With Hinode's higher sensitivity, Cirtain's team observed an average of 240 jets per day. They conclude that magnetic reconnection, a process where two oppositely charged magnetic fields collide and release energy, is frequently occurring in the low solar corona. This interaction forms both Alfvn waves and the burst of energized plasma in X-ray jets.
"These observations show a clear relationship between magnetic reconnection and Alfvn wave formation in the X-ray jets." said Cirtain. "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."
Another research team led by Bart De Pontieu, a solar physicist at Lockheed Martin's Solar and Astrophysics Laboratory, California, USA, focused on the Sun's chromosphere, the region sandwiched between the solar surface and its corona. Using extremely high-resolution images from Hinode's Solar Optical Telescope, De Pontieu's team found that the chromosphere is riddled with Alfvn waves. When the waves leak into the corona, they are strong enough to power the solar wind.
"We find that most of these Alfvn waves have periods of several minutes, much longer than many theoretical models have assumed in the past," says De Pontieu. Comparisons with advanced computer simulations from the University of Oslo, Norway, indicate that reconnection is not the only source of the Alfvn waves. "The simulations imply that many of the waves occur when the Sun's magnetic field is jostled around by convective motions and sound waves in the low atmosphere," continued De Pontieu.
|Contact: Bernhard Fleck|
European Space Agency