Solar Photosphere: Hot explosions on the cool sun

Sizzling star: Hot explosions in an active region of the Sun. 

In this image of the photosphere that was obtained at the end of September 2013 with the help of IRIS, the explosions are the bright spots. 

The image shows a sector with a size of 50,000 kilometers by 25 000 kilometers. 

Credit: NASA

The Sun is more spirited than previously thought. Apart from the solar eruptions, huge bursts of particles and radiation from the outer atmosphere of our star, also the cooler layer right below can be the site of explosions: in some areas magnetic energy builds up and discharges within only a few minutes in temperature eruptions of up to 100000 degrees.

Researchers under the lead of the Max Planck Institute for Solar System Research have now for the first time found evidence of such short-lived heat pockets in data from NASA's space telescope IRIS (Interface Region Imaging Spectrograph).

The Sun is an incredibly hot place, but even though in all its layers the temperatures are daunting, some are hotter than others.

With a temperature of approximately 5000 degrees, the Sun's visible surface, the photosphere, for example, is comparatively cool.

Going outward from there, the temperatures within the Sun's atmosphere rise, first moderately and then sharply, until they reach one million degrees.

"Our analysis shows, that this temperature distribution is not the same everywhere, and is constantly in motion", says Prof. Dr. Hardi Peter from the MPS, the paper's first author.

Together with an international team of scientists, Peter analyzed data from the space telescope IRIS taken from active regions on the Sun.

These regions within the photosphere are characterized by high magnetic field strengths and are the "birth places" of the dark sunspots, which cover the Sun's surface, at some times more, at others less abundantly.

"In these regions we found heat pockets as big as half of Germany. They are up to 20 times as hot as their surroundings", the astrophysicist describes. The heat pockets flash up for only minutes and then return to their normal state.

The amount of energy released during these explosions would be sufficient to provide all of Germany with electrical power for 8000 years.

The massive photospheric explosions cannot be spotted in visible light, but leave traces in the ultraviolet radiation the Sun emits into space.

IRIS can split this ultraviolet radiation into its constituting wavelengths more precisely than any other solar observatory before. In addition, it offers an unprecedented spatial resolution.

When IRIS opened its eyes to the Sun for the first time in July of last year, it could discern structures with a size of only 250 kilometers and examine radiation from such small regions separately.

"To our great surprise, we found well-defined areas within the active regions emitting radiation quite unlike the radiation from their vicinity", says Peter.

The researchers discovered characteristic wavelengths that special highly ionized atoms within the solar plasma such as triply ionized silicon ions emit into space.

"The presence of these wavelengths within the spectra points to very high temperatures", says Peter.

Only under such conditions can silicon loose three of its electrons, but in which of the Sun's layers did this temperature arise? Truly within the cool photosphere? Or maybe, and this would be much less spectacular, farther outside in the much hotter atmosphere?

The spectral data from IRIS proved to be so detailed that the researchers could extract further decisive clues.

For example, they were able to infer the density of the solar plasma where the radiation originated. In addition, they showed that the radiation had encountered singly-ionized iron ions on its way outward. These ions occur only in cooler regions.

"All in all, we found a coherent picture: the unusual radiation must originate in the cool outer photosphere" says Peter.

The researchers believe that the strong magnetic fields in the photosphere provide the necessary energy for the explosions.

In the area of the sun spots, the magnetic field lines protrude in a loop-like fashion from the Sun's surface; hot plasma flows there. When these flows are short-circuited, the explosions occur.

"The new results have fundamentally changed our understanding of the Sun's outer buildup", says Peter. "Instead of a stable temperature distribution, there are apparently dynamical processes within the cool photosphere that can turn everything topsy turvy."

Already in 1917, the American physicist Ferdinand Ellermann discovered areas with higher temperatures within the photosphere.

However, they differed from their surroundings only by a few thousand degrees and can therefore be considered rather minor temperature deviations. Whether the newly discovered explosions are linked to this phenomenon, is still unclear.

One of the other publications in Science magazine, to which scientists from the MPS have contributed, also paints a new picture of the processes on the Sun.

Researchers under the lead of the Harvard-Smithsonian Center for Astrophysics found that the solar wind, the continuous stream of particles from the Sun, does not leave the Sun's surface uniformly, but locally in highly energetic jets. These observations, too, are based on data from IRIS.

