Optical signatures of lightning-induced electron precipitation

Abstract

Model calculations are conducted to estimate the optical emission brightness caused by lightning-induced electron precipitation. Pitch angle scattering of energetic radiation belt electrons by lightning-generated whistler mode waves results in precipitation in the upper atmosphere. Assuming a lightning peak current and location, plasmasphere distribution, and radiation belt density and pitch angle distributions, we calculate the secondary ionization production and optical emissions in a number of lines and bands. We find that the brightness in N2 1P and O(1S) may reach a few to 10 R for a 100 kA peak current discharge, with a distinct spatial and temporal signature of 1-2 s. A simple signal-to-noise ratio (SNR) calculation shows that this signature should be detectable with modern photometric instruments with an SNR ∼4. We further investigate the dependence of this brightness on lightning source latitude and peak current. Copyright 2011 by the American Geophysical Union.