The ESA/NASA-operated Solar Orbiter spacecraft has unveiled the presence of minuscule jets emanating from the Sun’s external atmosphere, thereby offering potential insights into the source of solar winds. These new revelations challenge conventional theories about the genesis of solar winds, suggesting that the outflows may be sporadic rather than constant. The discovery could hold broader ramifications for the study of other celestial bodies’ atmospheres. Credit for the findings goes to ESA & NASA’s Solar Orbiter/EUI Team and Lakshmi Pradeep Chitta of the Max Planck Institute for Solar System Research.
A Closer Look at Solar Winds
Comprised of charged particles, or plasma, solar winds are a continual emission from the Sun, propagating through interplanetary space and interacting with any matter they encounter. When these winds interact with Earth’s magnetic field, they result in phenomena such as aurorae.
Despite its fundamental nature, the origins of the solar wind near the Sun have long eluded scientific understanding and have been the subject of intensive research for many years. However, the advanced instruments aboard the Solar Orbiter have brought us a step closer to resolving this puzzle.
High-resolution images from the spacecraft’s Extreme Ultraviolet Imager (EUI) have revealed numerous faint, short-lived features associated with minor jets of plasma being expelled from the Sun’s atmosphere. These features were visible owing to the exceptional resolution and high-frequency imaging provided by the EUI, particularly in its extreme ultraviolet channel, which observes solar plasma at a wavelength of 17.4 nanometers.
The study underscores that these features result from the ejection of plasma from the Sun’s atmosphere.
The Role of Magnetic Structures in Solar Winds
For many years, researchers have posited that a significant portion of the solar wind is linked to magnetic structures known as coronal holes—areas where the Sun’s magnetic field extends outwards rather than looping back into the Sun. Plasma follows these open magnetic lines into the solar system, thereby generating solar winds.
Traditional models assumed that the high temperature of the corona would naturally lead to expansion, enabling a part of it to escape along these field lines. However, the newly discovered jets from the Sun’s south pole indicate that solar winds might instead arise from intermittent outflows, challenging longstanding theories.
Evaluating the Energy of Solar Jets
Although the energy carried by each individual jet is minimal, the frequency with which they occur suggests they may contribute a substantial amount of material to the solar wind. Further, there could be even more frequent, smaller events contributing additional material.
According to David Berghmans of the Royal Observatory of Belgium and the principal investigator for the EUI instrument, this marks a significant advancement in understanding the solar wind.
Future Observations and Implications Beyond Our Solar System
As the Solar Orbiter continues its mission, it will increasingly focus on the Sun’s polar regions, offering a unique vantage point for further observations. As the Sun moves through its solar cycle, coronal holes will appear at different latitudes, offering new perspectives.
The findings have implications beyond our solar system. The Sun is the only star whose atmosphere can be observed in such fine detail, and it is likely that similar processes occur on other stars, making this discovery significant for astrophysics as a whole.
Reference: The scientific paper titled “Picoflare jets power the solar wind emerging from a coronal hole on the Sun,” was published on August 24, 2023, in the journal Science. DOI: 10.1126/science.ade5801
The Solar Orbiter is an international space mission, a collaboration between ESA and NASA, and is operated by ESA.
