New Study Shows Scientists Detailed Images of Energetic Particle Jets Expelled from the Sun

Southwest Research Institute (SwRI) scientists have observed the first close-ups of a source of energetic particles ejected from the sun, viewing them from just half an astronomical unit (AU), or about 46.5 million miles. High-resolution images of the solar event were provided by ESA’s Solar Orbiter, a sun-observing satellite launched in 2020.

“In 2022, the solar probe detected six repeated active ion injections,” said Dr. Radoslav Busek of SwRI, lead author of a new study that published this month. Astronomy and Astrophysics Letters. “The solar orbit frequently detects this type of activity, but this period showed very unusual elemental combinations.”

In a single ion injection, the intensity of the rare isotope Helium-3 exceeded that of hydrogen, the most abundant element in the sun, and iron levels were comparable to that of helium-4, the second most abundant element on the sun. On another injection two days later, the amount of helium-3 dropped dramatically to an almost negligible amount.

“Our analysis shows that the initial and spectral differences in the repeated injections are related to the shape of the plane, the size of the flux source and the underlying photofield distribution that evolved over time,” Busiek said. “We believe that understanding the variability in recurring events from a single source sheds light on the acceleration mechanism in solar flares.”

The observations made by Solar Orbiter are unique because the diffusion effects that can affect abundance may be negligible near the Sun. The distance of just 0.5 AU gave the science team a remarkably detailed view of the solar events.

“When we’re closer, we have much better spatial resolution,” Busiek said. “We are able to gain more insight into the source of these energetic particles because we can see the internal structure associated with the accelerators as the injection develops. Observations from twice that distance, 1 astronomical unit, are not very clear by comparison.”

Bucik and colleagues hope to learn more from the Solar Orbiter’s closest approach to the Sun at 0.3 AU.

“These observations can help predict future solar-active particle events,” Busiek said. “These particles can damage satellites and equipment and potentially harm astronauts. We want to understand how they accelerate away from the sun and what are the conditions for accelerating them.”