Ducted and unducted propagation of VLF transmitter signals

Abstract:

Signals of powerful ground transmitters at various places have been detected by satellites in near-Earth space. The study on propagation mode, ducted or nonducted, has attracted much attentions for several decades. The propagation characteristics of VLF transmitter signals in the magnetosphere are critical for quantitatively assessing their contribution to energetic electron loss in radiation belts. Statistical wave power distribution based on combined Van Allen Probes and DEMETER satellite data reveals observed propagation routes in the meridian plane in the magnetosphere for each of various powerful transmitters. The propagation routes are consistent with nonducted ray tracing propagation mode. Combining the observed wave power distribution of VLF transmitter signals and ray tracing simulation, electron scattering coefficients are derived and the electron lifetime is estimated Discussion will be made on comparison with the results due to ducted propagation.