Scientists solve solar secret
The further we move away from a heat source, the cooler the air gets. Bizarrely, the same can't be said for the Sun, but University of Otago scientists may have just explained a key part of why.Study lead Dr Jonathan Squire, of the Department of Physics, says the surface of the Sun starts at 6000 degree C, but over a short distance of only a few hundred kilometers, it suddenly heats up to more than a million degrees, becoming its atmosphere, or corona.
"Astrophysicists have several different ideas about how the magnetic-field energy could be converted into heat to explain the heating, but most have difficulty explaining some aspect of observations," he says. The group used six-dimensional supercomputer simulations of the coronal gas to show how these two theories are actually part of the same process, linked together by a bizarre effect called the 'helicity barrier'."If we imagine plasma heating as occurring a bit like water flowing down a hill, with electrons heated right at the bottom, then the helicity barrier acts like a dam, stopping the flow and diverting its energy into ion cyclotron waves.
Understanding more about the Sun's atmosphere and the subsequent solar wind is important because of the profound impacts they have on Earth, Dr Squire explains.
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