Small-scale structure of the solar wind emerging from the sun’s coronal hole
ESA& NASA/Solar Probe/EUI/Lakshmi Pradeep Chitta
Powerful solar winds can originate from small plasma jets. The solar wind is a mass of charged particles, and exactly how those particles flow out of the sun has been debated for decades, but new high-resolution images may finally tell us.
The discovery was made possible by the spacecraft Solar Orbiter, which launched in 2020. Since then, the spacecraft has taken some of the highest resolution images of the Sun ever produced. Pradeep Chitta Researchers at the Max Planck Institute for the Solar System in Germany examined these images to understand how plasma escapes the sun.
They focused on the sun’s dark spots called coronal holes. Coronal holes are regions where the Sun’s magnetic field opens into space, allowing particles to escape. It was known that tiny plumes of plasma emanated from these holes, but the researchers discovered that the most powerful solar flares, called picoflare jets, emit a trillionth of the radiation dose he does. I found an even smaller jet called
“There are little eruptions of material everywhere, not just in the plume,” Chitta said. “What’s amazing is that even in these dark, seemingly inactive parts of the coronal hole, you can see these jets, and they appear to be jets.” that is the most important. ”
The jets were about 200 to 500 kilometers in diameter, each ejecting material from the Sun at velocities exceeding 100 kilometers per second, with the strongest jets located in dark places away from larger plumes. The magnetic properties of coronal holes meant that the plasma within these jets leaked into interplanetary space.
Previously, it was thought that whatever phenomenon fed the solar wind had to be a stable and constant phenomenon. But there are enough of these little jets on the Sun that together they could occupy all of the solar wind’s plasma, even though each one is long and he’s only active for a minute or so. . “It’s like how rivers flow on Earth: small streams and creeks flow from the tops of mountains, and eventually they join to form this big river,” Chitta says.
The properties of these small but powerful jets could also explain some of the strange structures that astronomers have seen in the solar wind. Because they can pack so close to each other, if two jets in close proximity have different velocities, they can create shear forces and instabilities, a strange Z-shape known as the magnetic switchback of the solar wind. It can cause type structure.
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