More information: 
H. Peter et al. "Hot Explosions in the Cool Atmosphere of the Sun." Science, 17 October 2014 - DOI: 10.1126/science.1255726

H. Tian et al. "Prevalence of Small-scale Jets from the Networks of the Solar Transition Region and Chromosphere." Science, 17 October 2014 - DOI: 10.1126/science.1255732

NASA SDO: IRIS captures New information about sun's atmosphere

NASA’s Solar Dynamics Observatory provided the outer image of a coronal mass ejection on May 9, 2014. 

The IRIS mission views the interface region that lies between the sun’s photosphere and corona in unprecedented detail for researchers to study.

Credit: NASA, Lockheed Martin Solar & Astrophysics Laboratory

NASA's Interface Region Imaging Spectrograph (IRIS) has provided scientists with five new findings into how the sun's atmosphere, or corona, is heated far hotter than its surface, what causes the sun's constant outflow of particles called the solar wind, and what mechanisms accelerate particles that power solar flares.

The new information will help researchers better understand how our nearest star transfers energy through its atmosphere and track the dynamic solar activity that can impact technological infrastructure in space and on Earth.

Details of the findings appear in the current edition of Science "On the prevalence of small-scale twist in the solar chromosphere and transition region"DOI: 10.1126/science.1255732

"These findings reveal a region of the sun more complicated than previously thought," said Jeff Newmark, interim director for the Heliophysics Division at NASA Headquarters in Washington.

"Combining IRIS data with observations from other Heliophysics missions is enabling breakthroughs in our understanding of the sun and its interactions with the solar system."

The first result identified heat pockets of 200,000 degrees Fahrenheit, lower in the solar atmosphere than ever observed by previous spacecraft.

Scientists refer to the pockets as solar heat bombs because of the amount of energy they release in such a short time.

Identifying such sources of unexpected heat can offer deeper understanding of the heating mechanisms throughout the solar atmosphere.

For its second finding, IRIS observed numerous, small, low lying loops of solar material in the interface region for the first time.

The unprecedented resolution provided by IRIS will enable scientists to better understand how the solar atmosphere is energized.

A surprise to researchers was the third finding of IRIS observations showing structures resembling mini-tornadoes occurring in solar active regions for the first time.

These tornadoes move at speeds as fast as 12 miles per second and are scattered throughout the chromosphere, or the layer of the sun in the interface region just above the surface.

These tornados provide a mechanism for transferring energy to power the million-degree temperatures in the corona.

Another finding uncovers evidence of high-speed jets at the root of the solar wind. The jets are fountains of plasma that shoot out of coronal holes, areas of less dense material in the solar atmosphere and are typically thought to be a source of the solar wind.

The final result highlights the effects of nanoflares throughout the corona. Large solar flares are initiated by a mechanism called magnetic reconnection, whereby magnetic field lines cross and explosively realign.

These often send particles out into space at nearly the speed of light. Nanoflares are smaller versions that have long been thought to drive coronal heating.

IRIS observations show high energy particles generated by individual nanoflare events impacting the chromosphere for the first time.

"This research really delivers on the promise of IRIS, which has been looking at a region of the sun with a level of detail that has never been done before," said De Pontieu, IRIS science lead at Lockheed Martin in Palo Alto, California.

"The results focus on a lot of things that have been puzzling for a long time and they also offer some complete surprises."

More Information
Science "On the prevalence of small-scale twist in the solar chromosphere and transition region"DOI: 10.1126/science.1255732

Solar Observatories Discovering a hidden source of solar surges

High-definition images of the Sun´s surface (left) and lower chromosphere (right) observed with the New Solar Telescope. 

This region of the Sun displays a some dark structures (solar pores) and the convective pattern (granulation) in which they are immersed. 

The region in the white circle is zoomed-out to show the action of the magnetic flux rope that interacts with the plasma and deforms the shape of the granules. 

At the lower part in the right image the scientists detected the ejection of a plasma surge extending thousands of miles.

Cutting-edge observations with the 1.6-meter telescope at Big Bear Solar Observatory (BBSO) in California have taken research into the structure and activity of the Sun to new levels of understanding.

Operated by New Jersey Institute of Technology (NJIT), the telescope at Big Bear is the most powerful ground-based instrument dedicated to studying the Sun.

