scattering caused by MS waves is very sensitive to wave normal angles, and MS waves with off 90° wave normal angles scatter electrons more efficiently. By simulating the diffusion coefficients and the electron phase space density evolution at different L shells under different plasma environment circumstances, we find that MS waves can readily produce electron butterfly distributions in the inner part of the plasmasphere where the ratio of electron plasma‐to‐gyrofrequency (fpe/fce) is large, while they may essentially form a two‐peak distribution outside the plasmapause and in the inner radiation belt where fpe/fce is small.

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Competition between outer zone electron scattering by plasmaspheric hiss and magnetosonic waves

Cited by 71 publications

References 23 publications

Detailed Properties of Equatorial Noise With Quasiperiodic Modulation

Detailed Properties of Equatorial Noise With Quasiperiodic Modulation

Modeling the Quasi‐Trapped Electron Fluxes From Cosmic Ray Albedo Neutron Decay (CRAND)

The Radiation Belt Electron Scattering by Magnetosonic Wave: Dependence on Key Parameters

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