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 Computer model predicts how fracturing metallic glass releases energy at the atomic level
20.07.2018 | American Institute of Physics

nachricht What happens when we heat the atomic lattice of a magnet all of a sudden?
18.07.2018 | Forschungsverbund Berlin

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: Future electronic components to be printed like newspapers

A new manufacturing technique uses a process similar to newspaper printing to form smoother and more flexible metals for making ultrafast electronic devices.

The low-cost process, developed by Purdue University researchers, combines tools already used in industry for manufacturing metals on a large scale, but uses...

Im Focus: First evidence on the source of extragalactic particles

For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.

To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...

Im Focus: Magnetic vortices: Two independent magnetic skyrmion phases discovered in a single material

For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.

Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...

Im Focus: Breaking the bond: To take part or not?

Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.

A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...

Im Focus: New 2D Spectroscopy Methods

Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.

"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Conference on Laser Polishing – LaP: Fine Tuning for Surfaces

12.07.2018 | Event News

11th European Wood-based Panel Symposium 2018: Meeting point for the wood-based materials industry

03.07.2018 | Event News

 
Latest News

A smart safe rechargeable zinc ion battery based on sol-gel transition electrolytes

20.07.2018 | Power and Electrical Engineering

Reversing cause and effect is no trouble for quantum computers

20.07.2018 | Information Technology

Princeton-UPenn research team finds physics treasure hidden in a wallpaper pattern

20.07.2018 | Materials Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>