A group of astronomers led by Dr. Santiago Vargas Dominguez has analyzed the highest- resolution solar observations ever made.

A summary of their work at BBSO was presented on June 2 at the 224th meeting of the American Astronomical Society, held in Boston, Massachusetts.

The NJIT researchers reported on the emergence of buoyant "small-scale" magnetic-flux ropes on the solar surface and the initiation of powerful plasma eruptions in the solar atmosphere.

The observations were performed as part of a program conducted jointly with NASA's Interface Region Imaging Spectrograph (IRIS) mission, Solar Dynamics Observatory (SDO) and Hinode satellite.

These observations provided a unique view of a magnetic-flux rope in the Sun's surface-granulation pattern that was 6,000 miles long, and the interaction between newly emergent and overlying ambient magnetic fields.

Solar activity entails numerous processes occurring in the star nearest to Earth. These processes have far-reaching effects, generating "space weather" that brings bursts of charged particles and high-energy radiation in the direction of Earth at nearly the speed of light.

Cartoon illustrating the action of a six-thousand miles long magnetic flux rope rising up from the solar interior and stretching the granules.  
The interaction between the emerged and the ambient magnetic fields produces impulsive heating and an ejection of a plasma surge.

The magnetic field generated in the solar interior and brought to the surface creates a wide variety of structures, with sunspots being the most well-known.

Sunspots can cover large areas of the surface of the Sun, up to several times the size of Earth. They can persist for weeks or even months before vanishing.

Associated with the evolution of sunspots, solar flares and coronal mass ejections are especially intense during the solar maximum, the period of greatest activity in the 11-year solar cycle.

Multiple phenomena can also occur on "smaller" spatial scales of several thousand miles, and in a matter of minutes.

Believed to be driven by the interaction of magnetic fields, these events occur with greater frequency and appear to be directly responsible for continuous heating of the solar atmosphere.

More information: "Multi-wavelength high-resolution observations of a small-scale emerging magnetic flux event and the chromospheric and coronal response." Santiago Vargas Dominguez, Alexander Kosovichev, Vasyl Yurchyshyn. arXiv:1405.3550 [astro-ph.SR]. arxiv.org/abs/1405.3550

NASA's IRIS: Observing a gigantic CME eruption of solar material

A coronal mass ejection, or CME, surged off the side of the sun on May 9, 2014, and NASA's newest solar observatory caught it in extraordinary detail. 

This was the first CME observed by the Interface Region Imaging Spectrograph (IRIS), which launched in June 2013 to peer into the lowest levels of the sun's atmosphere with better resolution than ever before. 

IRIS must commit to pointing at certain areas of the sun at least a day in advance, so catching a CME in the act involves some educated guesses and a little bit of luck.

"We focus in on active regions to try to see a flare or a CME," said Bart De Pontieu, the IRIS science lead at Lockheed Martin Solar & Astrophysics Laboratory in Palo Alto, California. "And then we wait and hope that we'll catch something. This is the first clear CME for IRIS so the team is very excited."

The IRIS imagery focuses in on material of 30,000 kelvins at the base, or foot points, of the CME.

The line moving across the middle of the movie is the entrance slit for IRIS's spectrograph, an instrument that can split light into its many wavelengths, a technique that ultimately allows scientists to measure temperature, velocity and density of the solar material behind the slit.

The field of view for this imagery is about five Earths wide and about seven-and-a-half Earths tall.


Watch the movie to see how a curtain of solar material erupts outward at speeds of 1.5 million miles per hour.

A coronal mass ejection burst off the side of the sun on May 9, 2014. The giant sheet of solar material erupting was the first CME seen by NASA's Interface Region Imaging Spectrograph (IRIS). 

The field of view seen here is about five Earths wide and about seven-and-a-half Earths tall. Credit: NASA/LMSAL/IRIS/SDO/Goddard

NASA SDO IRIS: Recording its largest Flare to date

On Jan. 28, 2014, NASA's Solar Observatory IRIS witnessed its strongest solar flare since it launched in the summer of 2013. Credit: NASA/IRIS

On Jan. 28, 2014, NASA's Interface Region Imaging Spectrograph (IRIS), witnessed its strongest solar flare since it launched in the summer of 2013.

