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It is much hotter than the surface corona Astra?

The reason corona - a top layer of the atmosphere of the Sun - can reach temperatures over 200 times higher than those of surface Astra was explained by researchers at the U.S. National Center for Atmospheric Research Boulder United States.

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According to AFP, to heat the corona to several thousand degrees Celsius and to accelerate to several hundred kilometers per second speed solar wind travels the universe in all directions, including toward the Earth, it takes more energy, says Scott McIntosh , whose study was published in the journal Nature.

Temperature of the Sun is about 6,000 degrees Celsius, but temperatures soar to 2-3 million degrees Celsius in the corona, which is far removed from its object center, where nuclear reactions occur, the source of this heat. How can this additional energy to reach the crown?

Hannes Alfvén, Swedish physicist, Nobel laureate in 1970, predicted the existence of waves that convey this energy through the magnetic field lines going through the plasma (charged particles) of the crown. Until then, those which were not detected in sufficient quantities to provide energy.

With high definition images ultaviolet spectrum made with a fast cadence (every 8 seconds) satellite Solar Dynamics Observatory (SDO), the team led by Scott MacIntosh was able to detect these waves Alfvén.

They propagate with a very high speed (200-250 km / second) by plasma in motion, said in a statement from Professor Marcel Goossens Université Catholique de Louvain, who participated in this study.

The energy flow of 100-200 watts / cubic meter, these waves "are sufficient to provide the energy needed to propel the rapid wind and solar heat to offset losses in calm regions of the solar crown," concluded the authors.

But "they are not sufficient to provide 2,000 watts / cubic meter necessary to power active areas of the crown," added the authors, who believes that we need tools with improved spatial resolution and time "to study entire energy spectrum emitted in active regions. "