Daae M., Y. Y. Shprits, B. Ni, J. Koller, D. Kondrashov, Y. Chen, (2011), Reanalysis of radiation belt electron phase space density using various boundary conditions and loss models, Advances In Space Research, 48, 1327 – 1334, doi:10.1016/j.asr.2011.07.001

## Abstract

Data assimilation is becoming an increasingly important tool for understanding the near Earth hazardous radiation environments. Reanalysis of the radiation belts can be used to identify the electron acceleration mechanism and distinguish local acceleration from radial diffusion. However, for any practical applications we need to determine how reliable is reanalysis, and how significant is the dependence of the results on the assumptions of the code and choice of boundary conditions. We present the sensitivity of reanalysis of the radiation belt electron phase space density (PSD) to the assumed location of the outer boundary, using the VERB code and a Kalman filter. We analyze the sensitivity of reanalysis to changes in the electron-loss throughout the domain, and the sensitivity to the assumed boundary condition and its effect on the innovation vector. All the simulations presented in this study for all assumed loss models and boundary conditions, show that peaks in the phase space density of relativistic electrons build up between 4.5 and 6RE during relativistic electron flux enhancements in the outer radiation belt. This clearly shows that peaks build up in the heart of the electron radiation belt independent of the assumptions in the model, and that local acceleration is operating there. The work here is also an important step toward performing reanalysis using observations from current and future missions.## Authors (sorted by name)

Chen Daae Koller Kondrashov Ni Shprits## Journal / Conference

Advances In Space Research## Acknowledgments

We thank the WDC for Geomagnetism, Kyoto and GSFC/SPDF OMNIWeb for making geomagnetic indices easily accessible. This research was supported by the Lab Research Fee Grant 09-LR-04-200 116720-SHPY.## Grants

09‐LR‐04116720## Bibtex

@article{DAAE20111327,
title = "Reanalysis of radiation belt electron phase space density using various boundary conditions and loss models",
journal = "Advances in Space Research",
volume = "48",
number = "8",
pages = "1327 - 1334",
year = "2011",
issn = "0273-1177",
doi = "10.1016/j.asr.2011.07.001",
url = "http://www.sciencedirect.com/science/article/pii/S0273117711004741",
author = "M. Daae and Y.Y. Shprits and B. Ni and J. Koller and D. Kondrashov and Y. Chen",
keywords = "Data assimilation, Magnetosphere, Outer radiation belt",
abstract = "Data assimilation is becoming an increasingly important tool for understanding the near Earth hazardous radiation environments. Reanalysis of the radiation belts can be used to identify the electron acceleration mechanism and distinguish local acceleration from radial diffusion. However, for any practical applications we need to determine how reliable is reanalysis, and how significant is the dependence of the results on the assumptions of the code and choice of boundary conditions. We present the sensitivity of reanalysis of the radiation belt electron phase space density (PSD) to the assumed location of the outer boundary, using the VERB code and a Kalman filter. We analyze the sensitivity of reanalysis to changes in the electron-loss throughout the domain, and the sensitivity to the assumed boundary condition and its effect on the innovation vector. All the simulations presented in this study for all assumed loss models and boundary conditions, show that peaks in the phase space density of relativistic electrons build up between 4.5 and 6RE during relativistic electron flux enhancements in the outer radiation belt. This clearly shows that peaks build up in the heart of the electron radiation belt independent of the assumptions in the model, and that local acceleration is operating there. The work here is also an important step toward performing reanalysis using observations from current and future missions."
}