Physicists observe waves that heat Sun's corona

William Atkins
Monday, 20 April 2009 21:21

Science - Space

An Alfvén wave is a type of magnetohydrodynamic wave, which is named after its discoverer, Swedish plasma physicist Hannes Alfvén, who won the Nobel Prize in Physics (in 1970) for his work on the theory of magnetohydrodynamics. He suggested in 1942 the existence of electromagnetic-hydromagnetic waves in a paper published in the journal Nature.

The waves are able to carry convective energy distances of up to hundreds of thousands of kilometers when carried in a plasma. In these circumstances the ions and magnetic field of the waves travel as a low-frequency oscillation.

The scientists conclude, “The energy flux associated with this wave mode is sufficient to heat the solar corona.”

Alfvén wave s were found, in 2007, to carry heat within the Sun, But, at the time, it was thought that they are not energetic enough to actually heat up the corona. Such discoveries were documented in a series of articles in the journal Science in December 2007 by scientists from Europe, Japan, and the United States.

One Science article is entitled “Alfvén Waves in the Solar Corona.”

At that time, the authors stated, “An estimate of the energy carried by the waves that we spatially resolved indicates that they are too weak to heat the solar corona; however, unresolved Alfvén waves may carry sufficient energy.”

Dr. Jess talks about future research when he states, “The next logical step is to measure how much energy the waves produce at different places in the sun’s atmosphere to figure out if Alfvén waves are the dominant mechanism for heating the whole solar atmosphere.” [Science News]