Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Seasonal, year-long cycles seen on the Sun

09.04.2015

Our sun is constantly changing. It goes through cycles of activity - swinging between times of relative calm and times when frequent explosions on its surface can fling light, particles and energy out into space. This activity cycle peaks approximately every 11 years. New research shows evidence of a shorter time cycle as well, with activity waxing and waning over the course of about 330 days.

Understanding when to expect such bursts of solar activity is crucial to successfully forecast the sun's eruptions, which can drive solar storms at Earth. These space weather events can interfere with satellite electronics, GPS navigation, and radio communications. The quasi-annual variations in space weather seem to be driven by changes in bands of strong magnetic field that are present in each solar hemisphere, said researchers in a paper published on April 7, 2015, in Nature Communications.


Bands of magnetized solar material march toward the sun's equator. The way the bands in each hemisphere interact leads to a 330-day cycle of waxing and waning activity on the sun that can be as strong as the more well-studied 11-year solar cycle.

Credit: S. McIntosh

"What we're looking at here is a massive driver of solar storms," said Scott McIntosh, lead author of the paper and director of the High Altitude Observatory of the National Center for Atmospheric Research in Boulder, Colorado. "By better understanding how these activity bands form in the sun and cause these seasonal instabilities, we can greatly improve forecasts of space weather."

The new study is one of several by the research team to examine what creates the magnetic bands and how they influence solar cycles. McIntosh and his co-authors detected the bands by drawing on a host of NASA satellites and ground-based observatories that observe the sun and its output -- from the constant flow of particles in the solar wind to large explosions such as solar flares or giant eruptions of solar material called coronal mass ejections, or CMEs.

The scientists note that the changes in the magnetic field in the bands gives rise to a 330-day activity cycle on the sun that is observable but has often been downplayed and overlooked when trying to seek the cause of the sun's longer, 11-year cycle.

"People have not paid much attention to this nearly-annual cycle," said McIntosh. "But it's such a driver of space weather that we really do need to focus on it. Cycles over this time frame are observed in all sorts of output from the sun: the sun's radiance, the solar wind, solar flares, CMEs."

Magnetic band interaction can also help explain a puzzle first discovered in the 1960s: Why does the number of powerful solar flares and CMEs peak a year or more after the maximum number of sunspots? This lag is known as the Gnevyshev Gap, after the Soviet scientist who first noticed the pattern. The answer appears to also depend on two activity bands.

Having one band located in each solar hemisphere provides an opportunity for them to mix -- magnetic field from one band effectively leaking into the other -- creating more unstable active regions on the sun and leading to more flares and CMEs. In other papers, scientists have shown that this process happens only after the sunspot maximum.

In doing their analysis on band interaction the scientists noticed that the bands themselves undergo strong quasi-annual variations, taking place separately in both the northern and southern hemispheres. Those quasi-annual variations in magnetism could be almost as large in magnitude as those of the more familiar, approximately 11-year solar cycle, giving rise to the appearance of stormy seasons.

"The activity bands on the sun have very slow-moving waves that can expand and warp," said Robert Leamon, co-author on the paper at Montana State University in Bozeman and NASA Headquarters in Washington. "Sometimes this results in magnetic field leaking from one band to the other. In other cases, the warp drags magnetic field from deep in the solar interior and pushes it toward the surface."

The surges of magnetic fuel from the sun's interior can catastrophically destabilize the existing corona, the sun's outermost atmosphere. They are a driving force behind the most intense solar storms.

Researchers can turn to advanced computer simulations and focused observations to learn more about the influence of these bands on solar activity. McIntosh suggested that this could be assisted by a proposed network of satellites observing the sun, much as the global networks of satellites around Earth has significantly advanced terrestrial weather models since the 1960s.

"If you understand what the patterns of solar activity are telling you, you'll know whether we're in a stormy phase or quiet phase in each hemisphere," McIntosh said. "If we can combine these pieces of observational information with modeling efforts, then space weather forecast skill can go through the roof."

###

The research was funded by NASA and the National Science Foundation, which is NCAR's sponsor.

For more information on the sun's magnetic activity bands:

http://www.nasa.gov/content/goddard/researchers-discover-new-clues-to-determining-the-solar-cycle/

Susan Hendrix | EurekAlert!

More articles from Physics and Astronomy:

nachricht Astronomers find unexpected, dust-obscured star formation in distant galaxy
24.03.2017 | University of Massachusetts at Amherst

nachricht Gravitational wave kicks monster black hole out of galactic core
24.03.2017 | NASA/Goddard Space Flight Center

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: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

Im Focus: Researchers Imitate Molecular Crowding in Cells

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

Argon is not the 'dope' for metallic hydrogen

24.03.2017 | Materials Sciences

Astronomers find unexpected, dust-obscured star formation in distant galaxy

24.03.2017 | Physics and Astronomy

Gravitational wave kicks monster black hole out of galactic core

24.03.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>