Interplay between the Amplitudes of VLF Transmitter Signals and High-Energy Electron Precipitation during Geomagnetic Disturbances

The authors discuss an anomalous drop in the amplitude of the magnetic field components of signals from the VLF transmitter at the Lovozero (LOZ) research station during geomagnetic disturbances at night to daytime values. Auroral precipitation is observed at station LOZ during this period, and riometer absorption is detected at the Sodankylä and Ivalo observatories. According to data from the POES satellite, precipitation of electrons with energies of >612 keV is observed in the area of station LOZ. The scale of the projection of the area of precipitation for particles with energies >287 keV is ∼200 km on average. Numerical modeling shows the experimentally observed effect of a nighttime drop in the amplitudes of the VLF transmitter’s signal can be explained by an inhomogeneity in the ionosphere caused by a flux of electrons with energies >200 keV and inhomogeneity scales of ∼200 km.