NASA has released spectacular UV images taken from its Transition Region Coronal Explorer spacecraft. They show arches of fire (coronal loops) streaming 320,000km (200,000 miles) into the solar corona. At 3 million °C (5 million °F), they are much hotter than the 10,000°C Sun surface. Also, heat is applied near the bottom of the arches, about 16,000km above the surface, rather than along their entire length.
Source: Flight International