Energetic Electron Precipitation: Multievent Analysis of Its Spatial Extent During EMIC Wave Activity

Capannolo, L.; Li, W.; Ma, Q.; Shen, Xiaochen; Zhang, X.‐J.; Redmon, R. J.; Rodriguez, J. V.; Engebretson, M. J.; Kletzing, C. A.; Kurth, W. S.; Hospodarsky, G. B.; Spence, H. E.; Reeves, G. D.; Raita, Tero

doi:10.1029/2018ja026291

Cited by 63 publications

(85 citation statements)

References 78 publications

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“…While precipitating protons can produce proton aurora Yuan et al, 2010),~MeV electrons can interact with atmospheric nitrogen and hydrogen oxides, leading to ozone reduction (e.g., Meraner & Schmidt, 2018). The efficacy of EMIC waves in scattering MeV electrons and ring current protons has been confirmed in multiple studies, both observationally and theoretically (Blum et al, 2015;Capannolo et al, 2018Capannolo et al, , 2019Hirai et al, 2018;Qin et al, 2018Qin et al, , 2019Shekhar et al, 2017;Woodger et al, 2018;Yuan et al, 2018). However, the techniques and the satellites used have limitations that still leave a few open questions, for example, on the minimum energy of electrons (E min ) that can be scattered into the loss cone.…”

Section: 1029/2019gl084202mentioning

confidence: 96%

Direct Observation of Subrelativistic Electron Precipitation Potentially Driven by EMIC Waves

Capannolo

et al. 2019

Geophysical Research Letters

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Electromagnetic ion cyclotron (EMIC) waves are known to typically cause electron losses into Earth's upper atmosphere at >~1 MeV, while the minimum energy of electrons subject to efficient EMIC‐driven precipitation loss is unresolved. This letter reports electron precipitation from subrelativistic energies of ~250 keV up to ~1 MeV observed by the Focused Investigations of Relativistic Electron Burst Intensity, Range and Dynamics (FIREBIRD‐II) CubeSats, while two Polar Operational Environmental Satellites (POES) observed proton precipitation nearby. Van Allen Probe A detected EMIC waves (~0.7–2.0 nT) over the similar L shell extent of electron precipitation observed by FIREBIRD‐II, albeit with a ~1.6 magnetic local time (MLT) difference. Although plasmaspheric hiss and magnetosonic waves were also observed, quasi‐linear calculations indicate that EMIC waves were the most efficient in driving the electron precipitation. Quasi‐linear theory predicts efficient precipitation at >0.8–1 MeV (due to H‐band EMIC waves), suggesting that other mechanisms are required to explain the observed subrelativistic electron precipitation.

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Section: 1029/2019gl084202mentioning

confidence: 96%

Direct Observation of Subrelativistic Electron Precipitation Potentially Driven by EMIC Waves

Capannolo

et al. 2019

Geophysical Research Letters

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“…These waves drive considerable contemporary scientific interest, particularly during the recent Van Allen Probes mission. Many recent studies are dedicated to the loss they cause to ultrarelativistic electrons (e.g., Thorne & Kennel, ; Albert, ; Jordanova et al, ; Miyoshi et al, ; Rodger et al, , Rodger et al, ; Li et al, , 2014; Usanova et al, , ; Kersten et al, ; Blum et al, ; Clilverd et al, ; Woodger et al, , ; Colpitts et al, ; Shprits et al, , , , ; Hendry et al, , ; Zhang et al, ; Aseev et al, ; Drozdov, Shprits, Usanova, et al, ; Capannolo et al, , ; Denton et al, ; Qin et al, ), themselves related to the complex location and duration of these waves. EMIC waves are discrete electromagnetic emissions in multiple frequency bands (e.g., Saikin et al, ), which are observed across a large region of geospace (e.g., Saikin et al, ), including the ring current and the plasmasphere, dayside plumes, and the outer dayside magnetosphere (Engebretson et al, ; Engebretson et al, ; Engebretson et al, ; Tetrick et al, ).…”

