Mass ejections from the solar atmosphere
Pushkov Institute of Terrestrial Magnetism, Ionosphere and Radio Wave Propagation, Russian Academy of Sciences, Kaluzhskoe shosse 4, Troitsk, Москва, 108840, Russian Federation
Coronal mass ejections are the largest-scale eruptive phenomenon in the solar system. Their drastic effect on space weather is a reason for the significant interest to observe, simulate, and forecast these events. We describe the main features of mass ejections from the solar atmosphere, their physical parameters, and frequency of the event and its dependence on the solar cycle phase. We consider potential sources of ejections in the solar atmosphere and the magnetic field configurations wherein the energy needed for sudden explosive acceleration of large masses of matter can be stored. Main instabilities of coronal structures that lead to triggering and development of the eruptive processes are analyzed. We show that the coronal mass ejections are related to other manifestations of solar activity, while the eruptive processes observed using various techniques in various solar-atmosphere layers and interplanetary space are the same phenomenon. We discuss the indicators of the Sun's pre-eruptive regions approaching catastrophe and the options to use them to forecast eruptions and space weather disturbances.