What is a CME? http://en.wikipedia.org/wiki/Coronal_mass_ejection
A coronal mass ejection (CME) is a massive burst of solar wind and magnetic fields rising above the solar corona or being released into space.
Coronal mass ejections are often associated with other forms of solar activity, most notably solar flares, but a causal relationship has not been established. Most ejections originate from active regions on the Sun's surface, such as groupings of sunspots associated with frequent flares. Near solar maxima, the Sun produces about three CMEs every day, whereas near solar minima, there is about one CME every five days.
Coronal mass ejections release huge quantities of matter and electromagnetic radiation into space above the sun's surface, either near the corona (sometimes called a solar prominence), or farther into the planet system, or beyond (interplanetary CME). The ejected material is a plasma consisting primarily of electrons and protons, but may contain small quantities of heavier elements such as helium, oxygen, and even iron. The theory of heavier element emissions during a CME is speculative information and requires further verification. It is highly unlikely that a CME contains any substantial amount of heavier elements, especially considering that the sun has not yet arrived at the point of helium flash and thus cannot begin to fuse elements heavier than helium.
Coronal mass ejections are associated with enormous changes and disturbances in the coronal magnetic field. They are usually observed with a white-light coronagraph.When the ejection is directed towards the Earth and reaches it as an interplanetary CME (ICME), the shock wave of the traveling mass of Solar Energetic Particles causes a geomagnetic storm that may disrupt the Earth's magnetosphere, compressing it on the day side and extending the night-side magnetic tail. When the magnetosphere reconnects on the nightside, it releases power on the order of terawatt scale, which is directed back toward the Earth's upper atmosphere.
Solar Energetic Particles can cause particularly strong aurorae in large regions around Earth's magnetic poles. These are also known as the Northern Lights (aurora borealis) in the northern hemisphere, and the Southern Lights (aurora australis) in the southern hemisphere. Coronal mass ejections, along with solar flares of other origin, can disrupt radio transmissions and cause damage to satellites and electrical transmission line facilities, resulting in potentially massive and long-lasting power outages.
Humans in space or at high altitudes, for example, in airplanes, risk exposure to relatively intense so-called cosmic rays. Cosmic rays are potentially lethal in high quantities. The energy absorbed by the astronaut is not reduced by a typical spacecraft shield design and, if any protection is provided for the astronaut, it would result from changes in the microscopic inhomogeneity of the energy absorption events.
What is the recent news about CME's? http://www.spaceweather.com/
WEAK IMPACT, NICE AURORAS: A minor CME hit Earth's magnetic field on July 9th at approximately 20:30 UT. The impact was weak, and at first had little effect, but in the hours following the strike a geomagnetic storm developed. At its peak during the early hours of July 10th, the G1-class storm produced auroras in northern-tier US states from Wisconsin to Washington. Jim Reitz sends this picture from Rattlesnake Lake, about 30 miles east of Seattle:
Speedy tsunami seen on Sun's surface http://www.bbc.co.uk/news/science-environment-23241896