For some reason, the temperature increases dramatically throughout the Transition Region. The Sun's surface is a mere 5,000 degrees Kelvin. But 100,000 kilometers out into the Corona, the temperature jumps to nearly 2 million degrees Kelvin. Again, scientists believe that the action of the Sun's magnetic field has something to do with it. A solar flare is a sudden eruption of energy on the Sun's surface.
Flares are important.
Even though they do not make any noticeable change in the brightness of the Sun, they can have an effect on our lives here on Earth. While they only last a couple of minutes, large flares on the Sun throw out sudden bursts of high energy radiation which can disrupt and even damage communications system on Earth. Once again, solar physicists believe that disruptions in the Sun's powerful magnetic field plays an important role in the creation of solar flares.