Rapid precipitation of radiation belt electrons induced by EMIC rising tone emissions localized in longitude inside and outside the plasmapause

Kubota, Yukiho; Omura, Yoshiharu

doi:10.1002/2016ja023267

Cited by 68 publications

(130 citation statements)

References 25 publications

(81 reference statements)

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“…In addition, Kubota and Omura (2017) have suggested that the precipitation of relativistic electrons is caused through two processes: the nonlinear wave trapping at large pitch angles and SLPA (scattering at low pitch angle) at small pitch angles. SLPA causes a strong scattering and precipitation for small pitch angle electrons without nonlinear wave trapping.…”

Section: 1029/2019ja026772mentioning

confidence: 99%

“…SLPA causes a strong scattering and precipitation for small pitch angle electrons without nonlinear wave trapping. Based on the discussion in Kubota and Omura (2017), SLPA condition of a pitch angle α is Combined with the SLPA effect at low pitch angles, the relativistic electrons precipitate in several seconds.…”

Section: 1029/2019ja026772mentioning

confidence: 99%

“…Kubota and Omura (2017) have demonstrated that interactions between electrons and an EMIC rising tone (10-s element) in localized equatorial range 10°in longitude generate drift echoes of depletion in the electron flux. When we assume B w = 10 nT and B 0 = 200 nT, SLPA can take place for the electrons with α≤20°.…”

Section: 1029/2019ja026772mentioning

confidence: 99%

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Rapid Precipitation of Relativistic Electron by EMIC Rising‐Tone Emissions Observed by the Van Allen Probes

et al. 2019

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On 23 February 2014, Van Allen Probes sensors observed quite strong electromagnetic ion cyclotron (EMIC) waves in the outer dayside magnetosphere. The maximum amplitude was more than 14 nT, comparable to 7% of the magnitude of the ambient magnetic field. The EMIC waves consisted of a series of coherent rising tone emissions. Rising tones are excited sporadically by energetic protons. At the same time, the probes detected drastic fluctuations in fluxes of MeV electrons. It was found that the electron fluxes decreased by more than 30% during the 1 min following the observation of each EMIC rising tone emissions. Furthermore, it is concluded that the flux reduction is a nonadiabatic (irreversible) process since holes in the particle flux levels appear as drift echoes with energy dispersion. We examine the process of electron pitch angle scattering by nonlinear wave trapping due to anomalous cyclotron resonance with EMIC rising tone emissions. The energy range of precipitated electrons agrees with the presumed energy for the threshold amplitude for nonlinear wave trapping. This is the first report of rapid precipitation (<1 min) of relativistic electrons by EMIC rising tone emissions and their drift echoes in time observed by spacecraft.

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Section: 1029/2019ja026772mentioning

confidence: 99%

Section: 1029/2019ja026772mentioning

confidence: 99%

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Rapid Precipitation of Relativistic Electron by EMIC Rising‐Tone Emissions Observed by the Van Allen Probes

et al. 2019

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“…Nonlinear interaction of relativistic electrons with a model EMIC wave packet, corresponding to the emission with rising frequency, has been studied through theoretical analysis and test particle simulations in Grach and Demekhov (, ), Kubota and Omura (), and Omura & Zhao (, ). Kubota and Omura () showed that combined scattering process of the nonlinear wave trapping and another nonlinear regime “SLPA” (scattering at low pitch angle) can lead to the rapid loss of relativistic electrons. The authors explained “SLPA” regime by the Lorentz force term in the equation for the particle phase (hereafter termed force bunching).…”

Section: Introductionmentioning

confidence: 99%

Precipitation of Relativistic Electrons Under Resonant Interaction With Electromagnetic Ion Cyclotron Wave Packets

Grach

Демехов

2020

JGR Space Physics

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We use numerical simulations to study the resonant interaction of relativistic electrons with rising‐frequency electromagnetic ion cyclotron (EMIC) wave packets in the normalH+ band. We find that precipitating fluxes are formed by quasi‐linear interaction and several nonlinear interaction regimes having opposite effects. In particular, the direct influence of Lorentz force on the particle phase (force bunching) decreases precipitation for particles with low equatorial pitch angles (up to 15–25°) and can even block it completely. Four other nonlinear regimes are possible: nonlinear shift of the resonance point, which can cause pitch angle drift in both directions; phase bunching that slightly increases pitch angle for untrapped particles; directed scattering that strongly decreases pitch angle for untrapped particles; and particle trapping by the wave field that decreases pitch angle. The evolution of the equatorial pitch angle distribution during several passes of particles through the wave packet is studied. The precipitating fluxes are evaluated and compared with theoretical estimates. We show that strong diffusion limit is maintained for a certain range of energies by a wave packet with realistic amplitude and frequency drift. In this case, the quasi‐linear theory strongly underestimates the precipitating flux. With increasing energy, the precipitating fluxes decrease and become close to the quasi‐linear estimates.

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“…Exotic, but real process is the electron precipitation due to parasitic resonance with electromagnetic ioncyclotron (EMIC) waves [Summers, Thorne, 2003;Lazutin et al, 2011;Kubota, Omura, 2017]. EMIC waves are generated by ring current protons during the storm main phase.…”

Section: Interaction Of Electrons With High-frequency Wavesmentioning

confidence: 99%

Electron radiation belt dynamics during magnetic storms and in quiet time

Lazutin¹,

Дмитриев²,

Дмитриев

et al. 2018

Solar-Terrestrial Physics

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Abstract. The paper discusses the outer electron belt dynamics, adiabatic and nonadiabatic mechanisms of increases and losses of energetic electrons.Under undisturbed conditions, the outer electron belt gradually empties: in the inner magnetosphere due to electron losses in the atmosphere and in the quasitrapping region due to losses at the magnetopause because drift shells of electrons are not closed there. The latter process does not occur in normal years due to the masking replenishment by freshly accelerated particles, but in years of extremely low activity it leads to a significant decrease in the electron population of the belt.During the magnetic storm main phase, the first reason for the decrease in the electron flux intensity is the adiabatic cooling associated with conservation of adiabatic invariants and complemented by injection of electrons into the atmosphere and their losses at the magnetopause. Electron flux increases involve E×B electron injection by the induction electric field of substorm activation and by the large-scale solar wind electric field, with pitch energy diffusion along with adiabatic heating in the recovery phase.The rate of electron flux recovery after a storm is determined by the ratio of nonadiabatic increases and losses; hence the electron flux represents a continuous series from low to very high values. The combination of these processes determines the individual character of radiation belt development during each magnetic storm and the behavior of the belt in the quiet time.

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Rapid precipitation of radiation belt electrons induced by EMIC rising tone emissions localized in longitude inside and outside the plasmapause

Cited by 68 publications

References 25 publications

Rapid Precipitation of Relativistic Electron by EMIC Rising‐Tone Emissions Observed by the Van Allen Probes

Rapid Precipitation of Relativistic Electron by EMIC Rising‐Tone Emissions Observed by the Van Allen Probes

Precipitation of Relativistic Electrons Under Resonant Interaction With Electromagnetic Ion Cyclotron Wave Packets

Electron radiation belt dynamics during magnetic storms and in quiet time

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