Arbitrary propagation of HM waves along theFregion

Longitudinal and transverse propagation along an idealized three-region waveguide is examined prior to setting up a more general numerical solution that may account for arbitrary ionosphere parameters. For a nighttime ionosphere model, propagation in the east-to-west direction exhibits higher attenuation rates α than the propagation in the west-to-east direction, but α remains below 7 db/1000 km for dip angles I > 75° and I < 50°. The phase velocity may exceed 2000 km/sec for the smaller values of I. For propagation between the east-to-west and north-to-south directions, modes of low attenuation rates are possible for large and small values of I, and again small values of I are associated with large phase velocities; however, there is also the possibility of highly attenuated modes for small dip angles I.