HF prediction using adiabatic invariant theory

Gurevich and Tsedilina's adiabatic invariant theory for the potential well model of ionospheric HF radiowave propagation is reviewed and applied to a specific round-the-world (RTW) propagation path. Propagation modes (ducting, ground-hop and chordal) are qualitatively deduced from charts of the adiabatic invariants I(F), I(FE), I(FE+E) and I(1) vs path length. Quantitative results are presented in the form of a simulated RTW ionogram between an elevated source and receiver. In support of RADC's orbiting receiver experiment, the robustness of global HF propagation is displayed in the form of synoptic maps of I(E), I(F), I(FE) and I(1), using the IONCAP medium model ionosphere. These maps show the abundance of various propagation modes on a world-wide basis.