Matrix-exponent formulations for wave radiation and propagation in anisotropic stratified ionosphere

A matrix-exponent method is developed to treat wave radiation and propagati on in anisotropic stratified ionosphere. By using matrix-exponent formulati ons, the present approach is relatively compact for expressions and reliabl e for computations. As an example, the method is used to calculate the ELF excitation of the earth-ionosphere waveguide by an equivalent dipole result ed from heating the lower ionosphere with modulated HF waves. Simulation re sults are presented and compared for different latitudes.