Solar flares are bursts of x-rays and light that stream out into space, but scientists don't yet know the fine details of what sets them off.

IRIS peers, with unprecedented resolution, into a layer of the sun's lower atmosphere just above the surface, called the chromosphere, the second of the three main layers in the Sun's atmosphere that is roughly 2,000 kilometers deep.

However, IRIS can't look at the entire sun at the same time, so the team must always make decisions about what region might provide useful observations.

On Jan. 28, scientists spotted a magnetically active region on the sun and focused IRIS on it to see how the solar material behaved under intense magnetic forces.

At 2:40 p.m. EST, a moderate flare, labeled an M-class solar flare, which is the second strongest class flare after X-class solar flare, erupted from the area, sending light and x-rays into space.

IRIS studies the chromosphere, which is key to regulating the flow of energy and material as it travels from the sun's surface out into space.

Along the way, the energy heats up the upper atmosphere, the corona, and sometimes powers solar events such as this flare.

IRIS is equipped with an instrument called a spectrograph that can separate out the light it sees into its individual wavelengths, which in turn correlates to material at different temperatures, velocities and densities.

The spectrograph on IRIS was pointed right into the heart of this flare when it reached its peak, and so the data obtained can help determine how different temperatures of material flow, giving scientists more insight into how flares work.

On Jan. 28, 2014, NASA's recently-launched IRIS, observed its strongest solar flare to date. 

Credit: NASA /IRIS /SDO /Goddard Space Flight Center

The IRIS telescope was designed and built by the Smithsonian Astrophysical Observatory while Montana State University faculty and students assisted in the design of the spectrograph.

The Ames Pleiades supercomputer is used to carry out many of the numerical simulations that are led by the University of Oslo.

NASA IRIS: Providing unprecedented images of Sun

The fine detail in images of prominences in the sun's atmosphere from NASA's Interface Region Imaging Spectrometer (IRIS) -- such as the red swirls shown here -- are challenging the way scientists understand such events. 

Credit: NASA/LMSAL /IRIS

The region located between the surface of the sun and its atmosphere has been revealed as a more violent place than previously understood, according to images and data from NASA's newest solar observatory, the Interface Region Imaging Spectrograph, (IRIS).

Solar observatories 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 corona.

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 moths, IRIS has thrilled scientists with detailed images of the interface region, finding even more turbulence and complexity 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.

Alan Title

"The quality of images and spectra we are receiving from IRIS is amazing," said Alan Title, IRIS principal investigator 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 phenomena 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 dynamics of the low solar atmosphere that play a pivotal role in accelerating the solar wind and driving solar eruptive events.

Tracking the complex processes in the interface region requires instrument and modeling capabilities that are only now within our technological reach.

IRIS captures both images and what's known as spectra, which display how much of any given wavelength of light is present.

This, in turn, corresponds to how much material in the solar atmosphere is present at specific velocities, temperatures and densities.

IRIS's success is due not only to its high spatial 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.

This is an artist's concept of the Interface Region Imaging Spectrograph, or IRIS, satellite in orbit. Credit: NASA

"We are seeing rich and unprecedented 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."



This video compares the Solar Dynamics Observatory's (SDO) resolution with the Interface Region Imaging Spectrograph (IRIS) resolution for the same region of the Sun

NASA Telescope IRIS Snaps 1st Photos of Sun

A still image from the first movie captured by the IRIS solar observatory, 21 hours after mission controllers opened the telescope’s door.

Credit: NASA/IRIS

NASA's newest solar observatory has taken its first photos of the lowest layers of the solar atmosphere, a mysterious and little-understood region of the sun.

The images, taken just 21 hours after mission controllers first opened the telescope’s door, reveal new details of the sun’s lower atmosphere — an area known as the "interface region."

The IRIS spacecraft (short for Interface Region Imaging Spectrograph) captured images of thin magnetic structures and streams of material in the solar atmosphere.

These early observations suggest tremendous amounts of energy flow through the interface region, according to NASA officials.

"With this grand opening of the telescope door and first observations from IRIS, we've opened a new window into the energetics of the sun's atmosphere," John Grunsfeld, associate administrator of the Science Mission Directorate at NASA Headquarters in Washington, D.C., said in a statement. "We look forward to the new insights IRIS will provide."

