The solar wind represents a stream of charged particles (protons and electrons) that escape the Sun’s gravity and are being ejected from the upper atmosphere of the Sun. This phenomenon is linked directly to the geomagnetic storms or the Aurora Borealis, and it has been intensely studied by scientists. The magnetic field surrounding the Earth protects it from the direct electromagnetic energy transmissions and consequently, the solar wind can only be observed through the Aurora Borealis or the geomagnetic storms (caused by a solar wind shockwave striking the Earth’s magnetic field).

The Japanese Hinode space mission with ESA participation has been searching for answers on the origins of solar wind and on the Sun’s magnetic field. According to the data published in the Dec. 7 issue of Science magazine, the responsible for driving the solar wind into space are the Alfven waves, which transfer energy from the surface of the Sun through its atmosphere and into the solar wind.

Using a high resolution X-ray telescope, Hinode discovered large numbers of X-ray streams coming from what initially appeared to be fountains of plasma. The Alfven waves are released following a collision between two magnetic fields with opposite charge, and these collisions appear to be related to the gas particles that form the solar winds.

"Until now, Alfvén waves have been impossible to observe because of limited resolution of available instruments," said Alexei Pevtsov, Hinode program scientist at NASA according to the ESA.. "With the help of Hinode, we are now able to see direct evidence of Alfvén waves, which will help us unravel the mystery of how the solar wind is powered."

According to NASA physicist Jonathan Cirtain, "these observations show a clear relationship between magnetic reconnection and Alfvén wave formation in the X-ray jets. The large number of jets, coupled with the high speeds of the outflowing plasma, lends further credence to the idea that X-ray jets are a driving force in the creation of the fast solar wind."

Through the opening in May 2007 of the Hinode Science Data Center in Norway, European scientists have now full access to images and data from Hinode’s solar mission, which started in Sept. 2006.