CME stands for "Coronal Mass Ejection". They are explosions that take place near the surface of the sun. When this happens plasma is ejected out from the sun's surface. A significant amount of plasma can be hurled out into space during episodes of CME. The sun's magnetic field is the basis for these eruptions - or at least plays a major role in why CME's occur.
The sun's magnetic field gets twisted because of the fluid make up of the sun. This causes diverse configurations of this magnetic field. However, these configurations of the field can be very extreme, causing a snap or break in the magnetic field. The result of this break is a CME and the subsequent catapulting of charged, magnetic field-inducing particles and gas from the outer coronal layer.
Some of these CMEs can affect the Earth as they cross into the Earth's orbit. One effect is that they can disrupt power grids and cause trouble with communication systems on earth. These CMEs can also affect the performance of satellites in orbit way above the Earth. Furthermore, astronauts may be subject to increased doses of radiation if they are caught in the path of one of these ejections during a mission - in fact, they can be exposed to deadly doses.
Ok! When it occured?