Introduction

The place of the Sun in the Universe and its role in life on the Earth are discussed. Despite the stability of the Sun as a star, it has a variable magnetic field, which is the source of solar activity. Some manifestations of the solar activity affect the Earth’s environment and cause disturbances in the terrestrial magnetic field, geomagnetic storms. Solar flares and coronal mass ejections are hazardous for satellites, space stations, and astronauts, especially if they work in outer space. Geomagnetic storms initiated by solar activity phenomena lead to numerous consequences in the terrestrial global technological infrastructure, mostly of a negative nature. Thus, space weather, which reflects the state of the electromagnetic environment in near-Earth space, is becoming of great importance for humanity.