VLF transmission induced slot electron precipitation

Analysis of electron observations in the drift and bounce loss cones of the slot region of the magnetosphere indicates that the predominant mode in which electrons in the 100 to 400 keV energy range arrive in the drift loss cone is via discrete events. These events are usually traceable back to the vicinity of a high-power-level VLF transmitter. No gradual buildup of electron flux, proceeding eastward from the South Atlantic Anomaly, is observed. Estimates of the loss rate due to the discrete events show that this process can result in a depletion of 50% per day of the electron flux in the slot region. The wave-particle interaction must occur relatively low on the field line (lambda approximately 30 deg to 50 deg) because of the relationship of particle energies and wave frequencies involved. Additional scattering of the particles near the equator, either by power-line harmonic emissions or naturally occurring ELF hiss, is required to transport the particles to the lower interaction region.