THE INFLUENCE OF IONOSPHERIC ION ABUNDANCES ON THE LONGITUDINAL EFFECT OF WHISTLER PROPAGATION AT LOW LATITUDE

The observation results of Iss-b satellite show that ionospheric ion abundances vary with longitudes. The most realistic ionospheric electron density models are selected to trace whistler rays of low latitudes in 130°Eand 114°Emeridian planes. The computational results show that the longitudinal variations of vertical gradients of electron density controlled by [O⁺] , [He⁺] and [H⁺] result in the longitudinal effect of whistler propagation. Low latitude whistlers in 130°Esatisfy the penetrating condition |μsinδ |≤1 better than that in 114°E. It is found that the influence of longitudinal variation of vertical gradients of electron density controlled by ion abundances is greater than that of horizontal gradients of electron density controlled by equatorial anomaly. The observed whistler occurrence rates at Wuchang (30.5°N Geog., 114.6°E; 19.3°N Geom) and Kagoshima (31.5°N, 130.8°E; 20.5°N) are in good agreement with the theoretical predictions in this paper.