The proposed effort during 1995-1996 is to 1) study the locations and size distribution of magnetospheric ducts, 2) greatly improve current estimates of loss rates of radiation belt electrons due to VLF waves from lightning, chorus, and other coherent waves, 3) clarify the relative roles of ducted and non-ducted whistler mode waves in the diffusion and precipitation of radiation belt particles, and 4) study the mechanisms responsible for high latitude precipitation bursts. This study will be based on precipitating electron records acquired in 1982 by the SEEP (Stimulated Emission of Energetic Particles) satellite and by VLF wave receivers on the ground and on satellites. Electron precipitation by ducted whistlers and by other VLF waves is thought to be the major loss mechanism for radiation belt electrons. However, the relative importance of ducted whistlers, unducted whistlers, chorus, and hiss is controversial. The SEEP satellite with its low altitude orbit, large geometric factor detectors, and high data collection rates has acquired an unique data set which can be used to address these issues. In addition, VLF wave data from ground stations and satellites were obtained during the time interval SEEP was operating and will be used to associate wave characteristics with the particle precipitation. This work will improve knowledge of magnetospheric duct dimensions, will provide quantitative information on the fine structure of lightning-induced electron precipitation and on the number of electrons precipited by ducted whistlers, should give information on the precipitation rates caused by non-ducted whistlers and other VLF emissions. Analysis of the high resolution electron data should also constrain the possible mechanisms responsible of the high latitude electron precipitation bursts.
