Effects of Geomagnetic Field Models on Whistler-mode Ray Tracing at Low Latitude

In view of the large difference between the real geomagnetic field and the dipolar model field at low latitudes, ray tracing for whistler-mode wave propagation has been performed with IGRF (n=6). It is found that there are two narrow nonducted propagation outlets of whistler-mode wave at about 9° Nand 12°N, their starting regions are in the area of storm activity. The cutoff latitude of outlet of whistler-mode wave is at 8°N-9°N. The results of this computation can be used satisfactorily to explain the fact that the dispersion of whistler at low latitude is in positive correlation with f₀/F₂.