In a groundbreaking discovery, ESA’s Solar Orbiter spacecraft has observed previously unknown “tiny” flares on the surface of the Sun, providing new insights into the origin of the solar wind. The solar wind, made up of charged particles emitted by the Sun, has long been associated with structures called coronal holes. These dark spots appear above the surface of the Sun when its magnetic field stretches in the solar system, allowing plasma to flow along open magnetic field lines and out into space. However, the exact mechanism of this process is still unclear.
Over the past few years, Solar Orbiter has been closely observing the Sun, acquiring images of the coronal hole in high-definition ultraviolet wavelengths. During these observations, the spacecraft recorded numerous jets of plasma ejected from the Sun’s corona. Although each jet was relatively small – several hundred kilometers long and reached speeds of about 100 kilometers per second, their number may account for a significant fraction of the solar wind.
Lead researcher Andrei Zhukov explains, “One of the results of the study is that to a large extent this flow is not actually homogeneous; the ubiquity of the jets suggests that the solar wind from coronal holes may arise as a highly discontinuous flow.” These results refute previous ideas about the homogeneity of the solar wind and emphasize the importance of studying these tiny flares to better understand space weather.
The detection of these “tiny” flares opens up new possibilities for studying the nature of the solar wind and its impact on space weather. A better understanding of these processes will allow scientists to improve space weather forecasts, which will be useful for future astronauts and spacecraft. Solar Orbiter will continue its mission, providing more detailed observations as its orbit changes, allowing a direct view of the Sun’s south pole, where the coronal hole was located.
Daniel Müller, ESA’s Solar Orbiter project scientist, emphasizes the importance of future observations: “Measuring some of the properties of these tiny jets is more difficult when they are seen from the edge, but in a few years we will see them from a different perspective than other telescopes and observatories, and this together should help a lot.”
The study, which sheds light on the origin of the solar wind, is published in the journal Science.