?
Whistler Growth Rates in the Magnetosphere According to Measurements of Energetic Electron Fluxes on the Van Allen Probe A Satellite
Measurements of the differential fluxes of energetic electrons in the equatorial region of the magnetosphere
in the energy range from units of keV to hundreds of keV carried out on Van Allen Probes make it
possible to obtain the distribution function of electrons resonantly interacting with whistlers in the VLF range
and to calculate the corresponding local growth rates (or increments) of the waves. The article presents the
results of the reconstruction of the distribution function of energetic electrons, as well as the direct calculation
of the wave increments without any model assumptions about the form of the distribution function. The data
from the Van Allen Probe A satellite on electron fluxes in the energy range of 33–143 keV are used, and the
dependence of the increment on frequency along the satellite path is calculated. The obtained increment values
are compared with the spatial and temporal variations in VLF emissions detected by the satellite. An
important feature of the calculated increments is their significant variation during the time between successive
measurements of the fluxes, i.e., at times on the order of 11 s.