TID Characteristics Obtained by Modeling HF Radio Wave Propagation Along Slightly Oblique Paths At Mid-Latitudes

We present the results of modeling of synchronous propagation of decameter radio waves along three slightly oblique paths in the mid-latitude ionosphere when a sickle-shaped traveling ionospheric disturbance (TID) is recorded. The ray tracing of waves propagating in a smoothly inhomogeneous ionospheric magnetoplasma is performed. Distance–frequency characteristics of oblique chirp sounding of the ionosphere, obtained on December 19, 2019 with an interval of 1 min on the Vasilsursk–Nizhny Novgorod, Yoshkar-Ola–Nizhny Novgorod, and Yoshkar-Ola–Vasilsursk paths, are used as initial data. The perturbation of the electron number density profile during the TID passage is modeled by a harmonic function (localized plane half-wave), and its parameters are selected according to the best agreement between the simulation results and the experimental data. Estimates of the TID propagation azimuth and velocity in this direction were 105° and 65–105 m/s, respectively.