Understanding how the energy travels through this region – energy that helps heat the upper layer of the atmosphere, the corona, to temperatures of 1,000,000 kelvins, some thousand times hotter than the sun’s surface itself – is the goal of NASA's Interface Region Imaging Spectrograph, or IRIS, scheduled to launch on June 26, 2013 from California's Vandenberg Air Force Base.
Scientists wish to understand the interface region in exquisite detail, since energy flowing through this region has an effect on so many aspects of near-Earth space. For one thing, despite the intense amount of energy deposited into the interface region, only a fraction leaksthrough, but this fraction drives the solar wind, the constant stream of particles that flows out to fill the entire solar system. The interface region is also the source of most of the sun's ultraviolet emission, which impacts both the near-Earth space environment and Earth's climate.
IRIS's capabilities are uniquely tailored to unravel the interface region by providing both high-resolution images and a kind of data known as spectra, which can see many wavelengths at once. For its high-resolution images, IRIS will capture data on about one percent of the sun at a time. While these are relatively small snapshots, IRIS will be able to see very fine features, as small as 150 miles across.