The first close-ups of a source of energetic particles ejected from the Sun were observed by researchers at Southwest Research Institute (SwRI). These close-ups were viewed from just half an astronomical unit (AU) away, or nearly 46.5 million miles.
Southwest Research Institute (SwRI) scientists observed the first close-up views of the source of jets of energetic particles expelled from the Sun. The high-resolution images of the solar event were provided by ESA and NASA’s Solar Orbiter, a Sun-observing satellite launched in 2020. Image Credit: SwRI
The high-resolution images of the solar event were offered by ESA’s Solar Orbiter, a Sun-observing satellite launched in 2020.
In 2022, the Solar Orbiter detected six recurrent energetic ion injections. Particles emanated along the jets, a signature of magnetic reconnection involving field lines open to interplanetary space. The Solar Orbiter frequently detects this type of activity, but this period showed very unusual elemental compositions.
Dr. Radoslav Bucik, Study Lead Author, Southwest Research Institute
Bucik is the author of a new study reported in the journal Astronomy & Astrophysics Letters on May 2023.
In a single ion injection, the intensity of the rare isotope Helium-3 surpassed the amount of hydrogen, the most plentiful element on the Sun, and the levels of iron were the same as that of the isotope Helium-4, known to be the second most abundant element on the Sun. In another injection that happened two days later, the amount of Helium-3 had reduced considerably to a nearly insignificant amount.
Our analysis shows that the elemental and spectral variations in recurrent injections are associated with the shape of the jet, the size of the jet source, and the distribution of the underlying photospheric field that evolved over time. We believe that understanding the variability in recurrent events from a single source sheds light on the acceleration mechanism in solar flares.
Dr. Radoslav Bucik, Study Lead Author, Southwest Research Institute
The observations made by Solar Orbiter are special as the propagation effects that could impact abundances can be least near the Sun. The distance of just 0.5 AU has provided the scientific team with an extraordinarily elaborate view of solar events.
When we are closer, we have a considerably better spatial resolution. We are able to gain more insight into the source of these energetic particles because we can see the internal structure associated with acceleration processes as the injection evolves. Observations from twice that distance, 1 AU, are not very clear in comparison.
Dr. Radoslav Bucik, Study Lead Author, Southwest Research Institute
Bucik and his collaborators hope to gain more insights into the Solar Orbiter’s closest approaches to the Sun at 0.3 AU.
Bucik stated, “These observations could help predict future solar energetic particle events. These particles can damage satellites and equipment and potentially harm astronauts. We want to understand how they accelerate away from the Sun and what the conditions are for their acceleration.”
Journal Reference:
Bučík, R., et al. (2023) Recurrent 3He-rich solar energetic particle injections observed by Solar Orbiter at ∼0.5 au. Astronomy & Astrophysics. https://doi.org/10.1051/0004-6361/202345875.