UNIVERSITY PARK, Pa. — Lightning formation and the conditions triggering it have long been shrouded in a cloud of mystery, but new research led by Penn State scientists is lifting the fog. Using mathematical calculations, the researchers discovered that lightning-like discharge doesn’t require a storm cloud — it could be made inside everyday material on a lab bench.
“We applied the same exact models that we use for lightning research but shrunk down the scale to slightly larger than a deck of cards,” said Victor Pasko, professor of electrical engineering at Penn State and lead author on a paper describing the discovery in the journal Physical Review Letters . “We calculated that when supplied with a high-powered electron source, lightning can be triggered in everyday insulating materials like glass, acrylic and quartz.”
The team used detailed numerical simulations to show that lightning‑like radiation bursts could form inside small solid blocks, under conditions achievable in the lab . The work, if proven experimentally, could have implications for more compact and potentially safer X-ray sources in doctor offices and security checkpoints, the researchers said. The primary benefit, however, would be to enable the study of a powerful natural phenomenon at a lab bench.
This process, called a photoelectric feedback discharge, opens new pathways for studying lightning physics under controlled conditions to investigate how lightining is triggered and propagates, Pasko explained. If confirmed experimentally, the finding would dramatically shrink the scale at which one of nature’s most extreme electrical phenomena can occur.
“We were amazed because we were able to model the same phenomena in a material one thousand times denser than air, and strike a thousand times faster than in thunder clouds – one-billionth of a second,” Pasko said.
Typically, thunderstorms can produce electric potentials of about 100 million volts across kilometer-scale regions of cloud, Pasko explained, but the research team found that dense, solid materials can mimic those same electric conditions over just a few centimeters.
Acrylic, quartz and bismuth germanate — a hard crystal commonly used for X-ray detection in labs and supporting experiments in space — are roughly one thousand times denser than air, Pasko explained. Their density, combined with charge buildup from an energetic beam would theoretically allow the materials to reach lightning‑like electrical potentials in a space smaller than a thumb. The researchers argued that these conditions, similar to those used in previous experiments , can trigger the same photoelectric feedback loop previously thought to only appear in thunderstorms.
Lightning typically forms from mismatched electrical charges clashing in Earth’s atmosphere or between the atmosphere and Earth’s surface. Electrons move through a storm’s electric field, colliding with nitrogen and oxygen atoms, resulting in intense blasts of gamma rays, some of the highest bursts of energy found in nature. When triggered by lightning on Earth, such bursts are called terrestrial gamma‑ray flashes, and they are powerful enough to send beams of radiation hundreds of miles into space.
The team previously discovered that several types of emissions, such as X-rays and radio waves, are produced by accelerated electrons colliding with air molecules in thunderclouds. The resulting energy, in the form of an electron avalanche, triggers lightning initiation.
This phenomenon, called a relativistic runaway electron avalanche, is at the center of the team’s theoretical work. Similar to snow avalanches, electrons can snowball into larger and larger numbers. Under strong electric fields, like those in thunderstorms, electrons can accelerate so rapidly that they “run away,” gaining high levels of energy and emitting X‑rays and gamma rays as they slow down in surrounding material, Pasko explained.
In thunderstorms, these runaways create a chain reaction: the electrons slam into air molecules, producing high‑energy photons that ricochet backward and knock loose even more energetic electrons. In the study, the researchers modeled conditions in everyday materials that can trigger that same runaway photoelectric feedback loop previously thought only to occur in storm clouds.
“If you're able to experiment with lightning-like conditions on a desktop under controlled conditions, it would be wonderful — much more cost-effective and could answer so many questions,” Pasko said.
A greater understanding of lightning formation would allow for advances in several adjacent branches of science, such as meteorology. Today, it’s expensive to study lightning in clouds, Pasko explained. Researchers have to perform massive scale experiments to observe thunderclouds, usually hundreds of cubic kilometers in volume, and launch balloons, aircraft or rockets to study them.
However, a recent study by another team of scientists showed discharges with features remarkably resembling lightning were able to propagate in a small volume of particular materials. Based on this research insight, Pasko said he wanted to see if a mathematical model could describe and replicate the same photoelectric feedback loop that triggers lightning in miniature desktop conditions with dense materials such as acrylic, quartz and bismuth germanate.
“It just needs to be a kind of insulating material — theoretically you can reproduce this large-scale phenomena that we see in lightning in a very small volume,” Pasko said. “For us to realize that these voltages and electric fields, generated inside of these materials that are theoretically the same as in thunder clouds, was a real breakthrough.”
Other authors on the paper are Sebastien Celestin, professor of physics at the University of Orléans, France, and Anne Bourdon, director of research at École Polytechnique, France, and The French National Center for Scientific Research.The U.S. National Science Foundation funded the Penn State aspects of this research.
At Penn State, researchers are solving real problems that impact the health, safety and quality of life of people across the commonwealth, the nation and around the world.
For decades, federal support for research has fueled innovation that makes our country safer, our industries more competitive and our economy stronger. Recent federal funding cuts threaten this progress.
Learn more about the implications of federal funding cuts to our future at Research or Regress .
Physical Review Letters
Computational simulation/modeling
Not applicable
Relativistic Feedback Discharges in Dielectric Solids
5-Mar-2026