Altitude profiles of localized D region density disturbances produced in lightning-induced electron precipitation events


  • Sean J. Lev-Tov,

  • Umran S. Inan,

  • Timothy F. Bell


A three-dimensional model of very low frequency (VLF) radio wave propagation in the Earth-ionosphere waveguide in the presence of lower ionospheric disturbances is used to quantitatively interpret VLF signatures of lightning-induced electron precipitation (LEP) events observed in two previously reported cases. One case is that of a 28.5-kHz signal originating in Puerto Rico and propagating to a receiver in Lake Mistissini, Quebec. The other case involves a 24.0-kHz signal originating in Cutler, Maine, and received at Stanford, California. In both cases, high-resolution measurements of the VLF signals were made to accurately document characteristic signatures of LEP events (Inan et al., 1988b, 1990). The comparison of the model calculations with the data yields information about the altitude profiles of electron density of both the extra ionization produced by the LEP events and of the ambient ionospheric D region. The comparisons are carried out using generally accepted values of the spatial extent of the disturbed regions and the intensity of the particle flux constituting the LEP burst.