Journal article
Van Allen Probes Observations of Multi‐MeV Electron Drift‐Periodic Flux Oscillations in Earth's Outer Radiation Belt During the March 2017 Event
Journal of geophysical research. Space physics, Vol.126(8), e2021JA029284
08/2021
DOI: 10.1029/2021JA029284
Abstract
Radiation belt electrons undergo frequent acceleration, transport, and loss processes under various physical mechanisms. One of the most prevalent mechanisms is radial diffusion, caused by the resonant interactions between energetic electrons and ULF waves in the Pc4‐5 band. An indication of this resonant interaction is believed to be the appearance of periodic flux oscillations. In this study, we report long‐lasting, drift‐periodic flux oscillations of relativistic and ultrarelativistic electrons with energies up to ∼7.7 MeV in the outer radiation belt, observed by the Van Allen Probes mission. During this March 2017 event, multi‐MeV electron flux oscillations at the electron drift frequency appeared coincidently with enhanced Pc5 ULF wave activity and lasted for over 10 h in the center of the outer belt. The amplitude of such flux oscillations is well correlated with the radial gradient of electron phase space density (PSD), with almost no oscillation observed near the PSD peak. The temporal evolution of the PSD radial profile also suggests the dominant role of radial diffusion in multi‐MeV electron dynamics during this event. By combining these observations, we conclude that these multi‐MeV electron flux oscillations are caused by the resonant interactions between electrons and broadband Pc5 ULF waves and are an indicator of the ongoing radial diffusion process during this event. They contain essential information of radial diffusion and have the potential to be further used to quantify the radial diffusion effects and aid in a better understanding of this prevailing mechanism.
Key Points
Long‐lasting, drift‐periodic flux oscillations of 1.8–7.7 MeV electrons in the radiation belt are reported using Van Allen Probes data
Flux oscillations appeared coincidently with enhanced Pc5 ULF waves with amplitude well correlated with phase space density radial gradient
These flux oscillations indicate the resonant interactions between electrons and broadband Pc5 ULF waves
Details
- Title: Subtitle
- Van Allen Probes Observations of Multi‐MeV Electron Drift‐Periodic Flux Oscillations in Earth's Outer Radiation Belt During the March 2017 Event
- Creators
- Hong Zhao - Auburn UniversityTheodore E. Sarris - Democritus University of ThraceXinlin Li - University of Colorado BoulderMax Weiner - University of Colorado BoulderIsabela G. Huckabee - Arizona State UniversityDaniel N. Baker - Laboratory for Atmospheric and Space PhysicsAllison J. Jaynes - University of IowaShrikanth G. Kanekal - Goddard Space Flight CenterScot R. Elkington - University of Colorado BoulderMohammad Barani - West Virginia UniversityWeichao Tu - West Virginia UniversityWenlong Liu - Beihang UniversityDianjun Zhang - Beihang UniversityMichael D. Hartinger - Space Science Institute
- Resource Type
- Journal article
- Publication Details
- Journal of geophysical research. Space physics, Vol.126(8), e2021JA029284
- DOI
- 10.1029/2021JA029284
- ISSN
- 2169-9380
- eISSN
- 2169-9402
- Number of pages
- 16
- Grant note
- National Aeronautics and Space Administration (NASA) (80NSSC18K1284; 80NSSC19M0146; 80NSSC18K1613) High Altitude Observatory Newkirk Fellowship National Science Foundation (NSF) (AGS 1952903; AGS 1852977; AGS 1752736) RBSP‐ECT
- Language
- English
- Date published
- 08/2021
- Academic Unit
- Physics and Astronomy; University College Courses
- Record Identifier
- 9984429047702771
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