Lonolab-Ray: A Wave Propagation Algorithm for Anisotropic and Inhomogeneous Ionosphere

Abstract

A high-frequency (HF) radio wave propagation model based on ray tracing for anisotropic, inhomogeneous, and time-varying ionosphere is developed to form the basis for a user-friendly modular algorithm. The algorithm IONOLAB-RAY applies the principles of ray tracing through the spherical 3D grid model of the ionosphere. The physical parameters of the ionosphere in each voxel are obtained from the ionosphere model IRI-Plas-G. The refractive index of each voxel is calculated with the Appleton-Hartree formula, which includes electron cyclotron frequency, collision frequency, and anisotropicity due to the geomagnetic field. The developed propagation algorithm allows the input of total electron content (TEC) values to update the ionospheric model to the current conditions. This capability has an important impact on the characterization of the ionosphere under geomagnetic storm conditions. The algorithm can be further developed to represent typical HF transmitter and receiver antenna properties and to calculate the electric field strength, time delay, and polarization rotation at the receiver location.