Quantifying the radiation belt response to lightning via ground-based VLF and Van Allen Probe data

Many factors contribute to the loss mechanisms of electrons in the Earth's radiation belts, but the relative significance of these causes remains a subject of mystery and debate. One such component is lightning-produced whistler-wave radiation. These electromagnetic waves, which take on a unique “whistler” dispersion profile under the plasma conditions of the magnetosphere, dislodge trapped electrons in the radiation belts and cause precipitation in the D region of the ionosphere. We are able to detect these Lightning-induced Electron Precipitation (LEP) events using Very Low Frequency (VLF remote sensing). In our work, we assembled a large database of 7720 LEP events from November 2017 to August 2019. We separated the days in January-June 2019 into “High LEP” and “Low LEP” days. Using data from the Van Allen Probes over this period, we found a significant difference in the observed electron flux between these two datasets. This indicates that whistler waves from terrestrial lightning play a significant role in the radiation belt electron distribution, but further research and modeling is required to quantify this role.