New images of the solar corona from this August's eclipse reveal a coronal hole that could affect Earth's magnetic field through high-speed solar wind, as well as swirling structures nicknamed “smoke rings”. Professor Miloslav Druckmüller from Brno University of Technology created the images by mathematically processing the collected data using his own specialised software. He will present the images to the public for the first time during Researcher´s Night at the Faculty of Mechanical Engineering on Friday, 25 September 2026.

Europe experienced a total solar eclipse in mid-August. The remarkable images reveal details that are completely invisible to the naked eye. The Sun goes through a cycle lasting approximately eleven years, during which its activity and magnetic field configuration change. At solar minimum, the Sun has two clearly defined magnetic poles. At solar maximum, however, their orientation changes and the magnetic field becomes much more chaotic. This year's eclipse occurred shortly after the Sun had passed the peak of its cycle.

High-speed solar wind can escape through a coronal hole

“The image shows the Sun shortly after its activity maximum, when its magnetic field is beginning to reorganise. The north and south magnetic poles are becoming clearly defined and visible again,” Druckmüller explains.

One of the most striking features revealed in this year's image of the corona is a coronal hole. This is a region where magnetic field lines do not loop back towards the Sun but instead extend far into interplanetary space.

“Very fast solar wind, a stream of electrically charged particles, can escape through a coronal hole. If this stream reaches Earth, it can have a powerful effect on our planet's magnetic field,” Druckmüller explains. This can trigger geomagnetic activity, producing phenomena such as auroras at lower latitudes or, during more intense events, disrupting radio communications, satellites and navigation systems.

His team captured a similar structure in 2015, during a very similar phase of the previous solar cycle. “It's valuable to see this phenomenon recurring at the same stage of the cycle,” he says, adding that the data will be used for further research by astrophysicists at the University of Hawaiʻi.

“Smoke rings” resemble rings of cigarette smoke

The new images also reveal exceptionally clear examples of delicate vortex structures known as “smoke rings”. Druckmüller first captured them during an eclipse in 2008. At the time, scientists were unsure exactly what they were observing and spent several years searching for a physical explanation. Only later did they establish that these were vortex rings associated with instabilities in the plasma of the solar corona.

“This year, we managed to capture truly textbook examples of beautifully swirling vortices. There are an enormous number of them in this corona,” Druckmüller says.

Interestingly, space probes were only able to capture these structures ten years after they first appeared in images taken by the Brno mathematician. This further demonstrates the unique nature of the research carried out in Brno.

“Thanks to our expertise and American funding, we developed research that demonstrated how total solar eclipses make it possible to capture images that, even today, cannot be obtained by any means from space,” Druckmüller explains.

During this year's expedition to Spain, the researchers collected approximately four terabytes of data, equivalent to around one million photographs taken with an ordinary smartphone. Most of this consists of calibration data required for precise mathematical processing. In addition to images of the corona in white light, the team also recorded radiation emitted by several types of highly ionised iron. Druckmüller has yet to process these images.

Motorised camera focusing makes researchers' work easier for the first time

The images collected during the observations allow astrophysicists to study physical conditions in different parts of the corona and the processes that generate the solar wind. This was the sixteenth eclipse expedition undertaken by the BUT mathematicians, with 28 researchers taking part this year, including BUT students.

“Across five observation sites, the team had a total of 15 cameras, 40 cooled imaging cameras, 55 lenses and 20 control laptops. This year's technical innovation was motorised focusing for manual lenses, which significantly reduced the time needed to prepare the equipment, particularly when weather conditions were changing,” explains expedition member and mathematician Pavel Štarha.

Although high-quality equipment and the team's expertise are essential, the success of an expedition ultimately depends on the weather. The mathematicians were only able to collect data successfully in Spain, as rain and overcast skies prevented imaging at all their observation sites in Iceland. Even so, the researchers obtained several times more data than they had originally expected.

Next year's eclipse will be unusually long, lasting more than six minutes

The next solar eclipse will take place as early as next summer. On 2 August 2027, the path of totality will cross southern Spain, Gibraltar, North Africa and the Middle East.

“We're currently working intensively on the plans and logistics. We know for certain that we'll be going to southern Spain, and we're still selecting other locations,” says Miloslav Druckmüller, adding that the research team must also consider safety in this region. Given the short interval between the two eclipses, the team is not planning any major equipment upgrades.

INFOBOX: About total solar eclipses When does a total solar eclipse occur? A total solar eclipse occurs when the Moon completely covers the Sun's disc, briefly allowing us to observe the solar corona, which is normally hidden by the Sun's intense light. Bright stars and some planets also become visible in the sky. "The fact that we can observe a total solar eclipse is an incredible coincidence. No other celestial body in the Solar System can produce a total eclipse of the Sun – they appear either larger or smaller than the Sun. But from Earth, the Moon appears to be exactly the same size as the Sun, making this breathtaking phenomenon possible," Druckmüller explains. The next total solar eclipse will be visible on 2 August 2027 and will be unusually long, lasting up to 6.5 minutes. The path of totality will begin in Spain and continue across North Africa (Morocco and Egypt) to Saudi Arabia. Australia will experience this breathtaking phenomenon the following year. The Czech Republic will have to wait until 7 October 2135.