Magnetic waves theorized to transfer heat from the surface of the sun to its atmosphere have been directly observed for the first time, researchers report in the March 20 Science.

Astrophysicists have long puzzled over why the sun's atmosphere is millions of degrees hotter than the surface of the sun itself. "It's counterintuitive — when you hold your hands in front of a fire, it's hottest closest to the flames," says David Jess, an astrophysicist at Queen's University Belfast, in Northern Ireland, and a study coauthor.

The magnetic waves, called Alfvén waves, are considered the most plausible explanation for the transfer of so much energy from the sun's surface to its atmosphere. First theorized by Nobel laureate Hannes Alfvén in 1942, the waves could carry energy several hundred thousand kilometers from the sun's surface to the corona.

The new observation "is quite interesting," says astrophysicist Craig DeForest of the Southwest Research Institute in Boulder, Colo. "It means that we can get to the root of what's heating the corona."

Alfvén waves move along the sun's magnetic fields like "waves traveling along a string," Jess explains. The waves are created by magnetic reconnections, disturbances in the sun's magnetic field when magnetic lines twist, break apart and then snap back together again.
(Science NEws)