Orbital Science: Preparation of NASA IRIS on Pegasus XL Launcher

Orbital Sciences team members move the second half of the payload fairing before it is placed over NASA's IRIS (Interface Region Imaging Spectrograph) spacecraft. 

The fairing connects to the nose of the Orbital Sciences Pegasus XL rocket that will lift the solar observatory into orbit. 

The work is taking place in a hangar at Vandenberg Air Force Base, where IRIS is being prepared for launch on a Pegasus XL rocket. 

Scheduled for launch from Vandenberg on June 26, 2013, IRIS will open a new window of discovery by tracing the flow of energy and plasma through the chromospheres and transition region into the sun's corona using spectrometry and imaging. 

IRIS fills a crucial gap in our ability to advance studies of the sun-to-Earth connection by tracing the flow of energy and plasma through the foundation of the corona and the region around the sun known as the heliosphere. 

Photo Credit: NASA/Tony Vauclin

JAXA’s Hinode mission Image Solar Interface Region

This image from the Japan Aerospace Exploration Agency’s Hinode mission shows the lower regions of the sun’s atmosphere, the interface region.

A new NASA mission called the Interface Region Imaging Spectrograph (IRIS), will study in greater detail.

Where previous missions have been able to image material at only a few predetermined temperatures in this region, IRIS will observe a wide range of temperatures from 5,000 kelvins to 65,000 kelvins (8,540 F to 116,540 F), and up to 10 million kelvins (about 18 million F) during solar flares.

Its images will resolve structures down to 150 miles across. Image credit: JAXA/Hinode

NASA IRIS: Preparation for Launch of Next Solar Satellite

This is a photo of the complete IRIS observatory with the solar arrays deployed. 

This is taken in a large clean tent at Lockheed Martin prior to vibration testing and prior to installation of the flight MLI blankets. 

The solar arrays have just been deployed using flight commands. 

Image credit: LM Photo

NASA's next scientific satellite, which is scheduled for launch June 26, will provide the most detailed look ever at the sun's lower atmosphere or interface region.

The Interface Region Imaging Spectrograph (IRIS) mission will observe how solar material moves, gathers energy, and heats up as it travels through this largely unexplored region of the solar atmosphere.

The interface region, located between the sun's visible surface and upper atmosphere, is where most of the sun's ultraviolet emission is generated. These emissions impact the near-Earth space environment and Earth's climate.

The IRIS spacecraft was designed and built by Lockheed Martin's Advanced Technology Center. It will launch aboard a Pegasus XL rocket deployed by an Orbital Sciences L-1011 aircraft from Vandenberg Air Force Base on the central California coast.

"IRIS data will fill a crucial gap in our understanding of the solar interface region upon joining our fleet of heliophysics spacecraft," said Jeffrey Newmark, NASA's IRIS program scientist in Washington.

"For the first time we will have the necessary observations for understanding how energy is delivered to the million-degree outer solar corona and how the base of the solar wind is driven."

IRIS carries an ultraviolet telescope that feeds a multi-channel imaging spectrograph. The satellite is the first mission designed to use an ultraviolet telescope to obtain high-resolution images and spectra every few seconds and provide observations of areas as small as 150 miles across the sun.

"Previous observations suggest there are structures in this region of the solar atmosphere 100 to 150 miles wide, but 100,000 miles long," said Alan Title, IRIS principal investigator at Lockheed Martin.

"Imagine giant jets like huge fountains that have a footprint the size of Los Angeles and are long enough and fast enough to circle Earth in 20 seconds.

IRIS will provide our first high-resolution views of these structures along with information about their velocity, temperature and density."

After launch, IRIS will travel in a polar, sun-synchronous orbit around Earth, crossing nearly directly over the poles in such a way that it moves over the equator at the same local time each day.

The spacecraft will orbit at an altitude range of 390 miles to 420 miles. This orbit allows for almost continuous solar observations on IRIS' two-year mission.

IRIS' unique capabilities will be coupled with state of the art 3-D numerical modeling on supercomputers, such as Pleiades, housed at NASA’s Ames Research Center in Moffett Field, Calif.

Recent improvements in the power of supercomputers, such as Pleiades, to analyze large amounts of data will enable IRIS to provide better information about the region than ever before.

