Mass ejections from the solar atmosphere

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 in observing, simulating, and forecasting these events. We describe the main features of mass ejections from the solar atmosphere, their physical parameters and frequency, and its dependence on the solar cycle phase. We consider potential sources of ejections in the solar atmosphere and magnetic field configurations wherein the energy needed for sudden explosive acceleration of large masses of matter can be stored. The main instabilities of coronal structures that lead to the triggering and development of eruptive processes are analyzed. We show that coronal mass ejections are related to other manifestations of solar activity, while the eruptive processes observed using various techniques in various layer of the solar atmosphere and interplanetary space are the same phenomenon. We discuss indicators of the Sun's pre-eruptive regions approaching a catastrophe and the options to use them to forecast eruptions and space weather disturbances.