Reading the Sun’s Fireworks: How Flare Ribbons Reveal Hidden Solar Explosions
Solar flares are among the most powerful explosions in the solar system, releasing vast amounts of energy in minutes in the Sun. This huge energy release is associated with a rearrangement of the solar magnetic field high in the solar atmosphere. At the center of this process is magnetic reconnection, the process which allows the generation of new pathways through which hot solar material can travel. But despite decades of study, scientists still struggle to explain exactly how that energy is unleashed so quickly. A new study by a team led by U.S. National Science Foundation (NSF) Daniel K. Inouye Solar Telescope Ambassador Marcel Corchado Albelo takes an unexpected approach: instead of looking directly at where the energy is generated—high in the Sun’s faint upper atmosphere—it looks at subtle shapes closer to the solar surface.
“The smallest details of the shapes are what enable us to make the best predictions,” Corchado Albelo explains.
Because the upper atmosphere is so dim, the team analyzed bright regions lower down, where flare energy ultimately lands. By carefully measuring the intricate, irregular shapes of these energy deposition sites—the flare ribbons—they uncovered clues about the hidden processes above. The key finding: the region where energy is converted does not act as one smooth, unified source. Instead, it fragments into many pieces of different sizes, releasing energy in bursts rather than a steady flow.
This is a first. “For the first time we have experimentally shown a physical relationship between the irregular shapes we observe, and the structure of the energy conversion region,” Corchado Albelo notes.
The breakthrough also highlights the importance of next-generation solar telescopes. While the study used data from NASA’s IRIS satellite, the method was designed for even sharper observations from advanced instruments capable of resolving features as small as tens of kilometers—revealing details up to 20 times finer than before. In fact, their method was built to eventually integrate directly with the Inouye Solar Telescope, built and managed by the NSF National Solar Observatory (NSO). With the ability to resolve features as small as 24 kilometers with its Visible Broadband Imager (VBI) instrument, the Inouye can detect structures about 20 times smaller than IRIS can see. This extraordinary resolution makes it uniquely suited to probe the tiniest details in flare “footprints,” turning previously invisible structure into measurable data—and making it the most precise instrument yet for studying how flare energy is distributed and converted in space.
“For years, simulations have suggested that flare ribbon boundaries should behave a particular way,” says NSO scientist and co-author of the study Maria Kazachenko. What has been missing is a way to measure this on the Sun. “In this work, for the first time, we provided a quantitative observational test of those simulations. By applying a novel tool, adapted from a completely different field, Corchado Albelo was able to show that ribbon complexity increased with reconnection rate. It’s a beautiful example of theory, observation, and collaboration coming together, driven by the persistence and creativity of a graduate student,” adds Kazachenko who advises Corchado Albelo’s graduate work.
What makes this discovery especially compelling is its almost detective-like approach: by studying the messy outlines of glowing regions on the Sun, scientists can reconstruct invisible processes happening far above them. Or, as Corchado Albelo puts it, “we can diagnose what’s happening in the energy conversion region by studying the irregularities of these shapes.”
Beyond advancing solar physics, this work helps explain why solar flares erupt in sudden, intense bursts—knowledge that could ultimately improve our understanding of space weather and its effects on Earth.