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EMIC wave parameterization in the long-term VERB code simulation

Drozdov A. Y., Y. Y. Shprits, M. E. Usanova, N. A. Aseev, A. C. Kellerman, H. Zhu, (2017), EMIC wave parameterization in the long-term VERB code simulation, J. of Geophys. Res. [Space Physics], 122, 8488-8501, doi:10.1002/2017JA024389

Abstract

Abstract Electromagnetic ion cyclotron (EMIC) waves play an important role in the dynamics of ultrarelativistic electron population in the radiation belts. However, as EMIC waves are very sporadic, developing a parameterization of such wave properties is a challenging task. Currently, there are no dynamic, activity-dependent models of EMIC waves that can be used in the long-term (several months) simulations, which makes the quantitative modeling of the radiation belt dynamics incomplete. In this study, we investigate Kp, Dst, and AE indices, solar wind speed, and dynamic pressure as possible parameters of EMIC wave presence. The EMIC waves are included in the long-term simulations (1 year, including different geomagnetic activity) performed with the Versatile Electron Radiation Belt code, and we compare results of the simulation with the Van Allen Probes observations. The comparison shows that modeling with EMIC waves, parameterized by solar wind dynamic pressure, provides a better agreement with the observations among considered parameterizations. The simulation with EMIC waves improves the dynamics of ultrarelativistic fluxes and reproduces the formation of the local minimum in the phase space density profiles.

Authors (sorted by name)

Aseev Drozdov Kellerman Shprits Usanova Zhu

Journal / Conference

Journal Of Geophysical Research (Space Physics)

Acknowledgments

The authors used geomagnetic indices provided by OMNIWeb (http://omniweb.gsfc.nasa.gov/form/dx1.html) and are grateful to the RBSP‐ECT team for the provision of the Van Allen Probes observations (http://www.rbsp‐ect.lanl.gov/). The diffusion coefficients used in the VERB code are available on the Space Environment Modeling Group website (ftp://rbm.epss.ucla.edu/). The authors would like to acknowledge high‐performance computing support from Yellowstone (ark:/85065/d7wd3xhc) provided by UCAR's Computational and Information System Laboratory, sponsored by the National Science Foundation and other agencies and computational and storage services associated with the Hoffman2 Shared Cluster provided by UCLA Institute for Digital Research and Education's Research Technology Group. This research was supported by the NASA grant NNX16AF91G and by European Union's Horizon 2020 research and innovation program under grant agreement 637302.

Grants

637302 NNX16AF91G

Bibtex

@article{doi:10.1002/2017JA024389,
author = {Drozdov, A. Y. and Shprits, Y. Y. and Usanova, M. E. and Aseev, N. A. and Kellerman, A. C. and Zhu, H.},
title = {EMIC wave parameterization in the long-term VERB code simulation},
journal = {Journal of Geophysical Research: Space Physics},
volume = {122},
year = {2017},
number = {8},
pages = {8488-8501},
keywords = {radiation belts, VERB code, EMIC},
doi = {10.1002/2017JA024389},
url = {https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1002/2017JA024389},
eprint = {https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1002/2017JA024389},
abstract = {Abstract Electromagnetic ion cyclotron (EMIC) waves play an important role in the dynamics of ultrarelativistic electron population in the radiation belts. However, as EMIC waves are very sporadic, developing a parameterization of such wave properties is a challenging task. Currently, there are no dynamic, activity-dependent models of EMIC waves that can be used in the long-term (several months) simulations, which makes the quantitative modeling of the radiation belt dynamics incomplete. In this study, we investigate Kp, Dst, and AE indices, solar wind speed, and dynamic pressure as possible parameters of EMIC wave presence. The EMIC waves are included in the long-term simulations (1 year, including different geomagnetic activity) performed with the Versatile Electron Radiation Belt code, and we compare results of the simulation with the Van Allen Probes observations. The comparison shows that modeling with EMIC waves, parameterized by solar wind dynamic pressure, provides a better agreement with the observations among considered parameterizations. The simulation with EMIC waves improves the dynamics of ultrarelativistic fluxes and reproduces the formation of the local minimum in the phase space density profiles.}
}