ESA/NASA The Solar Orbiter spacecraft has discovered many small jets of matter erupting from the Sun’s atmosphere. Each jet lasts 20-100 seconds and fires. plasma At approximately 100 km/s (60 mph) or 360,000 km/h (220,000 mph). These jets could be the source of the long-sought solar wind.
understanding the solar wind
The solar wind is made up of charged particles known as plasma that are continuously emitted from the sun. It propagates outward through interplanetary space, colliding with anything in its path. Auroras occur when the solar wind collides with the Earth’s magnetic field.
The solar wind is a fundamental feature of the Sun, but understanding where and how it originates near the Sun has proven difficult and has been an important focus of research for decades. Ta. Now, thanks to its superior equipment, the Solar Orbiter has brought us one step closer.
High-resolution imaging of the solar surface
Data are taken from the Solar Orbiter’s Extreme Ultraviolet Imager (EUI) instrument. An image of the Sun’s south pole, taken by the EUI on March 30, 2022, reveals a cluster of faint, short-lived features associated with tiny plasma jets ejected from the Sun’s atmosphere.
“Thanks to the unprecedented high-resolution, high-rhythm images produced by the EUI, we were only able to detect these tiny jets,” said Max of Germany, lead author of the paper describing the study. Lakshmi Pradeep Chitta of the Planck Institute for the Solar System said. . In particular, these images were taken in the extreme ultraviolet channel of his EUI’s high-resolution imager, which observes the solar plasma at a wavelength of 17.4 nanometers and at millions of degrees.
Of particular importance is the fact that analyzes show that these features are caused by plasma emissions from the solar atmosphere.
This movie was created based on observations taken by the ESA/NASA Solar Orbiter spacecraft between 04:30 and 04:55 on March 30, 2022. UTC, was released earlier last year. It shows that there is a “corona hole” near the south pole of the sun. Subsequent analysis revealed numerous small jets being emitted during observations. They appear as small flashes of bright light across the image. Each emits charged particles known as plasma into space. The circle represents the size of the earth on a scale. Credit: ESA & NASA/Solar Orbiter/EUI Team.Acknowledgments: Lakshmi Pradeep Chitta, Max Planck Institute for the Solar System
Magnetic structures and the solar wind
Researchers have known for decades that a significant portion of the solar wind is associated with magnetic structures called coronal holes, regions where the Sun’s magnetic field does not return to the Sun. Instead, the magnetic field extends deep into the solar system.
Plasma can flow along these “open” magnetic field lines and into the solar system, creating the solar wind. But the question is, how was the plasma launched?
The conventional assumption was that the corona, being so hot, would naturally expand and part of it would escape along the magnetic field lines. But these new results examine a coronal hole that was located at the south pole of the Sun, and the individual jets revealed challenge the assumption that the solar wind only occurs in a steady, continuous stream. is throwing
“One of the results here is that this flow is not actually uniform. ‘, says Andrei Zhukov of the Royal Observatory of Belgium. , a collaborator on this study who led the Solar Orbiter Observation Campaign.
Jet energy analysis
The energy associated with each individual jet is small. At the top of coronal phenomena are X-class solar flares, and at the bottom are so-called nanoflares. X-flares have a billion times more energy than nano-flares. The tiny jets discovered by Solar Orbiter are even lower in energy, appearing about 1,000 times less energetic than nanoflares, and most of that energy goes into plasma ejections.
Their ubiquity suggested by new observations suggests that they emit a significant fraction of the material found in the solar wind. It could also be smaller, have more frequent events, and offer even more.
“I think finding something on the disk that does contribute to the solar wind is an important step,” says David Bergmans, principal investigator of the EUI instrument at the Royal Observatory of Belgium.
Future Observations and Broader Impact
Currently, the Solar Orbiter still orbits the Sun near the equator. In other words, in these observations, the EUI sees Antarctica at a grazing angle.
“When you look at these little jets head-on, it’s hard to measure some of their properties, but in a few years we’ll be able to see the jets from a different perspective than other telescopes and observatories, so together It will help a lot,” he says. Daniel Muller, ESA Solar Probe Project Scientist.
That is, as the mission continues, the spacecraft Gradually tilt the orbit towards the poles. At the same time, solar activity progresses throughout the solar cycle and coronal holes begin to appear at different latitudes, offering a unique new perspective.
As this research extends beyond our solar system, everyone involved will be eager to see what fresh insights can be gleaned.
The Sun is the only star whose atmosphere we can observe in such detail, but the same process probably occurs in other stars as well. This turns these observations into discoveries of fundamental astrophysical processes.
Reference: “Picoflare jets power the solar wind emerging from the sun’s coronal holes,” LP Chitta, AN Zhukov, D. Berghmans, H. Peter, S. Parenti, S. Mandal, R. Aznar Cuadrado, U. Schühle, L. Terrierka, F. Aucher, K. Barchinski, É. Buchrin, L. Halla, E. Kreikamp, DM Long, L. Rodriguez, C. Schwanitz, PJ Smith, C. Verbeek, D.B. Seton, 24 Aug 2023, science.
DOI: 10.1126/science.ade5801
Solar Orbiter is an international space mission operated by ESA and NASA.