Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

External Magnetic Field Causes The Puzzling Heating Of The Solar Corona

21.06.2002


The Russian astrophysicists have theoretically modelled coronal loop oscillations and have shown that the plasma present in coronal loops is quite "normal". So, the puzzle of the Sun`s atmosphere heating remains unresolved.



Coronal loops, immense magnetic arches more hot and dense than the coronal gas, are formed by magnetic fields. They are anchored in the Sun`s visible surface rising up to 100 - 200 thousand kilometres. In the active regions of the Sun these loops, which are 1000 - 3000 kilometres in diameter, form bunches and tangles.

In 1998 the American Transition Region and Coronal Explorer (TRACE) spacecraft with the imaging telescope onboard has been launched. Images of hot coronal loops were obtained and researchers observed oscillations of coronal loops near the epicentre of a solar flare. But these oscillations were damped quickly within a few oscillation periods in the way the process occurred not in the rare coronal plasma but in the rather viscous environment resembling honey.


Calculations made by the American scientists showed that the viscosity of the coronal plasma was billion times higher than supposed. And if the plasma is so viscous, its conductivity must be billion times lower than in the normal one and electric currents related with magnetic fields would effectively damp in this kind of plasma. And such a mechanism can cause heating of the solar corona.

After studying the images obtained by TRACE spacecraft the Russian scientists have made a physical model which describes loop oscillations in the plasma of normal density but they introduced in their model an external magnetic field. They saw that a loop oscillating with observed amplitude transforms all energy of the primary boost into the wave energy dissipation in the environment during only two or three periods of oscillation. What can be the cause of such a magnetic field? Nobody can measure magnetic fields in the coronal plasma. "We have made an assumption. Gas density and temperature in a loop are higher than in its environment, so a force exists that protects the loop from simultaneous disintegration. Only pressure of external magnetic field can play the role of such a force", says Alexander Solovjev who leads the Russian research team. According to Solovjev, the puzzle of the Sun`s corona heating remains unresolved prompting new theories and hypotheses.

Tatiana Pitchugina | alfa
Further information:
http://www.informnauka.ru/eng/2002/2002-06-21-02_140_e.htm

More articles from Physics and Astronomy:

nachricht New NASA study improves search for habitable worlds
20.10.2017 | NASA/Goddard Space Flight Center

nachricht Physics boosts artificial intelligence methods
19.10.2017 | California Institute of Technology

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: Neutron star merger directly observed for the first time

University of Maryland researchers contribute to historic detection of gravitational waves and light created by event

On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...

Im Focus: Breaking: the first light from two neutron stars merging

Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.

Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....

Im Focus: Smart sensors for efficient processes

Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).

When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...

Im Focus: Cold molecules on collision course

Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.

How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...

Im Focus: Shrinking the proton again!

Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.

It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ASEAN Member States discuss the future role of renewable energy

17.10.2017 | Event News

World Health Summit 2017: International experts set the course for the future of Global Health

10.10.2017 | Event News

Climate Engineering Conference 2017 Opens in Berlin

10.10.2017 | Event News

 
Latest News

NRL clarifies valley polarization for electronic and optoelectronic technologies

20.10.2017 | Interdisciplinary Research

Metallic nanoparticles will help to determine the percentage of volatile compounds

20.10.2017 | Materials Sciences

Shallow soils promote savannas in South America

20.10.2017 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>