EMIC‐Wave Driven Electron Precipitation Observed by CALET on the International Space Station

Bruno, A.; Blum, L. W.; Nolfo, G. A. de; Kataoka, Ryuho; Torii, Shoji; Greeley, A. D.; Kanekal, S.; Ficklin, Anthony W.; Guzik, T. G.; Nakahira, S.

doi:10.1029/2021gl097529

Cited by 16 publications

(18 citation statements)

References 47 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…While the calculation of minimum resonant energy typically relies on cold plasma, EMIC waves primarily contribute to the loss of >MeV electrons, even under hot plasma approximation (e.g., Bashir et al, 2022;Cao et al, 2017). Such wave-particle interaction results in a distinct EMIC waves signature, characterized by PSD minima, which has been observed in many studies (Blum et al, 2020;Bruno et al, 2022;Da Silva et al, 2021;Drozdov et al, 2017;Kim et al, 2021;Ma et al, 2020;Shprits et al, 2016;Xiang et al, 2017;Xiong et al, 2021). However, the PSD minima were also observed at energies that correspond to sub-MeV (Capannolo et al, 2019;Yan et al, 2023) suggesting that EMIC waves can also contribute to the loss of those electrons (Hendry et al, 2019(Hendry et al, , 2021Rodger et al, 2015).…”

Section: Introductionmentioning

confidence: 92%

Distribution of Seed Electron Phase Space Density Minima in Earth's Radiation Belts

Drozdov,

Allison,

Saikin

et al. 2024

Geophysical Research Letters

View full text Add to dashboard Cite

We conducted a statistical analysis of local phase space density (PSD) minima across a wide energy range (∼20 keVs to ∼10 MeV), using observations from the Van Allen Probes and the Geostationary Operational Environmental Satellite. We identified deepening minima in PSD profiles of multi‐MeV (∼5% occurrence) and of “seed” electrons (up to 15% occurrence, corresponding to ∼70–100 s keV) and compared their distribution with a 3D diffusion model using the Versatile Electron Radiation Belts (VERB) code. The comparison of the observed and modeled distributions suggests that the PSD minima of seed electrons are likely associated with hiss waves and the corresponding L‐shell dependent electron lifetimes. However, the observed distribution was not fully reproduced by the model, potentially indicating other fast loss mechanisms of seed electrons.

show abstract

Section: Introductionmentioning

confidence: 92%

Distribution of Seed Electron Phase Space Density Minima in Earth's Radiation Belts

Drozdov,

Allison,

Saikin

et al. 2024

Geophysical Research Letters

View full text Add to dashboard Cite

show abstract

“…Specifically, this analysis is based on the 1 s countrates from the two orthogonal layers of plastic scintillators constituting the charge detector (CHD), placed at the top of the apparatus, with a detection threshold corresponding to ∼1.5 MeV (CHD-X) and ∼3.4 MeV (CHD-Y) electrons, respectively. While the primary science focus of this instrument is astrophysical, sensitivity to MeV electrons enables it to be useful for radiation belt studies as well (e.g., Bruno et al, 2022;Kataoka et al, 2016Kataoka et al, , 2020Ueno et al, 2020).…”

Section: Datamentioning

confidence: 99%

On the Spatial and Temporal Evolution of EMIC Wave‐Driven Relativistic Electron Precipitation: Magnetically Conjugate Observations From the Van Allen Probes and CALET

Blum,

Bruno,

Capannolo

et al. 2024

Geophysical Research Letters

Self Cite

View full text Add to dashboard Cite

Electromagnetic ion cyclotron (EMIC) waves have been shown to be able to drive strong electron precipitation, particularly at MeV energies. However, the spatio‐temporal evolution of both the waves and the resulting precipitation is still not well understood. Here we investigate the evolution of relativistic electron precipitation driven by EMIC waves through combined observations from the Van Allen Probes and the CALorimetric Electron Telescope experiment onboard the International Space Station. Two case studies are examined where EMIC waves near the magnetic equator and precipitation at low altitude were detected in close magnetic conjunction, both of which were confined to narrow radial regions but persisted multiple hours. These observations, combined with quasilinear calculations, confirm that long‐lived EMIC waves can drive hours‐long MeV electron precipitation loss. However, the magnitude of the precipitation varied significantly during one of the events, as resonance conditions, particularly plasma density, evolved.

show abstract

“…For instance, magnetopause shadowing (Staples et al, 2022;West et al 1972) coupled with outward radial diffusion driven by Ultra Low Frequency (ULF) waves (e.g., Turner et al, 2012) can drive rapid losses of electrons. At the same time wave-particle interactions driven by Very Low Frequency (VLF) Chorus and Hiss waves (e.g., Breneman et al, 2015;Halford et al, 2022;O'Brien et al, 2004), electromagnetic ion cyclotron waves (EMIC) (e.g., Bingley et al, 2019;Bruno et al, 2022), ULF waves (e.g., Brito et al, 2015;, and kinetic Alfven (e.g., Chaston et al, 2018) waves can enhance electron precipitation across a wide range of energies leading to a loss of radiation belt electrons. Further, enhanced convection and substorm injections can replenish lower energy electrons providing pathway for the excitation of whistler mode chorus which can rapidly accelerate electrons to relativistic (several MeV) energies (Horne 2003;Horne and Thorne 1998;Horne et al 2005;Thorne et al, 2013) creating peaks in electron phase space density (Reeves et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

A New Four-Component L*-dependent Model for Radial Diffusion based on Solar Wind and Magnetospheric Drivers of ULF Waves

Murphy

Sandhu

Rae

et al. 2023

Preprint

View full text Add to dashboard Cite

Waves which couple to energetic electrons are particularly important in space weather, as they drive rapid changes in the topology and intensity of Earth’s outer radiation belt during geomagnetic storms. This includes Ultra Low Frequency (ULF) waves that interact with electrons via radial diffusion which can lead to electron dropouts and rapid acceleration and inward transport of electrons during. In radiation belt simulations, the strength of this interaction is specified by ULF wave radial diffusion coefficients. In this paper we detail the development of new models of electric and magnetic radial diffusion coefficients derived from in-situ observations of the azimuthal electric field and compressional magnetic field. The new models use L* as it accounts for adiabatic changes due to the dynamic magnetic field coupled with an optimized set of four components of solar wind and geomagnetic activity, Bz, V, Pdyn and Sym-H, as independent variables (inputs). These independent variables are known drivers of ULF waves and offer the ability to calculate diffusion coefficients at a higher cadence then existing models based on Kp. We investigate the performance of the new models by characterizing the model residuals as a function of each independent variable and by comparing to existing radial diffusion models during a quiet geomagnetic period and through a geomagnetic storm. We find that the models developed here perform well under varying levels of activity and have a larger slope or steeper gradient as a function of L* as compared to existing models (higher radial diffusion at higher L* values).

show abstract

EMIC‐Wave Driven Electron Precipitation Observed by CALET on the International Space Station

Cited by 16 publications

References 47 publications

Distribution of Seed Electron Phase Space Density Minima in Earth's Radiation Belts

Distribution of Seed Electron Phase Space Density Minima in Earth's Radiation Belts

On the Spatial and Temporal Evolution of EMIC Wave‐Driven Relativistic Electron Precipitation: Magnetically Conjugate Observations From the Van Allen Probes and CALET

A New Four-Component L*-dependent Model for Radial Diffusion based on Solar Wind and Magnetospheric Drivers of ULF Waves

Contact Info

Product

Resources

About