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Is Kp the Best Magnetic Activity Parameterization for Radial Diffusion Models in the Outer Radiation Belt?
  • Fira Fatmasiefa,
  • Solène Lejosne
Fira Fatmasiefa
Space Sciences Laboratory, UC Berkeley

Corresponding Author:firafsiefa_@berkeley.edu

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Solène Lejosne
University of California, Berkeley
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Specifying radial diffusion magnitude is one of the main requirements for physics-based radiation belt models. Yet, radial diffusion quantification remains uncertain. The most commonly used parameterization for the logarithm of radial diffusion magnitude is a linear function of a magnetic index, Kp, with a coarse time resolution of three hours. This work presents alternate linear parameterizations of similar quality for the logarithm of radial diffusion magnitude, considering other magnetic indices and solar wind parameters. Using a time series for the logarithm of electromagnetic radial diffusion magnitude with a 1-minute time resolution, we investigate linear relationships with magnetic indices such as Kp, Hp60, Hp30, AE, SymH, and Dst and solar wind parameters such as solar wind dynamic pressure, solar wind speed and the north‐south component of the interplanetary magnetic field. We find that Kp, Hp60, Hp30, and solar dynamical pressure yield the strongest linear correlation with the logarithm of radial diffusion magnitude. We also provide simple, linear models of the logarithm of radial diffusion magnitude that best fit the time series. This work contributes to improving the time resolution for radial diffusion parameterization and radiation belt models. In particular, it suggests that Hp60 and Hp30 could also be used in place of Kp in the most commonly used Kp‐driven parameterization for radiation belt radial diffusion.