When you imagine lightning, it tends to be pretty simple: an irregular sliver of light that splits the sky and disappears in less time than it takes to blink. But over the centuries, a strange image has emerged in a more horrifying form. Thousands of records and eyewitness accounts have told of balls of lightning floating above the ground before disappearing in a burst like soap bubbles. This fleeting phenomenon is nearly impossible to study, and reports vary wildly in descriptions of its size, tone, and even behavior, making it one of the most peculiar mysteries in atmospheric science. But if you can’t capture sparks in a field, reasoned physicist Chuliang Zhou and his colleagues at the Chinese Academy of Sciences, perhaps we can learn more by reproducing something similar in a laboratory. “Here we report the first controlled generation of a long-lived macroscopic soliton driven by relativistic terahertz electromagnetic fields,” the researchers write in a paper published in Nature Photonics. laboratory-accessible platform for research into the optical physics of solitons, advanced energy storage mechanisms, and the ancient scientific puzzle of ball lightning.” frameborder=”0″ enable=”accelerometer; autoplay; writing to clipboard; encrypted media; gyroscope; picture-in-picture; web-share” referrerpolicy=”strict-origin-when-cross-origin” enablefullscreen> A soliton is essentially a single, self-contained wave that maintains its shape and structural integrity through a delicate balance of physical forces. They can form in plasma, water, light, and potentially even some biological membranes—basically any medium where competing physical effects can balance to sustain a stable wave. Some theories suggest that ball lightning is a kind of electromagnetic soliton that traps energy in a layer of plasma. To be able to make this type of soliton, the researchers turned to a very, very sharp piece of tungsten. Well, it was a little more complicated than that, but the tungsten needle, with a tip just 100 nanometers wide, was essential. A human hair, for context, measures between 80,000 and 100,000 nanometers wide. The researchers fired an ultrashort laser pulse at the needle, generating a powerful electromagnetic wave that traveled along its length. At the tip, its energy was concentrated into an extraordinarily intense electric field that stripped electrons from atoms in a cloud of argon gas, creating a superheated bubble of ionized argon: plasma. It flickered into existence as a small ball of light. A schematic of the experimental setup, field map and simulations (above) and images showing the formation and expansion of the small plasma ball (Zhou et al., Nat. Photon., 2026) The fragile, luminous sphere began as. a puncture about 80 micrometers wide, then expanded to a larger puncture of several hundred micrometers over the next 100 nanoseconds. It may not seem like a long time, but it is much longer than the electromagnetic pulse from which it was born. And instead of simply dissipating like an ordinary cloud of hot plasma, the sphere maintained its structure as it expanded. The researchers tracked this expansion and analyzed the wavelengths of light the sphere emitted as it cooled, comparing their observations with theoretical models. and computer simulations. The researchers found that this expansion matched theoretical predictions for an electromagnetic soliton. This suggests that electromagnetic energy remained trapped within the plasma, helping to sustain the glowing orb even as it expanded. In contrast, their simulations of thermal expansion in ordinary plasma produced a much faster and more diffuse process. But a small point of light in a carefully controlled laboratory experiment is far from the wild atmospheric conditions in which ball lightning is typically reported. The small plasma ball photographed through six different wavelength filters, revealing how its light changed as it expanded. expanded and cooled (Zhou et al., Nat. Photon., 2026). The researchers then used their theoretical models to see how the phenomenon might behave on larger scales, driven by lower-frequency electromagnetic radiation. Their calculations suggested that electromagnetic solitons driven by microwaves, rather than terahertz radiation, could theoretically grow up to meters wide and persist for seconds. That’s much closer to some eyewitness reports of how mysterious ball lightning behaves. It’s far away. There’s no definitive explanation for lightning bolts, but solving meteorological mysteries isn’t the only potential application for these tiny fireballs. The ability to trap electromagnetic energy in a stable, localized structure could also open new avenues for energy storage technologies and study how light interacts with matter under extreme conditions. science and atmospheric geophysics, our findings redefine terahertz-driven platforms as engines of discovery for both applied technologies and unresolved natural phenomena.” The research has been published in Nature Photonics. This article was fact-checked by Rebecca Dyer and edited by Rebecca Dyer. While we are proud of our process, we are only human. If you spot an error, please let us know.
