Modulation of Energetic Electron Precipitation Driven by Three Types of Whistler Mode Waves

Shen, Xiaochen; Li, W.; Capannolo, L.; Ma, Q.; Qin, Murong; Artemyev, А. V.; Angelopoulos, Vassilis; Zhang, Xiaojia; Huang, Sheng

doi:10.1029/2022gl101682

Cited by 8 publications

(5 citation statements)

References 64 publications

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“…The median precipitation ratio (Figure 4a–4d) steeply decreases with increasing energy from 60 keV to ∼200–300 keV, with a precipitation ratio of ∼0.1 at 60 keV and only 0.01 at 200–300 keV. This feature is consistent with chorus‐driven precipitation (e.g., Ma et al., 2020; Ni et al., 2011; Shen et al., 2023), indicating significant contributions from both dayside and nightside chorus waves. In contrast, for energies above ∼200–300 keV, the median precipitation ratio quickly drops down to 0 for all MLT sectors at L > 6.…”

Section: Statistical Resultssupporting

confidence: 75%

Global Survey of Energetic Electron Precipitation at Low Earth Orbit Observed by ELFIN

Qin,

Li,

Shen

et al. 2024

Geophysical Research Letters

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We statistically evaluate the global distribution and energy spectrum of electron precipitation at low‐Earth‐orbit, using unprecedented pitch‐angle and energy resolved data from the Electron Losses and Fields INvestigation CubeSats. Our statistical results indicate that during active conditions, the ∼63 keV electron precipitation ratio peaks at L > 6 at midnight, whereas the spatial distribution of precipitating energy flux peaks between the dawn and noon sectors. ∼1 MeV electron precipitation ratio peaks near midnight at L > ∼6 but is enhanced near dusk during active times. The energy spectrum of the precipitation ratio shows reversal points indicating energy dispersion as a function of L shell in both the slot region and at L > ∼6, consistent with hiss‐driven precipitation and current sheet scattering, respectively. Our findings provide accurate quantification of electron precipitation at various energies in a broad region of the Earth's magnetosphere, which is critical for magnetosphere‐ionosphere coupling.

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Section: Statistical Resultssupporting

confidence: 75%

Global Survey of Energetic Electron Precipitation at Low Earth Orbit Observed by ELFIN

Qin,

Li,

Shen

et al. 2024

Geophysical Research Letters

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“…We plan to use BERI to quantify the atmospheric ionization rates due to EMIC waves using ELFIN, overcoming the need to model the precipitating flux (Ma et al, 2022;Sanchez et al, 2022). Finally, this work joins previous analyses successfully conducted using CubeSat data (FIREBIRD: Breneman et al, 2017;Crew et al, 2016;Capannolo et al, 2021;Duderstadt et al, 2021;Johnson et al, 2021;Shumko et al, 2018;AC6: Shumko, Johnson, Sample, et al, 2020;ELFIN: An et al, 2022;Artemyev et al, 2022;Gan et al, 2023;Grach et al, 2022;Mourenas et al, 2021Mourenas et al, , 2022Shen et al, 2023;Zhang et al, 2022; see also Spence et al, 2022 for a review), demonstrating the remarkable assets these low-budget and educational missions bring to the field.…”

Section: Discussionmentioning

confidence: 76%

Electron Precipitation Observed by ELFIN Using Proton Precipitation as a Proxy for Electromagnetic Ion Cyclotron (EMIC) Waves

Capannolo,

Li,

et al. 2023

Geophysical Research Letters

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Electromagnetic ion cyclotron (EMIC) waves can drive radiation belt depletion and Low‐Earth Orbit satellites can detect the resulting electron and proton precipitation. The ELFIN (Electron Losses and Fields InvestigatioN) CubeSats provide an excellent opportunity to study the properties of EMIC‐driven electron precipitation with much higher energy and pitch‐angle resolution than previously allowed. We collect EMIC‐driven electron precipitation events from ELFIN observations and use POES (Polar Orbiting Environmental Satellites) to search for 10s–100s keV proton precipitation nearby as a proxy of EMIC wave activity. Electron precipitation mainly occurs on localized radial scales (∼0.3 L), over 15–24 MLT and 5–8 L shells, stronger at ∼MeV energies and weaker down to ∼100–200 keV. Additionally, the observed loss cone pitch‐angle distribution agrees with quasilinear predictions at ≳250 keV (more filled loss cone with increasing energy), while additional mechanisms are needed to explain the observed low‐energy precipitation.

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“…High-quality wave observations made near the geomagnetic equator by the Van Allen Probes found no evidence of whistler mode waves causing the scattering, only the EMIC waves seen at the spacecraft. Shen et al (2023) undertook a simulation of loss cone filling by whistler-mode chorus emissions that resulted in loss cone filling at energies from 5 to 500 keV even with very weak waves (<20 pT). Therefore, it may be possible that the unexplained IDP fluxes at <150 keV shown in Figure 6 could have been caused by the presence of undetected, weak whistler waves.…”

Section: Discussionmentioning

confidence: 99%

“…Shen et al. (2023) undertook a simulation of loss cone filling by whistler‐mode chorus emissions that resulted in loss cone filling at energies from 5 to 500 keV even with very weak waves (<20 pT). Therefore, it may be possible that the unexplained IDP fluxes at <150 keV shown in Figure 6 could have been caused by the presence of undetected, weak whistler waves.…”

Section: Discussionmentioning

confidence: 99%

Improved Energy Resolution Measurements of Electron Precipitation Observed During an IPDP‐Type EMIC Event

Clilverd,

Rodger,

Hendry

et al. 2024

JGR Space Physics

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High energy resolution DEMETER satellite observations from the Instrument for the Detection of Particle (IDP) are analyzed during an electromagnetic ion cyclotron (EMIC)‐induced electron precipitation event. Analysis of an Interval Pulsation with Diminishing Periods (IPDP)‐type EMIC wave event, using combined satellite observations to correct for incident proton contamination, detected an energy precipitation spectrum ranging from ∼150 keV to ∼1.5 MeV. While inconsistent with many theoretical predictions of >1 MeV EMIC‐induced electron precipitation, the finding is consistent with an increasing number of experimentally observed events detected using lower resolution integral channel measurements on the POES, FIREBIRD, and ELFIN satellites. Revised and improved DEMETER differential energy fluxes, after correction for incident proton contamination shows that they agree to within 40% in peak flux magnitude, and 85 keV (within 40%) for the energy at which the peak occurred as calculated from POES integral channel electron precipitation measurements. This work shows that a subset of EMIC waves found close to the plasmapause, that is, IPDP‐type rising tone events, can produce electron precipitation with peak energies substantially below 1 MeV. The rising tone features of IPDP EMIC waves, along with the association with the high cold plasma density regime, and the rapidly varying electron density gradients of the plasmapause may be an important factor in the generation of such low energy precipitation, co‐incident with a high energy tail. Our work highlights the importance of undertaking proton contamination correction when using the high‐resolution DEMETER particle measurements to investigate EMIC‐driven electron precipitation.

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Modulation of Energetic Electron Precipitation Driven by Three Types of Whistler Mode Waves

Cited by 8 publications

References 64 publications

Global Survey of Energetic Electron Precipitation at Low Earth Orbit Observed by ELFIN

Global Survey of Energetic Electron Precipitation at Low Earth Orbit Observed by ELFIN

Electron Precipitation Observed by ELFIN Using Proton Precipitation as a Proxy for Electromagnetic Ion Cyclotron (EMIC) Waves

Improved Energy Resolution Measurements of Electron Precipitation Observed During an IPDP‐Type EMIC Event

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