A Comparison of Radial Diffusion Coefficients in 1-D and 3-D Long-Term Radiation Belt Simulations

Radial diffusion is one of the dominant physical mechanisms that drives acceleration andloss of the radiation belt electrons due to wave-particle interactions with ultra-low frequency (ULF) waves, which makes it very important for radiation belt modeling and forecasting.  We investigate the sensitivity of several parameterizations of the radial diffusion including Brautigam and Albert (2000), Ozeke et al. (2014), Ali et al. (2016), and Liu et al. (2016) on long-term radiation belt modeling using the Versatile Electron Radiation Belt (VERB) code.  Following previous studies, we first perform 1-D radial diffusion simulations.  To take into account effects of local acceleration and loss, we perform additional 3-D simulations, including pitch-angle, energy and mixed diffusion.