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 Long-lived storage of a photonic qubit for worldwide teleportation
12.12.2017 | Max-Planck-Institut für Quantenoptik

nachricht Telescopes team up to study giant galaxy
12.12.2017 | International Centre for Radio Astronomy Research

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: Electromagnetic water cloak eliminates drag and wake

Detailed calculations show water cloaks are feasible with today's technology

Researchers have developed a water cloaking concept based on electromagnetic forces that could eliminate an object's wake, greatly reducing its drag while...

Im Focus: Scientists channel graphene to understand filtration and ion transport into cells

Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.

To rapidly transport the right ions through the cell membrane, the tiny channels rely on a complex interplay between the ions and surrounding molecules,...

Im Focus: Towards data storage at the single molecule level

The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.

Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...

Im Focus: Successful Mechanical Testing of Nanowires

With innovative experiments, researchers at the Helmholtz-Zentrums Geesthacht and the Technical University Hamburg unravel why tiny metallic structures are extremely strong

Light-weight and simultaneously strong – porous metallic nanomaterials promise interesting applications as, for instance, for future aeroplanes with enhanced...

Im Focus: Virtual Reality for Bacteria

An interdisciplinary group of researchers interfaced individual bacteria with a computer to build a hybrid bio-digital circuit - Study published in Nature Communications

Scientists at the Institute of Science and Technology Austria (IST Austria) have managed to control the behavior of individual bacteria by connecting them to a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

AKL’18: The opportunities and challenges of digitalization in the laser industry

07.12.2017 | Event News

 
Latest News

Multi-year submarine-canyon study challenges textbook theories about turbidity currents

12.12.2017 | Earth Sciences

Electromagnetic water cloak eliminates drag and wake

12.12.2017 | Power and Electrical Engineering

Liver Cancer: Lipid Synthesis Promotes Tumor Formation

12.12.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>