Journal article
Lifetimes of Relativistic Electrons as Determined From Plasmaspheric Hiss Scattering Rates Statistics: Effects of ωpe/Ωce and Wave Frequency Dependence on Geomagnetic Activity
Geophysical research letters, Vol.47(13), e2020GL088052
07/16/2020
DOI: 10.1029/2020GL088052
Abstract
Whistler‐mode hiss waves generally determine MeV electron lifetimes inside the plasmasphere. We use Van Allen Probes measurements to provide the first comprehensive statistical survey of plasmaspheric hiss‐driven quasi‐linear pitch‐angle diffusion rates and lifetimes of MeV electrons as a function of L*, local time, and AE index, taking into account hiss power, electron plasma frequency to gyrofrequency ratio ωpe/Ωce, hiss frequency at peak power ωm, and cross correlations of these parameters. We find that during geomagnetically active periods with hiss observations, ωpe/Ωce and ωm decrease, leading to faster electron loss. We demonstrate that spatiotemporal variations of ωm and ωpe/Ωce with AE, together with wave power changes, significantly affect MeV electron loss, potentially leading to short lifetimes of less than 1 day. A parametric model of MeV electron lifetime driven by AE for L > 2.5 up to the plasmapause is developed and validated using Magnetic Electron Ion Spectrometer (MagEIS) electron flux decay database.
Key Points
Statistical maps of plasmaspheric hiss wave power and frequency, plasma density are provided based on Van Allen Probes 2012–2018 EMFISIS data
MeV electron lifetimes decrease ~1.5–2 times during disturbed periods due to decreased ωpe/Ωce as compared with statistical average values
A MeV electron lifetime model (including hiss amplitude, frequency, ωpe/Ωce) is presented and validated with the MagEIS electron lifetime database
Details
- Title: Subtitle
- Lifetimes of Relativistic Electrons as Determined From Plasmaspheric Hiss Scattering Rates Statistics: Effects of ωpe/Ωce and Wave Frequency Dependence on Geomagnetic Activity
- Creators
- O. Agapitov - University of California, BerkeleyD. Mourenas - CEA DAM Île-de-FranceA. Artemyev - University of California, Los AngelesS. G. Claudepierre - University of California, Los AngelesG. Hospodarsky - University of IowaJ. W. Bonnell - University of California, Berkeley
- Resource Type
- Journal article
- Publication Details
- Geophysical research letters, Vol.47(13), e2020GL088052
- DOI
- 10.1029/2020GL088052
- ISSN
- 0094-8276
- eISSN
- 1944-8007
- Number of pages
- 10
- Grant note
- National Aeronautics and Space Administration (NASA) (80NSSC20K021; 80NSSC19K0264; NNX16AF85G S004)
- Language
- English
- Date published
- 07/16/2020
- Academic Unit
- Physics and Astronomy
- Record Identifier
- 9984455545502771
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