'Solar storms behave like supernovae'
Researchers have explained for the first time the details of how solar storms behave as they fall back onto the Sun's surface.
David Williams, one of the study's authors, said that they've known for a long time that the Sun has a magnetic field, like the Earth does but in places it's far too weak to be measured, unless they have something falling through it, asserting that the blobs of plasma that rained down from this beautiful explosion were the gift that they'd been waiting for.
The 7 June 2011 eruption was by some margin the biggest recorded since this constant monitoring began, meaning the huge cascade of matter that fell back into the Sun following the eruption was a unique opportunity to study, on an unusually large scale, the fluid dynamics of these phenomena.
The team noticed in NASA Solar Dynamics Observatory (SDO) high-resolution images that the falling plasma clearly underwent the Rayleigh-Taylor instability as it returned to the Sun's surface. This is as would be expected -- the solar plasma is denser than the solar atmosphere it is falling through. In space, a similar effect has been observed before, albeit on a much larger scale, in the Crab Nebula.
The Crab Nebula is the remnant of a supernova which exploded in the 11th century. In the millennium that has followed the explosion, denser matter has started to fall back into the center of the nebula, exhibiting the same finger-like structures as the team observed in the Sun.
The UCL team found that the same effect was going on in the 7 June 2011 coronal mass ejection: even in an area where the Sun's magnetic field was weak, it was modifying the Rayleigh-Taylor effect, changing the shape of the plume of plasma as it fell back into the Sun.
(Posted on 21-02-2014)