Sun's Mysterious Waves Found; May Be Solar Wind Source

Richard A. Lovett
for National Geographic News
December 6, 2007

Powerful magnetic waves in the sun's atmosphere may be the energy source that drives the solar wind, a suite of new studies from a Japanese-led mission reports.

These so-called Alfvén waves were first predicted by Swedish physicist Hannes Alfvén, who won the 1970 Nobel Prize in Physics for his theory. (Read about the winners of this year's physics Nobel.)

The new studies of these waves were made possible by high-resolution instruments on the Hinode satellite, which was launched in September 2006.

Hinode, which means "sunrise" in English, is a joint mission of the Japanese Aerospace Exploration Agency (JAXA), NASA, the Particle Physics and Astronomy Research Council (PPARC), and the European Space Agency (ESA).

The orbiter's instruments allowed researchers to take rapid-fire pictures of various solar structures (see a March 21, 2007, Hinode image of the sun's turbulent magnetic field.)

Certain images were then combined into movielike photo sequences that showed how several solar structures interact with the long-suspected magnetic waves.

"These observations are unprecedented," said Jonathan Cirtain, a solar astrophysicist at NASA's Marshall Space Flight Center in Huntsville, Alabama. "It's just like [the features] are waving at you."

Three different teams, including one led by Cirtain, announce the find in tomorrow's issue of the journal Science.

Like Plucking Guitar Strings

The solar wind sweeps charged particles through space at speeds of about two million miles (three million kilometers) an hour—meaning that charged particles from the sun reach Earth's orbit within a couple of days.

"We live in the atmosphere of the sun," said Bart de Pontieu, a solar physicist at Lockheed Martin Corporation's Solar and Astrophysics Laboratory in Palo Alto, California.

De Pontieu is lead author of another of the new Alfvén wave studies.

Continued on Next Page >>




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