Events in Physics

During a solar flare, enhanced fluxes in various spectral lines and continua lead to increased ionisation in the sunlit portion of Earth’s ionosphere, resulting in variations of electron density across different ionospheric altitudes. These changes affect the propagation, reflection, and absorption of radio waves over a broad range of frequencies. While the dynamics of ionospheric total electron content (TEC) driven by the impulsive phase of solar flares are relatively well understood, important questions remain regarding the altitude-dependent redistribution of electron density induced by flares with different spectral characteristics. As for the late phase of solar flares, its impact on the ionosphere was first detected and quantitatively assessed only in 2024. This talk presents the first multi-event study of ionospheric responses to different phases of X-class solar flares with various locations on the solar disk.