Features of the interaction of interplanetary coronal mass ejections/magnetic clouds with the Earth's magnetosphere

► ICME-magnetosphere interactions: key player is the low Alfven Mach number. ► Magnetosheath is a low-beta region in this case. ► Accelerated flows occur on draped field lines. ► ICME Interactions lead to intensified magnetopspheric disturbances. ► A 2-step great storm due to one such interaction.