coronal mass ejection

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A very large emission of plasma from the sun that disrupts the flow of the solar wind, sometimes interfering with the operation of artificial satellites, electronic communications, and electric power transmission on Earth.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun A massive burst of solar wind, other light isotope plasma, and magnetic fields rising above the solar corona or being released into space.