AE012-0007
Analysis of LEP events and their impact on radiation belt dynamics
Analysis of LEP events and their impact on radiation belt dynamics
Friday, 11 December 2020
Poster
Abstract:
The dynamics of the Earth's radiation belts are shaped by a multitude of factors whose precise contributions remain a subject of mystery and research. 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).
We have worked to build a database of these events. Our detection process begins with using the National Lightning Detection Network (NLDN) as a starting point for candidate lightning strokes. We use Georgia Tech's network of AWESOME receivers across the continental US to observe VLF waveforms that propagate near candidate strokes. Using a neural network classifier, we are able to analyze these waveforms and detect LEP events. This has allowed us to assemble 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. The difference appears to be a function of L-Shell and longitude.This indicates that whistler waves from terrestrial lightning may play a significant role in the radiation belt electron distribution, but further research and modeling is required to quantify this role.
We have worked to build a database of these events. Our detection process begins with using the National Lightning Detection Network (NLDN) as a starting point for candidate lightning strokes. We use Georgia Tech's network of AWESOME receivers across the continental US to observe VLF waveforms that propagate near candidate strokes. Using a neural network classifier, we are able to analyze these waveforms and detect LEP events. This has allowed us to assemble 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. The difference appears to be a function of L-Shell and longitude.This indicates that whistler waves from terrestrial lightning may play a significant role in the radiation belt electron distribution, but further research and modeling is required to quantify this role.