Active and Passive Applications of VLF Waves

The projects hopes to address two topics: 1. The impact of Terrestrial Gamma-ray Flashes (TGFs) on the ionosphere. This will be undertaken using narrowband VLF data which provides continuous monitoring of the lower ionosphere. A number of VLF transmitte r-receiver paths traverse the equator, which is the principal location of TGFs, so it is quite likely that TGF signatures will be discernible in the VLF data. However, the signatures are likely to be weak, so we will expand an existing method for enhancin g the signal-to-noise ratio in this data. 2. Lighting as a driver of electron precipitation from the radiation belts. Data from the World Wide Lightning Location Network (WWLLN) and satellite lightning detection systems will be used to construct a model of the energy input from global lightning into the magnetosphere as a function of magnetic latitude and magnetic local time. This model will then be used to estimate the effect that lightning has on depleting the flux of energetic particles in the radiati on belts. The resulting estimate of precipitation flux will be compared with in situ measurements from low earth orbiting satellites.