The Solar Orbiter spacecraft, a joint mission of the European Space Agency (ESA) and NASA, has confirmed that tiny jets discovered in 2023 near the Sun's south pole are the source of both fast and slow solar wind. These jets, which appear as hair-like wisps in sped-up video footage, exist in all dark regions of the Sun's atmosphere and last for about a minute, accelerating charged particles to speeds exceeding 100 kilometers per second.
The solar wind, a continuous stream of electrically charged particles emanating from the Sun, pervades the Solar System and impacts all the planets in orbit around it. While the fast solar wind has been known to originate from coronal holes, the source of the slow solar wind has remained elusive. This discovery provides the first definitive evidence that at least some of the slow solar wind originates from these tiny jets within coronal holes.
The researchers used the Solar Orbiter's imaging instruments to spot the jets within coronal holes at the Sun's equator. Combining these high-resolution images with in-situ measurements of solar wind particles and the magnetic field around the Sun, they were able to directly link the solar wind measured by the spacecraft to these jets.
The finding, published in Astronomy & Astrophysics, highlights the unique capabilities of the Solar Orbiter mission in unraveling the mysteries of our Sun. The researchers plan to gather more data during future close approaches to the Sun, aiming to gain a deeper understanding of how these tiny jets launch the solar wind.