Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

NCAR researcher sheds light on solar storms

31.05.2005


New research from the National Center for Atmospheric Research (NCAR) links a particular magnetic structure on the Sun with the genesis of powerful solar storms that can buffet Earth’s atmosphere. The research may enable scientists to create more accurate computer models of the solar storms, known as coronal mass ejections (CMEs), and could eventually point the way to forecasting the storms days before they occur. Sarah Gibson, a scientist at NCAR’s High Altitude Observatory (HAO), will present her findings at the American Geophysical Union conference in New Orleans on Thursday, May 26. Her invited talk is in recognition of winning this year’s Karen Harvey Prize. Awarded by the Solar Physics Division of the American Astronomical Society, the prize recognizes an early-career scientist who has produced exceptional solar research. CMEs are a focus of solar research because they suddenly and violently release billions of tons of matter and charged particles that escape from the Sun and speed through space. Ejections pointed toward Earth can set off disturbances when they reach the upper atmosphere, affecting satellites, ground-based communications systems, and power grids.



For her research, Gibson turned to a unique data set: white-light images of the lower reaches of the Sun’s enormous halo, called the corona. Taken by NCAR’s Mark-IV K-Coronameter on Mauna Loa in Hawaii, the images are sensitive to density alone, avoiding the ambiguity of most other solar images that depend on both temperature and density. The images revealed that lower-density regions in the corona consistent with twisted magnetic field lines can form prior to a CME. The twisted areas, known as magnetic flux ropes, store massive amounts of energy.

"The structures indicate a magnetic system that has enough energy to fuel a CME," Gibson explains. "But their presence is not, by itself, an indication that a CME is about to occur. For that, we need to look at additional characteristics."


The research may put to rest an important debate among solar physicists over whether magnetic flux ropes can form prior to an ejection or are merely present when an ejection takes place. Gibson’s findings suggest that, to understand the forces that create CMEs, solar scientists should use magnetic flux ropes as starting points for computer models of the massive storms.

To conduct her study, Gibson used Mark-IV images to observe dark, lower-density areas, known as cavities, that can be formed by the strong, sheared magnetic fields of magnetic flux ropes. She and NCAR colleagues analyzed 13 cavity systems from November 1999 to January 2004. Seven of these systems could be associated with CMEs, and four cavities were directly observed by the coronameter to erupt as CMEs. Gibson used a second technique to identify an additional eight CMEs that erupted from already-formed cavities. She found those cases by gathering images of CMEs and backtracking to see whether cavities existed at those CME sites before each eruption.

One of Gibson’s next steps will be to analyze cavities that result in CMEs to determine whether they have identifiable characteristics that may help scientists forecast a CME. Her preliminary findings indicate that a cavity begins to bulge and rise higher in the corona just before erupting. Cavities may also darken and become more sharply defined prior to eruption.

Gibson will also try to determine how widespread cavities are, and if it is possible that most, or even all, CMEs are preceded by the formation of magnetic flux ropes. Beginning next year, she will supplement the Mauna Loa observations with data from a pair of new NASA satellites, known as STEREO (Solar Terrestrial Relations Observatory). Instruments aboard STEREO will provide stereoscopic measurements and 24-hour coverage of the lower solar corona, significantly increasing the chances of directly observing cavities erupting into CMEs.

Anatta | EurekAlert!
Further information:
http://www.ucar.edu

More articles from Physics and Astronomy:

nachricht Tiny lasers from a gallery of whispers
20.09.2017 | American Institute of Physics

nachricht New quantum phenomena in graphene superlattices
19.09.2017 | Graphene Flagship

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: Tiny lasers from a gallery of whispers

New technique promises tunable laser devices

Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...

Im Focus: Ultrafast snapshots of relaxing electrons in solids

Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!

When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...

Im Focus: Quantum Sensors Decipher Magnetic Ordering in a New Semiconducting Material

For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.

Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...

Im Focus: Fast, convenient & standardized: New lab innovation for automated tissue engineering & drug

MBM ScienceBridge GmbH successfully negotiated a license agreement between University Medical Center Göttingen (UMG) and the biotech company Tissue Systems Holding GmbH about commercial use of a multi-well tissue plate for automated and reliable tissue engineering & drug testing.

MBM ScienceBridge GmbH successfully negotiated a license agreement between University Medical Center Göttingen (UMG) and the biotech company Tissue Systems...

Im Focus: Silencing bacteria

HZI researchers pave the way for new agents that render hospital pathogens mute

Pathogenic bacteria are becoming resistant to common antibiotics to an ever increasing degree. One of the most difficult germs is Pseudomonas aeruginosa, a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

“Lasers in Composites Symposium” in Aachen – from Science to Application

19.09.2017 | Event News

I-ESA 2018 – Call for Papers

12.09.2017 | Event News

EMBO at Basel Life, a new conference on current and emerging life science research

06.09.2017 | Event News

 
Latest News

Molecular Force Sensors

20.09.2017 | Life Sciences

Producing electricity during flight

20.09.2017 | Power and Electrical Engineering

Tiny lasers from a gallery of whispers

20.09.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>