A team of scientists led by the heliophysics group at Southwest Research Institute (SwRI) has used observations of Comet Encke’s tail using NASA’s Solar and Terrestrial Relations Observatory, or STEREO, revealed that the solar wind flows through the vacuum of interplanetary space much as the wind blows on Earth: not smoothly, but with gusting turbulence and swirling vortices.
That turbulence can help explain two of the wind’s most curious features: its variable nature and unexpectedly high temperatures. A paper on the STEREO results was published in The Astrophysical Journal on Oct. 13, 2015.
“The solar wind at Earth is about 70 times hotter than one might expect from the temperature of the solar corona and from how much it expands as it crosses the void,” said Dr. Craig DeForest, a solar physicist at SwRI in Boulder, Colo., and lead author on the study. “The source of this extra heat has been a mystery of solar wind physics for several decades.”