NASA IRIS Solar Satellite: Launch from Vandenberg AFB

Interface Region Imaging Spectograph (IRIS) satellite with solar wings deployed in in Lockheed Martin Space Systems Company in Sunnyvale, Calif.


Workers unload NASA's IRIS spacecraft from a truck at the processing facility at Vandenberg where the spacecraft will be readied for launch aboard an Orbital Sciences Pegasus XL rocket. 

Photo credit: VAFB/Randy Beaudoin

Scientists will soon gain a better view into energy and plasma movement near the surface of the sun, thanks to delivery of the Interface Region Imaging Spectrograph (IRIS) spacecraft to Vandenberg Air Force Base, Calif. in preparation for launch.

Part of NASA's Small Explorer (SMEX) Mission, which delivers space exploration missions costing less than $120 million, IRIS was designed and built at Lockheed Martin's Space Systems Company Advanced Technology Center (ATC) in Palo Alto, Calif.

The launch of IRIS will not take place before May 28.

"The entire IRIS team is enormously pleased that we've reached this crucial milestone," said Gary Kushner, Lockheed Martin IRIS program manager.

"After many months of hard work by the Lockheed Martin team and all of our collaborators and subcontractors in designing, engineering, building and testing the instrument and integrated spacecraft, our goal of putting it into orbit is in sight and we look forward to producing great science at a low cost."

"The IRIS spacecraft and instrument are emblematic of the wide range of capabilities that Lockheed Martin brings to the exploration and utilization of space," said Dr. Kenneth Washington, vice president of the ATC.

"The IRIS solar telescope is the latest in a five decade heritage of sensing payloads which, cumulatively, have operated for over 800 years in space. Moreover, our small satellite capabilities have supported multiple successful missions including IKONOS, Lunar Prospector, IMAGE, and now IRIS."

The goal of the IRIS program is to better understand how energy and plasma move from a lower layer of the sun's surface called the photosphere, through the chromosphere layer and to the outer corona layer.

IRIS: NASA's Interface Region Imaging Spectrograph Mission Satellite Completed

The fully integrated spacecraft and science instrument for NASA's Interface Region Imaging Spectrograph (IRIS) mission is seen in a cleanroom at the Lockheed Martin Space Systems Sunnyvale, Calif. facility. 

The solar arrays are deployed in the configuration they will assume when in orbit.

The spacecraft and science instrument integration for the Interface Region Imaging Spectrograph (IRIS) - NASA's next Small Explorer (SMEX) Mission - has been completed, and final testing is underway.

NASA's Ames Research Center, Moffett Field, Calif., is responsible for mission operations and the ground data system.

The Norwegian Space Agency will capture the IRIS data with their antennas in Svalbard, inside the Arctic Circle, in northern Norway.

The science data will be managed by the Joint Science Operations Center of the Solar Dynamics Observatory, run by Stanford and Lockheed Martin.

"The entire IRIS team is enormously pleased that we've reached this crucial milestone," said Gary Kushner, Lockheed Martin IRIS program manager. "

After many months of hard work by the Lockheed Martin team and all of our collaborators and subcontractors in designing, engineering and building the instrument and spacecraft bus, our goal of putting it into orbit is in sight and we look forward to producing great science at a low cost."

Understanding the interface between the photosphere and corona remains a fundamental challenge in solar and heliospheric science.

The IRIS mission will open a window of discovery into this crucial region by tracing the flow of energy and plasma through the chromosphere and transition region into the corona using spectrometry and imaging.

Here all but a few percent of the non-radiative energy leaving the Sun is converted to heat and radiation. The remaining few percent create the corona and solar wind.

Magnetic fields and plasma exert comparable forces in this region, and IRIS is uniquely suited to provide the observations necessary to pinpoint the physical forces at work in this little understood piece of real estate near the surface of the Sun.

"The interpretation of the IRIS spectra is a major effort coordinated by the IRIS Science Team that will utilize the full extent of the power of the most advanced computational resources in the world.

"It is this new capability, along with development of state of the art codes and numerical models by the University of Oslo that capture the complexities of this region, which make the IRIS mission possible.

Without these important elements we would be unable to fully interpret the IRIS spectra," said Dr. Alan Title, IRIS principal investigator and physicist at the ATC Solar and Astrophysics Laboratory in Palo Alto.