Mode theory of whistler ducts: integrated group delay times

摘要: Abstract Field-aligned enhancements of plasma density act as waveguides for whistler-mode waves. Calculations are presented mode characteristics a planar structure, where the enhancement has sech-squared profile. Particular attention is paid to group velocity different waveguide modes. Application then made magnetosphere by calculating delay per unit length given at latitudes along duct (taken be centred on dipole field line) and integrating obtain total over magnetospheric part whistler path. Compared with strictly longitudinal propagation, travel times less low frequencies, but greater frequencies near one-half equatorial electron gyrofrequency, magnitude residuals extremes frequency range being higher-order Differences between modes can order milliseconds. It therefore seems possible that recently reported fine structure seen in spectrograms could due multi-mode propagation.