| Autor: |
Mourenas, D., Artemyev, A. V., Zhang, X.‐J., Angelopoulos, V. |
| Předmět: |
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| Zdroj: |
Journal of Geophysical Research. Space Physics; Nov2022, Vol. 127 Issue 11, p1-30, 30p |
| Abstrakt: |
Electron diffusion by whistler‐mode chorus waves is one of the key processes controlling the dynamics of relativistic electron fluxes in the Earth's radiation belts. It is responsible for the acceleration of sub‐relativistic electrons injected from the plasma sheet to relativistic energies as well as for their precipitation and loss into the atmosphere. Based on analytical estimates of chorus wave‐driven quasi‐linear electron energy and pitch‐angle diffusion rates, we provide analytical steady‐state solutions to the corresponding Fokker‐Planck equation for the relativistic electron distribution and flux. The impact on these steady‐state solutions of additional electromagnetic ion cyclotron waves, and of ultralow frequency waves are examined. Such steady‐state solutions correspond to hard energy spectra at 1–4 MeV, dangerous for satellite electronics, and represent attractors for the system dynamics in the presence of sufficiently strong driving by continuous injections of 10–300 keV electrons. Therefore, these analytical steady‐state solutions provide a simple means for estimating the most extreme electron energy spectra potentially encountered in the outer radiation belt, despite the great variability of injections and plasma conditions. These analytical steady‐state solutions are compared with numerical simulations based on the full Fokker‐Planck equation and with relativistic electron flux spectra measured by satellites during one extreme event and three strong events of high time‐integrated geomagnetic activity, demonstrating a good agreement. Key Points: Realistic analytical steady‐state electron energy spectra in the presence of wave‐driven energization and loss are providedSuch steady‐state solutions represent attractors for the system dynamics and correspond to the hardest electron energy spectraSteady‐state solutions are compared with numerical simulations and spacecraft observations, showing a good agreement [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
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