Effects of the May 10–13, 2024 extreme magnetic storm in the Asian region of Russia have been studied using experimental data from vertical and oblique sounding of the ionosphere with a continuous chirp signal. Features of ionospheric disturbances induced by the magnetic storm have been revealed: the long-lasting negative ionospheric disturbance that was manifested as a significant decrease in F2-layer critical frequencies and maximum observed frequencies of radio paths; the absence of HF signal reflections from F-region due to sporadic Es layer and increased absorption of HF signals; recording of auroral and oblique Es layers; the long-lasting G-effect during local daytime during which the F1-layer critical frequency exceeded the F2-layer critical frequency; the dusk enhancement of electron density and F2-layer peak height. We have found a correlation of variations in ionospheric parameters and the maximum observed frequencies of HF radio wave propagation modes with spatial location of the main ionospheric trough and the equatorial boundary of the diffuse electron precipitation zone.
Ponomarchuk et al. (Wed,) studied this question.