title: Analytic expressions for ULF wave radiation belt radial diffusion coefficients.
abstract: We present analytic expressions for ULF wave-derived radiation belt radial diffusion coefficients, as a function ofLandKp, which can easily be incorporated into global radiation belt transport models. The diffusion coefficients are derived from statistical representations of ULF wave power, electric field power mapped from ground magnetometer data, and compressional magnetic field power from in situ measurements. We show that the overall electric and magnetic diffusion coefficients are to a good approximation both independent of energy. We present example 1-D radial diffusion results from simulations driven by CRRES-observed time-dependent energy spectra at the outer boundary, under the action of radial diffusion driven by the new ULF wave radial diffusion coefficients and with empirical chorus wave loss terms (as a function of energy,KpandL). There is excellent agreement between the differential flux produced by the 1-D,Kp-driven, radial diffusion model and CRRES observations of differential electron flux at 0.976 MeV-even though the model does not include the effects of local internal acceleration sources. Our results highlight not only the importance of correct specification of radial diffusion coefficients for developing accurate models but also show significant promise for belt specification based on relatively simple models driven by solar wind parameters such as solar wind speed or geomagnetic indices such asKp.
  
  
  CONCLUSIONS
  Analytic expressions for the radial diffusion coefficients are presentedThe coefficients do not dependent on energy or wavemvalueThe electric field diffusion coefficient dominates over the magnetic.
authors.affiliation: Department of Physics, University of Alberta Edmonton, Alberta, Canada.
authors.forename: Louis G
authors.initials: LG
authors.lastname: Ozeke
authors.affiliation: Department of Physics, University of Alberta Edmonton, Alberta, Canada.
authors.forename: Ian R
authors.initials: IR
authors.lastname: Mann
authors.affiliation: Department of Physics, University of Alberta Edmonton, Alberta, Canada.
authors.forename: Kyle R
authors.initials: KR
authors.lastname: Murphy
authors.affiliation: Department of Physics, University of Alberta Edmonton, Alberta, Canada ; Mullard Space Science Laboratory Dorking, UK.
authors.forename: I
authors.initials: I
authors.lastname: Jonathan Rae
authors.affiliation: Department of Physics, University of Alberta Edmonton, Alberta, Canada.
authors.forename: David K
authors.initials: DK
authors.lastname: Milling