Bessel’s method in study of solar eclipse influence on the ionosphere
DOI:
https://doi.org/10.26565/2311-0872-2023-39-04Keywords:
ionosphere, solar eclipse, Bessel’s method, total electron content, TEC, eclipse phase, remote sensing, GPS, relative illuminanceAbstract
Relevance. A solar eclipse is a global disturbing factor that significantly changes the characteristics of the ionosphere. As is known, the ionosphere affects the propagation of radio waves of all ranges, that is, it affects the operation of navigation and radio astronomy systems, radars, telecommunications, and remote sensing of near-Earth space. Therefore, the study of the influence of solar eclipses on the ionosphere is an important task, which in general consists of astronomical and ionospheric parts of the work.
The purpose of this work is to present the elements of astronomical calculation methods developed for ionospheric research and to describe the results of using these methods to study the influence of solar eclipses on the ionosphere.
Methods and methodology. The methods are developed on the basis of the Bessel’s method, which makes it possible to significantly simplify calculations using the concept of the fundamental plane.
Results. Analytical relationships are obtained for the trace of the lunar shadow on the earth's surface, the eclipse phase, the magnitude of the obscuration, as well as the relative illuminance at the measurement point. Using the developed methods, GPS stations and satellite flights of the current constellation of satellites were optimally selected, the delay time of the main ionospheric response, which was approximately 30-40 minutes, and the relationship between the magnitude of the eclipse phase and the change in total electron content (TEC) were established. For eclipse phase 0.7, the TEC decrease was 3.5 TECU or 19%.
Conclusions. The developed methods make it possible to study the influence of solar eclipses on the ionosphere.
