@seminar{Drozdov2024-n1,
  author       = {Drozdov, A. Y.},
  title        = {Modeling and Observations of Radiation Belt Dynamics: From Seed to Multi-MeV Electrons},
  year         = {2024},
  series       = {Special Heliophysics Division Seminar},
  organization = {NASA GSFC},
  month        = {Exact month. If present, it appears at month, year},
  address      = {Greenbelt, MD, USA},
  note         = {Building 21},
  abstract     = {This seminar will explore the dynamics of the radiation belt using numerical modeling and observations from NASA Van Allen Probes and other satellite missions. Central to the discussion is the Versatile Electron Radiation Belt (VERB) code, a powerful tool based on the Fokker-Planck equation. The results of the modeling revealed that the dynamics of the multi-MeV electrons differ significantly from those at ~MeV energies. Importantly, the electromagnetic ion cyclotron (EMIC) waves play a particular role in scattering multi-MeV electrons and contributing to their loss. This was confirmed via measurements and various modeling efforts, which led to the development of EMIC wave parameterization, and exploration of the role of hiss and chorus waves in the overall radiation belt dynamics. Acting as a fast, localized loss mechanism, EMIC waves lead to the formation of narrowed pitch-angle distributions and local minima in phase space density (PSD) profiles, which was confirmed statistically by observations. Interestingly, the local PSD minima were also discovered in the energy range of 'seed' electrons (~1 - 100s keV). Recent results suggest that there is a missing loss mechanism that drives additional precipitation of low-energy electrons. Overall, the VERB code and numerical modeling have proven to be powerful tools that, when used in conjunction with data assimilation and machine learning, can significantly enhance our understanding of radiation belts and prediction of space weather dynamics.}
}