Shprits Y. Y., A. C. Kellerman, A. Y. Drozdov, H. E. Spence, G. D. Reeves, D. N. Baker, (2015), Combined convective and diffusive simulations: VERB-4D comparison with 17 March 2013 Van Allen Probes observations, Geophysical Research Letters, 42, 9600-9608, doi:10.1002/2015GL065230

Abstract

Abstract This study is focused on understanding the coupling between different electron populations in the inner magnetosphere and the various physical processes that determine evolution of electron fluxes at different energies. Observations during the 17 March 2013 storm and simulations with a newly developed Versatile Electron Radiation Belt-4D (VERB-4D) are presented. Analysis of the drift trajectories of the energetic and relativistic electrons shows that electron trajectories at transitional energies with a first invariant on the scale of ~100 MeV/G may resemble ring current or relativistic electron trajectories depending on the level of geomagnetic activity. Simulations with the VERB-4D code including convection, radial diffusion, and energy diffusion are presented. Sensitivity simulations including various physical processes show how different acceleration mechanisms contribute to the energization of energetic electrons at transitional energies. In particular, the range of energies where inward transport is strongly influenced by both convection and radial diffusion are studied. The results of the 4-D simulations are compared to Van Allen Probes observations at a range of energies including source, seed, and core populations of the energetic and relativistic electrons in the inner magnetosphere.

Authors (sorted by name)

Baker Drozdov Kellerman Reeves Shprits Spence

Journal / Conference

Geophysical Research Letters

Acknowledgments

We would like to thank UCLA programmer Dmitri Subbotin for his contributions to the development of the VERB code. We would like to thank UCLA undergraduate students Josh Adler and Alec Jen who worked on testing, validating, and documenting the code. We would also like to thank Michael Schulz, Richard Thorne, Paul O'Brien, and Mary Hudson for useful discussion. This research was supported by NASA awards NNX10AK99G and NNX13AE34G, NSF award AGS‐1243183, UC Lab Fee award 116720, and Horizon 2020 award 637302. We would like to thank ECT and EMFISIS Van Allen Probes teams for providing data which is publically available at the JHU/APL website.

Grants

116720 637302 AGS‐1243183 NNX10AK99G NNX13AE34G

Bibtex

@article{doi:10.1002/2015GL065230,
author = {Shprits, Yuri Y. and Kellerman, Adam C. and Drozdov, Alexander Y. and Spence, Harlan E. and Reeves, Geoffrey D. and Baker, Daniel N.},
title = {Combined convective and diffusive simulations: VERB-4D comparison with 17 March 2013 Van Allen Probes observations},
year={2015},
journal = {Geophysical Research Letters},
volume = {42},
number = {22},
pages = {9600-9608},
keywords = {radiation belts, inner magnetosphere, Van Allen Probes, ring current, numerical simulations, wave-particle interactions},
doi = {10.1002/2015GL065230},
url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1002/2015GL065230},
eprint = {https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1002/2015GL065230},
abstract = {Abstract This study is focused on understanding the coupling between different electron populations in the inner magnetosphere and the various physical processes that determine evolution of electron fluxes at different energies. Observations during the 17 March 2013 storm and simulations with a newly developed Versatile Electron Radiation Belt-4D (VERB-4D) are presented. Analysis of the drift trajectories of the energetic and relativistic electrons shows that electron trajectories at transitional energies with a first invariant on the scale of ~100 MeV/G may resemble ring current or relativistic electron trajectories depending on the level of geomagnetic activity. Simulations with the VERB-4D code including convection, radial diffusion, and energy diffusion are presented. Sensitivity simulations including various physical processes show how different acceleration mechanisms contribute to the energization of energetic electrons at transitional energies. In particular, the range of energies where inward transport is strongly influenced by both convection and radial diffusion are studied. The results of the 4-D simulations are compared to Van Allen Probes observations at a range of energies including source, seed, and core populations of the energetic and relativistic electrons in the inner magnetosphere.}
}