spacetoday.net: Solar wind origin linked to magnetic waves

Posted: Fri, Dec 7, 2007, 7:22 AM ET (1222 GMT)
Hinode image of solar north pole (SAO/NASA/JAXA/NAOJ)

Data from NASA instruments on a Japanese spacecraft have allowed scientists to identify the energy source for the solar wind. In papers published in Friday's issue of the journal Science, scientists reported on observations of the Sun made by instruments on Hinode, a Japanese solar science satellite launched last year. Data from the spacecraft allowed scientists to observe for the first time magnetic Alfven waves in the solar corona. Such waves, created when convective forces or sound waves move magnetic fields around or when electrical currents reshape magnetic fields, have been a leading theoretical mechanism for transferring energy from the Sun into the solar wind, accelerating it to speeds well over 1 million km/h. Those waves may also heat the solar corona to temperatures of millions of degrees.