Phase Cube Modeling of Ionospheric F-Layer Dipole Flute Instability Effects on High-Frequency Propagation

Flute instability is suspect to many of the ambiguities observed within the high-frequency (HF) spectrum during trans-ionospheric propagation. Applications such as over-the-horizon radar (OTHR) and geolocation satellites are susceptible to flute instability along the propagation path within the ionosphere’s F-layer region. The model developed in this research utilizes a unique phase cube geometry representation of a flute structure derived from two-fluid magnetohydrodynamics (MHDs). The phase cube provides a 3-D interface to a propagator coupled with ray tracing to account for the medium’s refractivity and intermediate field vector incident angles. The forward scattering calculations acquired from the model include a two-position two-frequency mutual coherence function (MCF), a scattering function, a power delay profile, a Doppler power spectrum, a frequency correlation function, and a spatial coherence function. Horizontal and vertical polarization effects are also examined with respect to the flute structure geometry. Delay-Doppler maps provide insights into the physical characteristics of scintillation arcs observed in the frequency-domain analysis of the dynamic spectrum. The results provide a baseline observation for spatial, temporal, and frequency characteristics observed after HF propagation through a flute channel. The results also indicate that the flute channel is likely to cause frequency-selective characteristics on the signal propagation along with significant spectral broadening in the Doppler power spectrum.