The Effect of Compression Induced Chorus Waves on 10s to 100s eV
On 7 January 2014, a solar storm erupted, which eventually compressed
the Earth’s magnetosphere leading to the generation of chorus waves.
These waves enhanced local wave-particle interactions and led to the
precipitation of electrons from 10s eV to 100s keV. This paper shows
observations of a low energy cutoff in the precipitation spectrum from
Van Allen Probe B Helium Oxygen Proton Electron (HOPE) measurements.
This low energy cutoff is well replicated by the predicted loss
calculated from pitch angle diffusion coefficients from wave and plasma
observations on Probe B. To our knowledge, this is the first time a
single spacecraft has been used to demonstrate an accurate theoretical
prediction for chorus wave-induced precipitation and its low energy
cutoff. The specific properties of the precipitating soft electron
spectrum have implications for ionospheric activity, with the lowest
energies mainly contributing to thermospheric and ionospheric upwelling,
which influences satellite drag and ionospheric outflow.