This project measures perturbations to subionospheric very low frequency (VLF) radio signals caused by the precipitation of energetic magnetospheric electrons. The trapped electrons are scattered into the atmospheric loss cone by whistler waves produced by atmospheric lightning discharges. The sudden heating and ionization of the lower ionosphere causes changes in the amplitude and phase of the VLF signal. The measurement supported by this grant are made at Palmer Station, Antarctica, and they complement similar measurement made at three northern hemisphere sites by the same investigators, but supported by another NSF program. By observing several VLF transmitters from several sites it is possible to "image" the ionospheric disturbances.
