A Test of Energetic Particle Precipitation Models Using Simultaneous
Incoherent Scatter Radar and Van Allen Probes Observations
Abstract
Quantification of energetic electron precipitation caused by
wave-particle interactions is fundamentally important to understand the
cycle of particle energization and loss of the radiation belts. One
important way to determine how well the wave-particle interaction models
predict losses through pitch-angle scattering into the atmospheric loss
cone is the direct comparison between the ionization altitude profiles
expected in the atmosphere due to the precipitating fluxes and the
ionization profiles actually measured with incoherent scatter radars.
This paper reports such a comparison using a forward propagation of
loss-cone electron fluxes, calculated with the electron pitch angle
diffusion model applied to Van Allen Probes measurements, coupled with
the Boulder Electron Radiation to Ionization (BERI) model, which
propagates the fluxes into the atmosphere. The density profiles measured
with the Poker Flat Incoherent Scatter Radar operating in modes
especially designed to optimize measurements in the D-region, show
multiple instances of quantitative agreement with predicted density
profiles from precipitation of electrons caused by wave-particle
interactions in the inner magnetosphere. There are two several-minute
long intervals of close prediction-observation approximation in the
65-93 km altitude range. These results indicate that the whistler
wave-electron interactions models are realistic and produce
precipitation fluxes of electrons with energies between 10 keV to
>100 keV that are consistent with observations.