Home » Cervantes Villa et al. 2020

Quantifying the Effects of EMIC Wave Scattering and Magnetopause Shadowing in the Outer Electron Radiation Belt by Means of Data Assimilation

Cervantes Villa S., Y. Y. Shprits, N. A. Aseev, H. J. Allison, (2020), Quantifying the Effects of EMIC Wave Scattering and Magnetopause Shadowing in the Outer Electron Radiation Belt by Means of Data Assimilation, J. of Geophys. Res. [Space Physics], 125, e2020JA028208, doi:10.1029/2020JA028208, e2020JA028208 10.1029/2020JA028208

Abstract

Abstract In this study we investigate two distinct loss mechanisms responsible for the rapid dropouts of radiation belt electrons by assimilating data from Van Allen Probes A and B and Geostationary Operational Environmental Satellites (GOES) 13 and 15 into a 3-D diffusion model. In particular, we examine the respective contribution of electromagnetic ion cyclotron (EMIC) wave scattering and magnetopause shadowing for values of the first adiabatic invariant μ ranging from 300 to 3,000 MeV G−1. We inspect the innovation vector and perform a statistical analysis to quantitatively assess the effect of both processes as a function of various geomagnetic indices, solar wind parameters, and radial distance from the Earth. Our results are in agreement with previous studies that demonstrated the energy dependence of these two mechanisms. We show that EMIC wave scattering tends to dominate loss at lower L shells, and it may amount to between 10%/hr and 30%/hr of the maximum value of phase space density (PSD) over all L shells for fixed first and second adiabatic invariants. On the other hand, magnetopause shadowing is found to deplete electrons across all energies, mostly at higher L shells, resulting in loss from 50%/hr to 70%/hr of the maximum PSD. Nevertheless, during times of enhanced geomagnetic activity, both processes can operate beyond such location and encompass the entire outer radiation belt.

Authors (sorted by name)

Allison Aseev Cervantes Villa Shprits

Journal / Conference

Journal Of Geophysical Research (Space Physics)

Bibtex

@article{https://doi.org/10.1029/2020JA028208,
author = {Cervantes Villa, S. and Shprits, Y. Y. and Aseev, N. A. and Allison, H. J.},
title = {Quantifying the Effects of EMIC Wave Scattering and Magnetopause Shadowing in the Outer Electron Radiation Belt by Means of Data Assimilation},
journal = {Journal of Geophysical Research: Space Physics},
volume = {125},
number = {8},
pages = {e2020JA028208},
keywords = {data assimilation, EMIC waves, magnetopause shadowing, innovation vector, Kalman filter, radiation belt losses},
doi = {https://doi.org/10.1029/2020JA028208},
url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2020JA028208},
eprint = {https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2020JA028208},
note = {e2020JA028208 10.1029/2020JA028208},
abstract = {Abstract In this study we investigate two distinct loss mechanisms responsible for the rapid dropouts of radiation belt electrons by assimilating data from Van Allen Probes A and B and Geostationary Operational Environmental Satellites (GOES) 13 and 15 into a 3-D diffusion model. In particular, we examine the respective contribution of electromagnetic ion cyclotron (EMIC) wave scattering and magnetopause shadowing for values of the first adiabatic invariant μ ranging from 300 to 3,000 MeV G−1. We inspect the innovation vector and perform a statistical analysis to quantitatively assess the effect of both processes as a function of various geomagnetic indices, solar wind parameters, and radial distance from the Earth. Our results are in agreement with previous studies that demonstrated the energy dependence of these two mechanisms. We show that EMIC wave scattering tends to dominate loss at lower L shells, and it may amount to between 10%/hr and 30%/hr of the maximum value of phase space density (PSD) over all L shells for fixed first and second adiabatic invariants. On the other hand, magnetopause shadowing is found to deplete electrons across all energies, mostly at higher L shells, resulting in loss from 50%/hr to 70%/hr of the maximum PSD. Nevertheless, during times of enhanced geomagnetic activity, both processes can operate beyond such location and encompass the entire outer radiation belt.},
year = {2020}
}