“New Findings by Solar Orbiter: Plasma Jets Unveiled as Potential Source of Solar Wind Generation”
The joint European Space Agency (ESA)/NASA Solar Orbiter spacecraft has made a groundbreaking discovery, uncovering a series of tiny jets of material being ejected from the Sun’s outer atmosphere. These plasma jets, which last for only 20 to 100 seconds and travel at speeds of 100 kilometers per second, could potentially be the source of solar wind. Solar wind is a continuous flow of charged particles, or plasma, that emanate from the Sun and interact with various objects in space, including Earth’s magnetic field, resulting in phenomena like the aurora borealis.
Scientists have long been puzzled by the origins of solar wind, and the recent findings from the Solar Orbiter mission may finally provide them with the answers they’ve been seeking for decades. The Sun possesses a high number of unique characteristics that have captivated researchers for generations, and solar wind is one of its most fundamental features. The causes of solar wind have been the focus of extensive studies in the field of heliophysics, with researchers striving to unravel its mysteries.
Launched in February 2020, Solar Orbiter has already provided scientists with invaluable data and images that have deepened our understanding of the Sun and its impact on our planet and the entire solar system. The spacecraft’s Extreme Ultraviolet Imager (EUI) instrument played an important role in the recent discovery of plasma jets. On March 30, 2022, the EUI captured high-resolution images of the Sun’s south pole in extreme ultraviolet wavelengths. These images revealed a group of small and faint features that were later confirmed to be plasma jets in the Sun’s outer atmosphere. The unprecedented high-resolution and high-cadence images produced by the EUI enabled scientists to detect these previously unseen phenomena.
Further analysis of the images demonstrated that the plasma jets are caused by the expulsion of plasma from within the solar atmosphere. These jets are found within magnetic structures called coronal holes, which are regions where the Sun’s magnetic field extends out into space instead of looping back down towards the Sun. It has long been known that coronal holes are associated with a significant portion of solar wind ejected from the Sun. Plasma can flow along the open magnetic field lines in these holes, resulting in solar wind.
Scientists have long hypothesized that the extreme heat of the Sun’s corona, or outer atmosphere, causes it to expand and contract, leading to the escape of plasma through coronal holes and contributing to solar wind. However, the discovery of the plasma jets challenges this assumption. The plasma jets found in the coronal hole at the Sun’s south pole suggest that solar wind may not be solely produced by a steady and continuous flow of plasma into space. Instead, these jets indicate that solar wind may originate from highly intermittent outflows.
Although each individual plasma jet is small and does not expel a significant amount of energy, their collective presence at the Sun’s south pole suggests that they contribute to the material found in solar wind. However, it’s likely that there are even smaller and more frequent coronal events that contribute to solar wind production. These findings represent a significant step forward in understanding the mechanisms behind solar wind generation.
While Solar Orbiter’s observations have shed light on coronal phenomena at the Sun’s south pole, its current orbit only allows for edge-on observations. However, over the coming months and years, Solar Orbiter will gradually change its orbit inclination, providing unprecedented views of the Sun’s polar regions. This change in perspective, combined with the Sun’s continued movement through a solar cycle, will enable scientists to observe new coronal holes and other solar phenomena.
The insights gained from Solar Orbiter’s mission are not only crucial for understanding our own Sun but also for studying other stars in the universe. With trillions of stars similar to our Sun, comprehending their internal workings and characteristics will enhance our understanding of the universe and the numerous solar systems that inhabit it. Solar Orbiter’s recent discoveries offer a glimpse into the intricate mechanisms that drive the Sun and shape our cosmic environment.
The results of the Solar Orbiter mission, led by Lakshmi Pradeep Chitta of the Max Planck Institute for Solar System Research, were published in the journal Science on August 24, 2023. As Solar Orbiter continues its mission and captures new images and data, scientists eagerly anticipate further revelations about the Sun and its impact on our solar system.
(Artist’s depiction of Solar Orbiter at perihelion. Credit: ESA/Medialab)
