Dependence of radiation belt simulations to assumed radial diffusion rates tested for two empirical models of radial transport
Author  
Keywords  
Abstract 
Radial diffusion is one of the dominant physical mechanisms that drives acceleration and loss of the radiation belt electrons, which makes it very important for nowcasting and forecasting space weather models. We investigate the sensitivity of the two parameterizations of the radial diffusion of Brautigam and Albert (2000) and Ozeke et al. (2014) on longterm radiation belt modeling using the Versatile Electron Radiation Belt (VERB). Following Brautigam and Albert (2000) and Ozeke et al. (2014), we first perform 1D radial diffusion simulations. Comparison of the simulation results with observations shows that the difference between simulations with either radial diffusion parameterization is small. To take into account effects of local acceleration and loss, we perform 3D simulations, including pitch angle, energy, and mixed diffusion. We found that the results of 3D simulations are even less sensitive to the choice of parameterization of radial diffusion rates than the results of 1D simulations at various energies (from 0.59 to 1.80 MeV). This result demonstrates that the inclusion of local acceleration and pitch angle diffusion can provide a negative feedback effect, such that the result is largely indistinguishable simulations conducted with different radial diffusion parameterizations. We also perform a number of sensitivity tests by multiplying radial diffusion rates by constant factors and show that such an approach leads to unrealistic predictions of radiation belt dynamics.

Year of Publication 
2017

Journal 
Space Weather

Volume 
15

Number of Pages 
150162

Date Published 
01/2017

URL 
http://onlinelibrary.wiley.com/doi/10.1002/2016SW001426/full

DOI 
10.1002/swe.v15.110.1002/2016SW001426