Section: Particle Loss In the Inner And Outer Zonesmentioning

confidence: 99%

Particle Dynamics in the Earth's Radiation Belts: Review of Current Research and Open Questions

et al. 2020

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The past decade transformed our observational understanding of energetic particle processes in near‐Earth space. An unprecedented suite of observational systems was in operation including the Van Allen Probes, Arase, Magnetospheric Multiscale, Time History of Events and Macroscale Interactions during Substorms, Cluster, GPS, GOES, and Los Alamos National Laboratory‐GEO magnetospheric missions. They were supported by conjugate low‐altitude measurements on spacecraft, balloons, and ground‐based arrays. Together, these significantly improved our ability to determine and quantify the mechanisms that control the buildup and subsequent variability of energetic particle intensities in the inner magnetosphere. The high‐quality data from National Aeronautics and Space Administration's Van Allen Probes are the most comprehensive in situ measurements ever taken in the near‐Earth space radiation environment. These observations, coupled with recent advances in radiation belt theory and modeling, including dramatic increases in computational power, have ushered in a new era, perhaps a “golden era,” in radiation belt research. We have edited a Journal of Geophysical Research: Space Science Special Collection dedicated to Particle Dynamics in the Earth's Radiation Belts in which we gather the most recent scientific findings and understanding of this important region of geospace. This collection includes the results presented at the American Geophysical Union Chapman International Conference in Cascais, Portugal (March 2018) and many other recent and relevant contributions. The present article introduces and review the context, current research, and main questions that motivate modern radiation belt research divided into the following topics: (1) particle acceleration and transport, (2) particle loss, (3) the role of nonlinear processes, (4) new radiation belt modeling capabilities and the quantification of model uncertainties, and (5) laboratory plasma experiments.

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“…For example, Clilverd et al () showed EMIC‐induced electron precipitation with a lower cutoff energy of 280 keV. Other conjunction events have also demonstrated sub‐MeV electron precipitation driven by EMIC waves (e.g., Capannolo, Li, Ma, Shen, et al, , Capannolo, Li, Ma, Chen, et al, ; Hendry et al, ).…”

Section: Introductionmentioning

confidence: 99%

Generation and Characteristics of Unusual High Frequency EMIC Waves

Teng

Tao

et al. 2019

Geophysical Research Letters

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We report unusual Electromagnetic Ion Cyclotron (EMIC) waves with a very narrow frequency bandwidth, closely following and approaching the proton gyrofrequency. One interesting case analysis shows that magnetosonic waves, anisotropic suprathermal proton distributions, and high frequency EMIC waves are closely related. Magnetosonic waves potentially cause the resonant heating of suprathermal protons and the temperature anisotropy of suprathermal protons (10-100 eV) likely provides free energy for the excitation of high frequency EMIC waves. The statistical analysis shows that this type of EMIC waves has a typical wave amplitude of~100 pT, left-handed polarization, and small wave normal angles. Moreover, these low frequency EMIC waves typically occur near the equator in the low-density regions from dawn to dusk. These newly observed high frequency EMIC waves provide new insights into understanding the generation of EMIC waves and the energy transfer between magnetosonic waves and EMIC waves. Plain Language Summary Electromagnetic Ion Cyclotron (EMIC) waves are commonlyobserved in the Earth's magnetosphere and play an important role in causing the loss of ring current ions and relativistic electrons due to pitch angle scattering. In this study, we report unusual high frequency EMIC waves with frequency very close to the proton gyrofrequency. An interesting case study clearly shows the correlation between magnetosonic waves, the enhancement of suprathermal protons, and high frequency EMIC waves. The protons at suprathermal energies could be heated by magnetosonic waves and the anisotropic distribution of suprathermal protons is likely responsible for the excitation of high frequency EMIC waves. The statistical analysis shows that this type of EMIC waves has a typical wave amplitude of~100 pT, left-handed polarization, and small wave normal angles. These newly observed high frequency EMIC waves provide new insights into understanding the generation of EMIC waves and the energy transfer between magnetosonic waves and EMIC waves.

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Energetic Electron Precipitation: Multievent Analysis of Its Spatial Extent During EMIC Wave Activity

Cited by 63 publications

References 78 publications

Direct Observation of Subrelativistic Electron Precipitation Potentially Driven by EMIC Waves

Direct Observation of Subrelativistic Electron Precipitation Potentially Driven by EMIC Waves

Particle Dynamics in the Earth's Radiation Belts: Review of Current Research and Open Questions

Generation and Characteristics of Unusual High Frequency EMIC Waves

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