New Look Inside Sun’s Atmosphere Yields Clues About Mysterious Solar Wind

Heavy data cleaning allowed scientists to study the sun’s corona, or outer atmosphere, in stunning detail. Credit: Craig DeForest, SwRI
Our sun is surrounded by a deep, million-degree atmosphere that affects everything in the solar system — but how, precisely, it does so is a mystery.

By Meghan Bartels |

The atmosphere, called the corona, produces the solar wind — a flood of charged particles that stream out of the sun and across the solar system. As the solar wind travels to Earth, it brings threats of radiation and magnetic interference.

Now, in a new study, researchers have finally managed to watch it being born in the sun’s outer corona. The images provide enough detail for researchers to be able to start piecing together why it flows in such complex ways. They have concluded that one likely explanation is that the turbulence is a legacy of where it comes from. [During Eclipses, Astronomers Try to Reveal the Secrets of the Solar Wind]

„Previous images showed the outer corona as a smooth structure, but in deep space, the solar wind is turbulent and gusty,“ co-author Craig DeForest, a solar physicist at the Southwest Research Institute in Texas, said in a university statement. „Using new techniques to improve image fidelity, we realized that the corona is not smooth, but structured and dynamic. Every structure that we thought we understood turns out to be made of smaller ones, and to be more dynamic than we thought.“

The research relied on data from STEREO, a NASA mission that has been orbiting the sun since 2006. It carries an instrument called a coronagraph, which uses a black disk to block out the bright surface of the sun. That lets scientists see what’s happening in the corona, which is much fainter than the surface and would otherwise be washed out by its light.

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