International team of scientists reveals mechanism of solar wind ejection from coronal holes

Scientists from Skolkovo Institute of Science and Technology in cooperation with foreign colleagues have discovered how coronal holes – giant magnetic windows in the solar corona – eject streams of solar wind at supersonic speeds, shaping its movement throughout the heliosphere. This is reported by the press service of Skoltech, a partner of TV BRICS.

The wind blowing out from the surface of the Sun is a stream of charged particles that spreads throughout the solar system. However, its speed is not always the same: the fastest streams of particles are ejected through coronal holes – dark and cold parts of the solar atmosphere. This flow can cause both beautiful auroras and powerful geomagnetic storms that can disrupt satellites and affect power grids on Earth.

Based on the new data, scientists can now predict with greater accuracy when the solar wind will reach our planet. A solar observatory located on it will continuously monitor the Sun, providing data for operational warnings of solar storms. This will help protect Earth's critical infrastructure.

According to Tatiana Podladchikova, who heads the Engineering Centre at Skoltech, the study showed that coronal holes affect the solar wind depending on their size and location on the Sun.

“Imagine watering your garden with a hose. If you stand directly in front of the stream, you get hit hard. But if you’re off to the side, you only catch splashes. This ‘garden hose effect’ explains why satellites directly aligned with a solar wind stream measure higher speeds than those at an angle. Our study shows this effect is most pronounced for smaller coronal holes at higher solar latitudes, and depends strongly on the latitudinal separation between spacecraft. In contrast, larger coronal holes deliver solar wind more uniformly across the heliosphere,” she stated.

It is noted that the results will help to increase the advance predictions from a few hours to several days. This will significantly improve the safety of satellites, ground-based power grids, as well as aircraft that can be affected by solar storms.

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