Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

NASA's SDO Mission Untangles Motion Inside the Sun

29.08.2013
Using an instrument on NASA's Solar Dynamics Observatory, called the Helioseismic and Magnetic Imager, or HMI, scientists have overturned previous notions of how the sun's writhing insides move from equator to pole and back again, a key part of understanding how the dynamo works. Modeling this system also lies at the heart of improving predictions of the intensity of the next solar cycle.

Using SDO, scientists see a performance of explosions and fountains on the solar surface. Shots of solar material leap into the air. Dark blemishes called sunspots grow, combine and disappear as they travel across the sun's face. Bright loops of charged particles – captured by magnetic fields dancing around the sun – hover in the atmosphere.


Observations by the Helioseismic and Magnetic Imager on NASA's Solar Dynamics Observatory show a two-level system of circulation inside the sun. Such circulation is connected to the flip of the sun's north and south magnetic poles that occurs approximately every 11 years. Image Credit: Stanford

This dynamic display is all powered by a complex, ever-changing magnetic current inside the sun known as the dynamo. This magnetic system flips approximately every 11 years, with magnetic north and magnetic south switching poles. This process is an integral part of the sun's progression toward a pinnacle of solar activity, known as solar maximum.

The team's recent results show that, instead of a simple cycle of flow moving toward the poles near the sun's surface and then back to the equator, the material inside the sun shows a double layer of circulation, with two such cycles on top of each other. The results appear online in the Astrophysical Journal Letters on Aug. 27, 2013.

"For decades people have known that the solar cycle depends on the poleward flow or material, changing the magnetic fields from one cycle to the next," said Philip Scherrer, principal investigator for HMI at Stanford University in Stanford, Calif. "We mapped out what we believed to be the flow pattern in the 1990s, but the results didn't quite make sense."

Since the mid-1990s researchers have been observing movement inside the sun using a technique called helioseismology. The technique makes use of the fact that waves course across the sun, back and forth, oscillating with an approximately five minute period. Such waves are similar to the seismic waves that spread out under the ground during an earthquake. By monitoring the oscillations seen at the surface of the sun, scientists can gather information about the material through which the waves traveled, including what the material is made of and how fast and in what direction it is moving.

Such observations quickly showed scientists how material inside the sun rotates from east to west: material moves more slowly at the poles than it does at the equator. The observations also soon showed that material moved from the equators toward the poles within the top 20,000 miles of the sun's surface – but the flow back toward the equator from the poles was not detected. Early models of all this moving material, therefore, assumed that the equator-ward flow was much lower, only occurring at the bottom of the convection layer of the sun that houses these flows, some 125,000 miles down.

"Scientists have used this assumption to describe the solar dynamo," said Junwei Zhao, a helioseismologist at Stanford University in Stanford, Calif., who is the first author on the paper. "And now we have found that it isn't right. The flow patterns we have found are sharply different."

Zhao and his colleagues observed two years worth of data from HMI, which differs from one of the best previous helioseismology instruments – the Michelson Doppler Imager on board the joint European Space Agency/NASA mission the Solar and Heliospheric Observatory, or SOHO. SOHO observed the sun in low resolution on a regular basis, but only observed it in high resolution for a couple months each year. HMI observes the sun continuously with 16 times more detail than SOHO.

Using this data, Zhao compared the helioseismology results measured at four different heights within the sun's surface, and found these results were not consistent with what the normal convention would expect. The team proposed a way to make these four sets of measurements agree with each other.

This new method not only brought the four data sets into harmony, but also helped find the long-sought equatorward flow inside the sun. The team found that the flow toward the poles does indeed occur in a layer at near the sun's surface – but the equatorward flow isn't at the bottom. Instead, the material seeps back toward the equator through the middle of the convection layer. Moreover, deep down inside the layer is a second stream of material moving toward the poles, making what the scientists refer to as a double-cell system in which two oblong flow systems are stacked on top of each other.

"This has important consequences for modeling the solar dynamo," said Zhao. "We hope our results on the sun's interior flow will provide a new opportunity to study the generation of solar magnetism and solar cycles."

Zhao and his colleagues have provided their new map of the sun's interior to scientists who simulate the dynamo. The next steps will be to see how such new models jibe with the observations seen on the sun and how it may improve our ability to understand the constant dance of magnetism on the sun.

For more information about NASA's SDO, visit:
www.nasa.gov/sdo
Karen C. Fox
NASA's Goddard Space Flight Center, Greenbelt, Md.

Karen C. Fox | EurekAlert!
Further information:
http://www.nasa.gov
http://www.nasa.gov/content/goddard/sdo-mission-untangles-motion-inside-sun/#.Uh5iEXf3Mg8

More articles from Physics and Astronomy:

nachricht Witnessing turbulent motion in the atmosphere of a distant star
23.08.2017 | Max-Planck-Institut für Radioastronomie

nachricht Heating quantum matter: A novel view on topology
22.08.2017 | Université libre de Bruxelles

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Fizzy soda water could be key to clean manufacture of flat wonder material: Graphene

Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.

As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...

Im Focus: Exotic quantum states made from light: Physicists create optical “wells” for a super-photon

Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.

Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...

Im Focus: Circular RNA linked to brain function

For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.

While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...

Im Focus: RAVAN CubeSat measures Earth's outgoing energy

An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.

The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...

Im Focus: Scientists shine new light on the “other high temperature superconductor”

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.

Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Call for Papers – ICNFT 2018, 5th International Conference on New Forming Technology

16.08.2017 | Event News

Sustainability is the business model of tomorrow

04.08.2017 | Event News

Clash of Realities 2017: Registration now open. International Conference at TH Köln

26.07.2017 | Event News

 
Latest News

What the world's tiniest 'monster truck' reveals

23.08.2017 | Life Sciences

Treating arthritis with algae

23.08.2017 | Life Sciences

Witnessing turbulent motion in the atmosphere of a distant star

23.08.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>