The region located between the surface of the sun and its atmosphere has been revealed as a more violent place than previously¹ understood, according to images and data from NASA's newest solar observatory², the Interface³ Region Imaging Spectrograph, or IRIS⁴. Solar observatories⁵ look at the sun in layers. By capturing light emitted by atoms of different temperatures, they can focus in on different heights above the sun's surface extending well out into the solar atmosphere, the corona⁶（日冕）. On June 27, 2013, IRIS, was launched, to study what's known as the interface region -- a layer between the sun's surface and corona that previously was not well observed.

 

Over its first six months, IRIS has thrilled scientists with detailed⁷ images of the interface region, finding even more turbulence⁸（动荡） and complexity⁹ than expected. IRIS scientists presented the mission's early observations at a press conference at the Fall American Geophysical Union meeting on Dec. 9, 2013.

 

"The quality of images and spectra¹⁰ we are receiving from IRIS is amazing," said Alan Title, IRIS principal investigator¹¹ at Lockheed Martin in Palo Alto, Calif. "And we're getting this kind of quality from a smaller, less expensive mission, which took only 44 months to build."

 

For the first time, IRIS is making it possible to study the explosive phenomena¹² in the interface region in sufficient detail to determine their role in heating the outer solar atmosphere. The mission's observations also open a new window into the dynamics¹³ of the low solar atmosphere that play a pivotal（关键的） role in accelerating the solar wind and driving solar eruptive events.

 

Tracking the complex processes in the interface region requires instrument and modeling capabilities¹⁴ that are only now within our technological¹⁵ reach. IRIS captures both images and what's known as spectra, which display how much of any given wavelength¹⁶ of light is present. This, in turn, corresponds to how much material in the solar atmosphere is present at specific velocities¹⁷, temperatures and densities¹⁸. IRIS's success is due not only to its high spatial¹⁹ and temporal resolution, but also because of parallel development of advanced computer models. The combined images and spectra have provided new imagery of a region that was always known to be dynamic, but shows it to be even more violent and turbulent than imagined.

 

"We are seeing rich and unprecedented²⁰ images of violent events in which gases are accelerated to very high velocities while being rapidly heated to hundreds of thousands of degrees," said Bart De Pontieu, the IRIS science lead at Lockheed Martin. "These types of observations present significant challenges to current theoretical models."

点击收听单词发音